Posted on by

ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – Troubleshooting and Repair Manual

Engine Performance Troubleshooting Tree – ISC/QSC/ISL/QSL with CM850 Electronic Control System

Symptoms

    • Engine Acceleration or Response Poor
    • Cranking Fuel Pressure is Low
    • Engine Operating Fuel Pressure is Low
    • Engine Decelerates Slowly
    • Engine Difficult to Start or Will Not Start (Exhaust Smoke)
    • Engine Difficult to Start or Will Not Start (No Exhaust Smoke)
    • Engine Power Output Low
    • Engine Runs Rough at Idle
    • Engine Runs Rough or Misfires
    • Engine Speed Surges at Low or High Idle
    • Engine Speed Surges Under Load or in Operating Range
    • Smoke, Black – Excessive
    • Smoke, White – Excessive
    • Engine Shuts Off or Dies Unexpectedly or Dies During Deceleration
    • Engine Starts but Will Not Keep Running
    • Engine Will Not Reach Rated Speed (RPM)
    • Intake Manifold Pressure (Boost) is Below Normal

How To Use This Tree

This symptom tree can be used to troubleshoot all performance based symptoms listed above. Start by performing Step 1 troubleshooting. Step 2 will ask a series of questions and will provide a list of troubleshooting steps to perform depending on the symptom. Perform the list of troubleshooting steps in the sequence shown in the Specifications/Repair section of the tree.

Shop Talk

Driveability is a term that in general describes vehicle performance on the road. Driveability problems for an engine can be caused by several different factors. Some of the factors are engine-related and some are
not. Before troubleshooting it is important to determine the exact complaint and whether the engine has a real driveability problem or if it simply does
not meet driver expectations.

Low power is a term that is used in the field to describe many different performance problems. Low power is defined as the inability of the engine to produce the power necessary to move the vehicle at a speed that can be reasonably expected under the given conditions of load, grade, wind, and so on.

Poor acceleration or response is described as the inability of the vehicle to accelerate satisfactorily from a stop or from the bottom of a grade. It can also be the lag in acceleration during an attempt to pass or overtake another vehicle at conditions less than rated speed and load. Poor acceleration or response is difficult to troubleshoot since it can be caused by several factors.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Perform basic troubleshooting procedures.  
  STEP 1A. Check for active fault codes or high counts of inactive fault codes.
  STEP 1B. Perform basic troubleshooting checks.
STEP 2. Determination of engine symptom.  
  STEP 2A. Low power, poor acceleration, or poor response.
  STEP 2B. Engine misfire, engine speed surge, or engine speed unstable.
  STEP 2C. Excessive white or black smoke.
  STEP 2D. Low intake manifold pressure.
  STEP 2E. Engine will not start or difficult to start, engine shuts off unexpectedly.
STEP 3. No-start troubleshooting procedures.  
  STEP 3A. Verify the operation of cold weather starting aids.
  STEP 3B. Verify the low-pressure fuel lines are routed correctly.
  STEP 3C. Check the ECM keyswitch voltage.
  STEP 3D. Check the ECM battery supply voltage.
  STEP 3E. Check engine speed during cranking.
  STEP 3F. Verify rail fuel pressure sensor accuracy.
  STEP 3G. Check for fuel rail pressure while cranking the engine.
  STEP 3G-1. Check fuel gear pump pressure.
  STEP 3G-2. Check fuel lift pump pressure.
  STEP 3H. Check for other fault codes that explain a no-start condition.
STEP 4. Fuel system troubleshooting procedures.  
  STEP 4A. Check for fault codes.
  STEP 4B. Check for air in the high-pressure pump fuel supply.
  STEP 4C. Measure fuel gear pump pressure.
  STEP 4C-1. Measure the fuel inlet restriction.
  STEP 4D. Perform single cylinder cutout test.
  STEP 4E. Perform cylinder balance diagnostic test.
  STEP 4F. Measure fuel drain line restriction.
  STEP 4G. Monitor fuel pressure at idle.
STEP 5. Air handling troubleshooting procedures.  
  STEP 5A. Inspect the turbocharger blades for damage.
  STEP 5B. Check the turbocharger axial and radial clearances.
  STEP 5C. Determination of turbocharger type.
  STEP 5D. Check variable geometry actuator rod for correct travel.
  STEP 5D-1. Check for air leaks and inspect air lines.
  STEP 5D-2. Check for air pressure at the turbocharger control valve outlet.
  STEP 5D-3. Check for air pressure at turbocharger control valve outlet.
  STEP 5D-4. Check for vehicle air tank pressure at turbocharger control valve inlet.
  STEP 5D-5. Check for correct turbocharger actuator travel.
  STEP 5E. Check for broken shaft inside the turbocharger.
  STEP 5F. Inspect wastegate actuator – wastegated turbochargers only.
  STEP 5G. Inspect wastegate actuator rod for travel.
  STEP 5G-1. Inspect the wastegate actuator rod for travel.
STEP 6. Electronic feature troubleshooting procedures.  
  STEP 6A. Verify throttle pedal travel.
  STEP 6B. Check ambient air pressure sensor accuracy.
  STEP 6C. Check intake manifold pressure sensor accuracy.
  STEP 6D. Verify electronic feature settings are correct.
STEP 7. Base engine troubleshooting procedures.  
  STEP 7A. Verify overhead adjustments are correct.
  STEP 7B. Verify engine brake adjustment.
  STEP 7C. Inspect charge air-cooler.
  STEP 7D. Check air intake restriction.
  STEP 7E. Check exhaust restriction.
  STEP 7F. Check engine blowby.
  STEP 7F-1. Verify turbocharger contribution to engine blowby.

