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Electronic Control System Gas Plus Engines – FAULT CODE 461 – B and C Gas Plus

Ignition Reference Signal Circuit – Shorted High

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Overview

CODE REASON EFFECT
Fault Code: 461
PID: S66
SPN: 725
FMI: 3
LAMP: Red
SRT: 

Ignition Control Module (Reference) Signal Circuit – Shorted High. High voltage detected at the ECM.

Engine will die or
not start.

Ignition Reference Signal Circuit
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Circuit Description

The ignition control module (ICM) is a distributorless ignition module that provides a signal to the coils and delivers high voltage to the spark plugs. The electronic control module (ECM) controls the ICM by providing ignition timing information.

Component Location

The ICM is located next to the ECM on the side of the engine.

Shop Talk

The ICM can
not detect whether there is a misfire or a bad spark plug. For the ICM to operate correctly, all connections
must be clean and tight. Cylinders 3 and 4 are especially critical to the proper operation of the ICM. A poor connection in either of these areas will cause the engine
not to start.

Cautions and Warnings

 WARNING 

EXTREMELY HIGH VOLTAGE. Do not touch any ignition wiring or component while the engine is operating unless an insulated tool is being used to prevent electrical shock and damage to the equipment.
 CAUTION 

To reduce the possibility of damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
 CAUTION 

To reduce the possibility of pin and harness damage, use the following test leads when taking a measurement:
Part Number 3822758 – male Deutsch™/AMP™/Metri-Pack™ test lead
Part Number 3823995 – male Weather Pack™ test lead.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Check the fault codes.  
  STEP 1A. Read the fault codes. Fault Code 461 active?
STEP 2. Check the ignition control module and wiring harnesses.  
  STEP 2A. Inspect the ICM and engine harness connector pins. Dirty or damaged pins?
  STEP 2B. Inspect the engine harness and ECM connector pins. Dirty or damaged pins?
  STEP 2C. Check for an open circuit. Less than 10 ohms?
  STEP 2D. Check for a short circuit to ground. Greater than 100k ohms?
  STEP 2E. Check for a short circuit from pin to pin. Greater than 100k ohms?
  STEP 2F. Inspect the OEM connector pins. Dirty or damaged pins?
  STEP 2G. Check for voltage supply to the ICM. 8 to 15-VDC on pin 27 or 30?
  STEP 2H. Check the 15-amp OEM fuse. Less than 10 ohms?
STEP 3. Clear the fault codes.  
  STEP 3A. Disable the fault code. Fault Code 461 inactive?
  STEP 3B. Clear the inactive fault codes. All fault codes cleared?

Guided Step 1 – Check the fault codes.

Guided Step 1A – Read the fault codes.

Conditions

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

Action

Read the fault codes.

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

Fault Code 461 active?
YES NO
No Repair No Repair

Guided Step 2 – Check the ignition control module and wiring harnesses.

Guided Step 2A – Inspect the ICM and engine harness connector pins.

Conditions

  • Turn keyswitch OFF.
  • Disconnected the engine harness from the ignition control module.

Action

Inspect the ignition control module and engine harness connector pins for the following:

  • Loose connector
  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Dirt or debris on or in the connector pins
  • Connector shell broken
  • Wire insulation damage
  • Damaged connector locking tab.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general inspection techniques, refer to Procedure 019-361 (Component Connector and Pin Inspection) in Section 19.

Dirty or damaged pins?
YES NO

Repair the damaged pins. Repair or replace the engine harness, or replace the ICM, whichever has the damaged pins.

 No Repair

Guided Step 2B – Inspect the engine harness and the ECM connector pins.

Conditions

  • Turn keyswitch OFF
  • Disconnect the engine harness connector 1 and connector 2 from the ECM
  • Disconnect the engine harness from the OEM harness at the 23 pin and 31 pin OEM connectors.

Action

Inspect the engine harness, OEM 23-pin, OEM 31-pin, and ECM connector pins for the following:

  • Loose connector
  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Dirt or debris on or in the connector pins
  • Connector shell broken
  • Wire insulation damage
  • Damaged connector locking tab.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general inspection techniques, refer to Procedure 019-361 (Component Connector and Pin Inspection) in Section 19.

Dirty or damaged pins?
YES NO

Repair the damaged pins. Repair or replace the engine harness, or replace the ECM, whichever has the damaged pins.

 No Repair

Guided Step 2C – Check for an open circuit.

Conditions

  • Turn keyswitch OFF
  • Disconnect the engine harness from the ICM.
  • Disconnect the engine harness connector 1 from the ECM.

Action

Check for an open circuit.

  • Measure the resistance between the ICM SIGNAL reference pin in the engine harness ECM connector to the ICM SIGNAL reference pin in the engine harness ICM connector.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general resistance measurement techniques, refer to Procedure 019-360 (Resistance Measurement Using a Multimeter) in Section 19.

SMALL | MEDIUM | LARGE

Less than 10 ohms?
YES NO
No Repair

Repair or replace the engine harness.

Guided Step 2D – Check for a short circuit to ground.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the engine harness from the ICM.
  • Disconnect the engine harness from connector 1 at the ECM.

Action

Check for a short circuit to ground as follows:

  • Measure the resistance from pin 11 of the ECM connector to engine block ground.

Resistance greater than 100k ohms?
YES NO
No Repair

Repair or replace the engine harness.

Guided Step 2E – Check for a short circuit from pin to pin.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the engine harness from the ICM.
  • Disconnect the engine harness from the OEM harness at the 23-pin and 31-pin OEM connectors.
  • Disconnect engine harness connector 1 and connector 2 from the ECM.

Action

Check for a short circuit from pin to pin.

  • Measure the resistance between the ICM SIGNAL reference pin in engine harness ECM connector 1 to all other pins in the connector.
  • Measure the resistance between the ICM SIGNAL reference pin in engine harness ECM connector 1 to all other pins in engine harness ECM connector 2.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general resistance measurement techniques, refer to Procedure 019-360 (Resistance Measurement Using a Multimeter) in Section 19.

SMALL | MEDIUM | LARGE

Greater than 100k ohms?
YES NO
No Repair

Repair or replace the engine harness.

Guided Step 2F – Inspect the OEM connector pins.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the engine harness from the 31-pin OEM connector.

Action

Inspect the OEM connector pins for the following.

  • Loose connector
  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Dirt or debris on or in the connector pins
  • Connector shell broken
  • Wire insulation damage
  • Damaged connector locking tab.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general inspection techniques, refer to Procedure 019-361 (Component Connector and Pin Inspection) in Section 19.

Dirty or damaged pins?
YES NO

Repair or replace the harness.

 No Repair

Guided Step 2G – Check the voltage supply to the ICM.

Conditions

  • Turn keyswitch OFF.
  • The engine harness disconnected from the 31-pin OEM connector.

Action

Check the voltage supplied to the ICM as follows:

  • Measure the voltage from pin 30 to ground on the vehicle side of the OEM connector.
  • Measure the voltage from pin 27 to ground on the vehicle side of the OEM connector.

Refer to the circuit diagram or wiring diagram for component pin