Guided Step 1 – Perform basic troubleshooting procedures.

Guided Step 1A – Check for active fault codes or high counts of inactive fault codes.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Check for active fault codes.

  • Use INSITE™ electronic service tool to read the fault codes.

Active fault codes or high counts of inactive fault codes?
YES NO

Follow the electronic fault code trees for the appropriate troubleshooting procedures.

 No Repair
Repair complete

Guided Step 1B – Perform basic troubleshooting checks.

Conditions

None.

Action

The following items must be checked or verified before continuing:

  • Verify the fuel level in the tanks
  • Verify there have
    not been any changes to CPL components on the engine
  • Verify fuel grade is correct for application
  • Verify the engine is operating within the recommended altitude
  • Verify engine oil is at the correct level
  • Verify engine parasitics have
    not changed
  • Verify engine duty cycle has
    not changed
  • Verify engine cranking speed is greater than 150 rpm
  • Verify battery voltage is adequate.

All steps have been verified to be correct?
YES NO
No Repair

Correct the condition and verify complaint is no longer present after repair.

Repair complete

Guided Step 2 – Determination of engine symptoms.

Guided Step 2A – Low power, poor acceleration, or poor response.

Conditions

None.

Action

Interview the driver and verify the complaint.

Is the engine symptom low power, poor acceleration, or poor response?
YES NO

Perform the troubleshooting steps in the recommended order listed below:

  • Step 4 – Fuel System Checks
  • Step 5 – Air Handling Checks
  • Step 6 – Electronics Checks
  • Step 7 – Base Engine Checks.
 No Repair
Perform the troubleshooting steps suggested in the repair procedure

Guided Step 2B – Engine misfire, engine speed surge, or engine speed unstable.

Conditions

None.

Action

Interview the driver and verify the complaint.

Is the engine symptom engine misfire, engine speed surge, or engine speed unstable?
YES NO

Perform the troubleshooting steps in the recommended order listed below:

  • Step 4 – Fuel System Checks
  • Step 5 – Air Handling Checks
  • Step 6 – Electronics Checks.
 No Repair
Perform the troubleshooting steps suggested in the repair procedure

Guided Step 2C – Excessive white or black smoke.

Conditions

None.

Action

Interview the driver and verify the complaint.

Is the engine symptom excessive white or black smoke?
YES NO

Perform the troubleshooting steps in the recommended order listed below:

  • Step 5 – Air Handling Checks
  • Step 4 – Fuel System Checks
  • Step 7 – Base Engine Checks.
 No Repair
Perform the troubleshooting steps suggested in the repair procedure.

Guided Step 2D – Low intake manifold pressure.

Conditions

None.

Action

Interview the driver and verify the complaint.

Is the engine symptom low boost pressure?
YES NO

Perform the troubleshooting steps in the recommended order listed below:

  • Step 5 – Air Handling Checks
  • Step 4 – Fuel System Checks
  • Step 7 – Base Engine Checks.
 No Repair
Perform the troubleshooting steps suggested in the repair procedure

Guided Step 2E – Engine will not start or difficult to start, engine shuts off unexpectedly.

Conditions

None.

Action

Interview the driver and verify the complaint.

Is the symptom engine will not start or difficult to start, engine shuts off unexpectedly?
YES NO

Perform the troubleshooting steps in the recommended order listed below:

  • Step 3 – No Start Checks
  • Step 4 – Fuel System Checks
  • Step 5 – Air Handling Checks
  • Step 6 – Electronics Checks.
 No Repair
Perform the troubleshooting steps suggested in the repair procedure
Return to correct symptom tree

Guided Step 3 – No-start troubleshooting procedures.

Guided Step 3A – Verify the operation of cold weather starting aids.

Conditions

  • Turn keyswitch ON.

Action

Make sure the intake air heater and other cold starting aids are operational.

Refer to Procedure 008-011 in Section 8.Refer to Procedure 010-029 in Section 10.

Are necessary cold weather starting aids operating properly?
YES NO
No Repair

Install or repair cold weather starting aids.

Refer to Procedure 010-029 in Section 10.

Repair complete

Guided Step 3B – Verify the low-pressure fuel lines are routed correctly.

Conditions

None.

Action

It is sometimes possible to get the low-pressure fuel lines connected to the ECM cooling plate installed improperly. The top connection to the ECM cooling plate is the inlet and the bottom connection is the outlet.

Verify these connections if the low-pressure fuel lines have been removed and installed on the engine.
SMALL | MEDIUM | LARGE

Are the low-pressure fuel lines connected properly to the ECM cooling plate?
YES NO
No Repair

Properly connect the low-pressure fuel lines to the ECM cooling plate. The fuel inlet is the top connection.

Repair complete

Guided Step 3C – Check the ECM keyswitch voltage.

Conditions

  • Disconnect the OEM harness from the ECM.
  • Turn keyswitch ON.

Action

Measure the signal voltage from the keyswitch input SIGNAL wire of the OEM harness to the engine block ground.

Measure the keyswitch voltage with the keyswitch in the ON position and also with the keyswitch in the Cranking position.

Refer to the wiring diagram for connector pin identification.
SMALL | MEDIUM | LARGE

Is the keyswitch voltage equal to battery voltage?
YES NO
No Repair

Repair or replace the OEM power harness, keyswitch, or check the battery connections.

Repair complete

Guided Step 3D – Check the ECM battery supply voltage.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the ECM power harness from the ECM.

Action

Measure the voltage from the ECM battery SUPPLY (-) pin to the ECM battery SUPPLY (+) pins in the ECM power harness connector.

Measure the ECM voltage with the keyswitch in the ON position and also with the keyswitch in the Cranking position.

Refer to the wiring diagram for connector pin identification.
SMALL | MEDIUM | LARGE

Is the ECM battery supply voltage equal to the battery voltage?
YES NO
No Repair

Repair or replace the ECM power harness. Check the battery connections and fuse terminals.

Repair complete

Guided Step 3E – Check engine speed during cranking.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to monitor Engine Speed while cranking the engine.

Is the engine cranking speed greater than 150 rpm?
YES NO
No Repair

Find and correct the cause for low cranking speed. Check the batteries, engine starting motor, and accessory loads.

Repair complete

Guided Step 3F – Verify rail fuel pressure sensor accuracy.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to monitor the Rail Fuel Pressure Sensor (Measured) with the keyswitch ON and the engine not running.

Is the rail fuel pressure sensor (measured) value less than 30 Bar [435 psi]?
YES NO
No Repair

Replace the rail fuel pressure sensor.

Use the following procedure in the Troubleshooting and Repair Manual, CM850 Electronic Control System, ISC and ISL Engines, Bulletin 4021416.
Refer to Procedure 019-115 in Section 19.

Repair complete

Guided Step 3G – Check for fuel rail pressure while cranking the engine.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Attempt to start the engine by engaging the engine starting motor for at least 30 continous seconds.

  • Use INSITE™ electronic service tool to monitor Fuel Rail Pressure (Measured) and Fuel Rail Pressure (Commanded).
  • Use INSITE™ electronic service tool to read the fault codes.

Attempting to start the engine for 30 continuous seconds allows the fault code logic time to run. If Fault Code 2215 becomes active, fuel rail pressure is
not being developed.

If the engine starts during this attempt, it is possible that fuel prime to the high pressure pump has been lost. Look for loose fuel lines or filters that allow for loss of fuel prime.

Did Fault Code 2215 become active during the failed the start attempt?
YES NO
No Repair No Repair

Guided Step 3G-1 – Check fuel gear pump pressure.

Conditions

Action

Measure the fuel gear pump output pressure while cranking the engine.

Cranking speed
must be greater than 150 rpm.

Refer to Procedure 005-025 in Section 5.

SMALL | MEDIUM | LARGE

Is the fuel gear pump pressure while cranking greater than the specification outlined in 005-025?
YES NO

Follow Fault Code 2215 troubleshooting tree.

 No Repair
Repair complete

Guided Step 3G-2 – Check fuel lift pump pressure.

Conditions

  • Install a pressure gauge at the inlet port of the high pressure pump gear pump.
  • Turn keyswitch ON.

Action

Measure the fuel lift pump output pressure.

Refer to Procedure 005-045 in Section 5.

At initial key ON, the lift pump will run for 30 seconds and then stop.
SMALL | MEDIUM | LARGE

Is the fuel lift pump pressure greater than the specifications outlined in Procedure 005-045 in the Troubleshooting and Repair Manual, ISC, QSC8.3, ISL and QSL9 Engines, Bulletin 4021418?
YES NO

Replace the gear pump.

Refer to Procedure 005-025 in Section 5.

Verify fuel prime by making sure the OEM fuel filter is full or fuel and air is purged from the low pressure fuel lines. Perform INSITE™ electronic service tool Lift Pump Override Test if necessary.

If the low pressure fuel system is primed, replace the fuel lift pump.

Refer to Procedure 005-045 in Section 5.

Repair complete
Repair complete

Guided Step 3H – Check for other fault codes that explain a no-start condition.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to read fault code information.

Look for fault codes that come active during a failed start attempt that can be the cause for a no-start condition.

Do any fault codes that can cause a no-start condition come active during cranking?
YES NO

Follow the electronic fault code trees for the appropriate troubleshooting procedures.

 No Repair
Repair complete

Guided Step 4 – Fuel system troubleshooting procedures.

Guided Step 4A – Check for fault codes.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to read the fault code information.

Determine if there are active fuel system fault codes related to the complaint.

Are fuel system fault codes active?
YES NO

Follow the electronic fault code trees for the appropriate troubleshooting procedures.

 No Repair
Repair complete

Guided Step 4B – Check for air in the high-pressure pump fuel supply.

Action

Check for air in the fuel.

Refer to Procedure 006-003 in Section 6.

Is air present in the fuel supply?
YES NO

Locate and correct the cause of air ingestion in the fuel supply system. Sources of air ingestion include loose fuel filters, loose fuel line fittings, loose or cracked fuel tank stand-pipes, or severe restrictions in the fuel supply lines and filters.

 No Repair
Repair complete

Guided Step 4C – Measure fuel gear pump pressure.

Action

Check the fuel gear pump pressure.

Refer to Procedure 005-025 in Section 5.

SMALL | MEDIUM | LARGE

Is the fuel gear pump pressure within specification?
YES NO
No Repair No Repair

Guided Step 4C-1 – Measure the fuel inlet restriction.

Conditions

Action

Check the fuel inlet restriction.

Refer to Procedure 006-020 in Section 6 .

SMALL | MEDIUM | LARGE

Is the fuel inlet restriction above specification?
YES NO

Find and correct the cause of high inlet restriction. Look for plugged OEM fuel filters or screens, or a restricted ECM cooler, restricted lift pump bypass check valve (in the ECM cooler), pinched OEM fuel lines or restricted stand-pipe in the OEM fuel tank.

Replace the fuel gear pump.

Refer to Procedure 005-025 in Section 5.

Repair complete
Repair complete

Guided Step 4D – Perform single cylinder cutout test.

Conditions

  • Turn keyswitch ON.
  • Engine running at low idle.
  • Connect INSITE™ electronic service tool.

Action

Operate the engine at load.

Use INSITE™ electronic service tool to perform the Cylinder Cutout Test to disable individual injectors.

Can the miss or excessive smoke be attributed to a single cylinder?
YES NO

Look for a cause of the complaint including valve lash and excessive crankcase pressure that can indicate power cylinder damage or camshaft lobe wear. If no other damage is found, replace the fuel injector in the cylinder identified by the single cylinder cutout test.
Refer to Procedure 006-026 in Section 6.

No Repair
Repair complete

Guided Step 4E – Perform cylinder balance diagnostic test.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to run the Cylinder Performance Test to determine if a single cylinder is contributing to the engine symptom.

Does the Cylinder Performance Test identify any cylinder that is contributing to a power imbalance?
YES NO

Look for a cause of the power imbalance including valve lash and excessive crankcase pressure that can indicate power cylinder damage or camshaft lobe wear. If no other damage is found, replace the fuel injector in the cylinder contributing to the power imbalance.
Refer to Procedure 006-026 in Section 6.

No Repair
Repair complete

Guided Step 4F – Measure fuel drain line restriction.

Action

Check the fuel drain line restriction.

Is the drain line restriction less than specification?
YES NO
No Repair

Look for causes of high drain line restriction, such as kinked or blocked fuel lines.

Repair complete

Guided Step 4G – Monitor fuel pressure at idle.

Conditions

  • Connect INSITE™ electronic service tool.
  • Start engine.

Action

Run engine at idle for at least one minute to purge air induced from previous steps.

Use INSITE™ electronic service tool to monitor commanded fuel rail pressure and measured fuel rail pressure for a minimum of 10 seconds.

To verify your results, repeat this step with the Fuel System Leakage Test active in the INSITE™ electronic service tool.
SMALL | MEDIUM | LARGE

Does measured fuel rail pressure deviate more than 200 bar [2900 psi] from commanded pressure and surge at idle, or does the engine start and stall?
YES NO

Replace the fuel pump actuator. Use the following procedure in the Troubleshooting and Repair Manual, CM850 Electronic Control System, ISC and ISL Engines, Bulletin 4021416.
Refer to Procedure 019-117 in Section 19.

No Repair
Repair complete.

Guided Step 5 – Air handling troubleshooting procedures.

Guided Step 5A – Inspect the turbocharger blades for damage.

Conditions

  • Turn keyswitch OFF.
  • Remove the intake and exhaust pipes from the turbocharger.

Action

Inspect the compressor and turbine blades for damage or wear.

Refer to Procedure 010-033 in Section 10.

Damage or wear found on turbocharger blades?
YES NO

Replace the turbocharger assembly.
Refer to Procedure 010-033 in Section 10.

No Repair
Repair complete

Guided Step 5B – Check the turbocharger axial and radial clearances.

Conditions

  • Turn keyswitch OFF.

Action

Check the turbocharger for correct axial and radial clearance.

Refer to Procedure 010-033 in Section 10.

Are the turbocharger axial and radial bearing clearances within specification?
YES NO
No Repair

Replace the turbocharger.
Refer to Procedure 010-033 in Section 10.

Repair complete

Guided Step 5C – Determination of turbocharger type.

Conditions

None

Action

Determine if the turbocharger is a wastegated or variable geometry turbo.

Is the turbocharger a variable geometry turbocharger?
YES NO
No Repair No Repair

Guided Step 5D – Check variable geometry actuator rod for correct travel.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.
  • Verify vehicle air tanks are fully charged (greater than 689 kPa [100 psi]).

Action

Use INSITE™ electronic service tool to start the Turbocharger Actuator Test

  • Adjust the delay timer in the Turbocharger Actuator Test so that the rod movement can be observed.
  • Select the Retract Actuator position with INSITE™ electronic service tool.
  • Mark or scribe the variable geometry actuator rod at the base of the actuator.
  • Select the Extend Actuator position with INSITE™ electronic service tool.
  • Measure the rod travel by measuring the distance from the base of the variable geometry actuator to the scribe mark.

The variable geometry actuator
must move quickly and crisply. If the actuator rod movement is slow, there could be a problem with the air supply or mechanical problems with the variable geometry turbocharger assembly.
SMALL | MEDIUM | LARGE

Does the turbocharger actuator rod extend between 8 and 9 mm [0.32 and 0.36 in]?
YES NO
No Repair No Repair

Guided Step 5D-1 – Check for air leaks and inspect air lines.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.
  • Verify vehicle air tanks are fully charged (greater than 689 kPa [100 psi]).

Action

Use INSITE™ electronic service tool to perform the Turbocharger Actuator Test.

Select the Extended Actuator position and listen for air leaks in the following components:

  • Turbocharger control valve
  • Turbocharger control valve inlet connection
  • Turbocharger control valve outlet connection
  • Turbocharger actuator inlet connection
  • Turbocharger actuator
  • All air lines including OEM supply line to turbocharger control valve and between the turbocharger control valve and the variable geometry turbocharger.

A small amount of air will be heard escaping from the turbocharger control valve. This is a normal condition. Do
not replace the turbocharger control valve for this condition.

Air leaks found in the system or damaged air lines?
YES NO

Repair air leaks or replace damaged or broken air lines.

 No Repair
Repair complete

Guided Step 5D-2 – Check for air pressure at the turbocharger control valve outlet.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.
  • Verify vehicle air tanks are fully charged (greater than 689 kPa [100 psi]).

Action

Remove the air line connection at the outlet of the turbocharger control valve.

Install a Compuchek™ fitting in the turbocharger control valve outlet.

Install an air pressure gauge that is capable of reading at least 1034 kPa [150 psi].

Use INSITE™ electronic service tool to perform the Turbocharger Actuator Test. Select the Extend position.

Is vehicle tank air pressure present at the turbocharger control valve outlet?
YES NO
No Repair No Repair

Guided Step 5D-3 – Check for air pressure at turbocharger control valve outlet.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.
  • Verify vehicle air tanks are fully charged (greater than 689 kPa [100 psi]).

Action

Remove the air line connection at the outlet of the turbocharger control valve.

Install an air pressure gauge that is capable of reading at least 1034 kPa [150 psi].

Use INSITE™ electronic service tool to perform the Turbocharger Actuator Test. Select the Retract position.

Can air be heard escaping from the turbocharger control valve outlet?
YES NO

The turbocharger control valve is stuck open. It
must not be allowing air to escape when in the Retract position. Replace the turbocharger control valve. Use the following procedure in the Troubleshooting and Repair Manual, CM850 Electronic Control System, ISC and ISL Engines, Bulletin 4021416.
Refer to Procedure 019-388 in Section 19.

No Repair
Repair complete

Guided Step 5D-4 – Check for vehicle air tank pressure at turbocharger control valve inlet.

Conditions

  • Turn keyswitch ON.
  • Verify vehicle air tanks are fully charged (greater than 689 kPa [100 psi]).

Action

Disconnect the air inlet connection to the turbocharger control valve.

Verify vehicle air tank pressure is available at the turbocharger control valve inlet.

Vehicle air tank pressure available at the turbocharger control valve inlet?
YES NO
No Repair

No air pressure available at the turbocharger control valve inlet. Troubleshoot OEM air plumbing and determine why air pressure is
not present.

Repair complete

Guided Step 5D-5 – Check for correct turbocharger actuator travel.

Conditions

Action

Use INSITE™ electronic service tool to perform the Turbocharger Actuator Test.

Select the Extend Actuator position.
SMALL | MEDIUM | LARGE

Does the variable geometry actuator rod travel at least 12 mm [0.472 in]?
YES NO

The variable geometry actuator has correct air pressure and correct travel. The variable geometry mechanism in the turbocharger is seized.

Replace the turbocharger assembly.
Refer to Procedure 010-033 in Section 10.

The variable geometry actuator has correct air pressure but the variable geometry actuator rod is
not extending.

Replace the turbocharger actuator.
Refer to Procedure 010-113 in Section 10.

Repair complete
Repair complete

Guided Step 5E – Check for broken shaft inside the turbocharger.

Conditions

Action

Check for a broken linkage inside the turbocharger by moving the variable geometry actuator on the turbocharger up and down.

The actuator lever
must move evenly and crisply as it is moved.
SMALL | MEDIUM | LARGE

Does the sliding nozzle move correctly?
YES NO
No Repair

The variable geometry has mechanical damage inside the turbocharger. The actuator moves properly, but the linkage attaching the actuator to the nozzle is broken.

Replace the turbocharger assembly.
Refer to Procedure 010-033 in Section 10.

Repair complete

Guided Step 5F – Inspect wastegate actuator – wastegated turbochargers only.

Conditions

  • Turn keyswitch OFF.
  • Remove the turbocharger if the wastegate actuator is inaccessible.

Action

Inspect the integral wastegate actuator hose for cracks or holes.

Holes or cracks found in the wastegate actuator hose?
YES NO

Replace the wastegate actuator hose.

 No Repair
Repair complete

Guided Step 5G – Inspect wastegate actuator rod for travel.

Conditions

  • Turn keyswitch OFF.
  • Remove the integral boost line from the wastegate actuator.

Action

Apply a regulated air supply of 138 kPa [20 psi] to the actuator and check for actuator movement.
SMALL | MEDIUM | LARGE

Does the wastegate actuator rod move?
YES NO
No Repair No Repair
Repair complete

Guided Step 5G-1 – Inspect the wastegate actuator rod for travel.

Conditions

  • Turn keyswitch OFF.
  • Remove the e-clip from the wastegate pin and disconnect the actuator rod.

Action

Apply a regulated air supply of 138 kPa [20 psi] to the actuator and check for actuator movement.
SMALL | MEDIUM | LARGE

Does the wastegate actuator rod move?
YES NO

Move the wastegate lever on the turbocharger back and forth, and check for smooth operation.

Replace the turbocharger assembly if the wastegate is seized.
Refer to Procedure 010-033 in Section 10.

Replace the wastegate actuator.
Refer to Procedure 010-050 in Section 10.

Repair complete
Repair complete

Guided Step 6 – Electronic feature troubleshooting procedures.

Guided Step 6A – Verify throttle pedal travel.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to monitor Throttle Position while fully depressing and releasing the throttle pedal.

Does the throttle position read 0 percent when the throttle is released and 100 percent when the throttle is depressed?
YES NO
No Repair

Determine and correct the cause of the throttle pedal restriction.

Repair complete

Guided Step 6B – Check ambient air pressure sensor accuracy.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Start INSITE™ electronic service tool Data Monitor/Logger and compare INSITE™ electronic service tool reading for Barometric Air Pressure to the local barometric pressure.

Refer to Procedure 018-028 in Section V.

The INSITE™ electronic service tool reading is within 50.8 mm-Hg [2 in-Hg] of local barometric pressure?
YES NO
No Repair

Replace the barometric pressure sensor. Use the following procedure in the Troubleshooting and Repair Manual, CM850 Electronic Control System, ISC and ISL Engines, Bulletin 4021416.
Refer to Procedure 019-004 in Section 19.

Repair Complete

Guided Step 6C – Check intake manifold pressure sensor accuracy.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool to monitor the value of Intake Manifold Pressure without the engine running.

Intake manifold pressure reading is less than 102 mm-Hg [4 in -Hg]?
YES NO
No Repair

Replace the intake manifold pressure sensor. Use the following procedure in the Troubleshooting and Repair Manual, CM850 Electronic Control System, ISC and ISL Engines, Bulletin 4021416.
Refer to Procedure 019-061 in Section 19.

Repair complete

Guided Step 6D – Verify electronic feature settings are correct.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Use INSITE™ electronic service tool; to verify the following adjustable parameters are correctly set:

  • Maximum Vehicle Speed
  • Powertrain Protection
  • Rear Axle Ratio
  • Tailshaft Teeth
  • Tire Revolutions per Mile
  • Gear-Down Protection
  • Cruise Control Droop Settings
  • Cruise Control Maximum Vehicle Speed.

Are the electronic features set correctly?
YES NO
No Repair

Use INSITE™ electronic service tool to correct programmable features.

Repair complete

Guided Step 7 – Base engine troubleshooting procedures.

Guided Step 7A – Verify overhead adjustments are correct.

Conditions

Action

Measure the overhead setting.

Refer to Procedure 003-004 in Section 3.

Are the overhead settings within the reset limits?
YES NO
No Repair

Adjust the overhead settings.
Refer to Procedure 003-004 in Section 3.

Repair complete

Guided Step 7B – Verify engine brake adjustment.

Conditions

Action

Verify that the engine brakes are operating correctly.

Measure the engine brake settings.
Refer to Procedure 020-004 in Section 20.

Are the engine brake settings within the reset limits?
YES NO
No Repair

Adjust the engine brake settings.
Refer to Procedure 020-004 in Section 20.

Repair complete

Guided Step 7C – Inspect charge-air cooler.

Action

Inspect the charge-air cooler for cracks, holes, or other damage.

Refer to Procedure 010-027 in Section 10.

SMALL | MEDIUM | LARGE

Is the charge-air cooler free of cracks or other damage?
YES NO
No Repair

Repair the charge-air cooler assembly.

Repair complete

Guided Step 7D – Check air intake restriction.

Action

Check the intake system restriction by installing a vacuum gauge into the air intake system.

Refer to Procedure 010-031 in Section 10.

SMALL | MEDIUM | LARGE

Is air intake restriction greater than 635 mm-H
2O [25 in-H
2O]?
YES NO

Correct the cause of high intake air restriction.

Check for plugged air filter or restricted air intake piping.

 No Repair
Repair complete

Guided Step 7E – Check exhaust restriction.

Action

Check the exhaust system back pressure by installing a pressure gauge into the exhaust system just past the turbocharger outlet.

Refer to Procedure 011-009 in Section 11.

SMALL | MEDIUM | LARGE

Is exhaust back pressure less than 40 in-H
2O [3 in-Hg]?
YES NO
No Repair

Inspect exhaust system for source of high restriction.

Repair complete

Guided Step 7F – Check engine blowby.

Action

Measure the engine blowby as outlined in Procedure 014-005.

Are the engine blowby measurements within specification?
YES NO
No Repair No Repair
Return to Step 2 or contact a Cummins® Authorized Repair Location for further diagnostic and troubleshooting instructions.
Go to step 7F-1.

Guided Step 7F-1 – Verify turbocharger contribution to engine blowby.

Conditions

  • Turn keyswitch OFF.
  • Connect the appropriate orifice to the end of the blowby draft tube.
  • Remove the turbocharger oil drain line from the block and drain into a bucket.
  • Start the engine.

Action

Load engine to rated rpm on a chassis dynamometer.

Measure the engine blowby as outlined in
Procedure 014-005 Section 14.

Has the total engine blowby dropped more than 30 percent of the total?
YES NO

Replace the turbocharger assembly.
Refer to Procedure 010-033 in Section 10.

The engine might need to be rebuilt. See the engine rebuild specifications.
Repair complete
Repair Complete
Last Modified:  12-Aug-2010
Avatar photo

Published by Jack

Hello, I'm Jack, a diesel engine fan and a blogger. I write about how to fix and improve diesel engines, from cars to trucks to generators. I also review the newest models and innovations in the diesel market. If you are interested in learning more about diesel engines, check out my blog and leave your feedback.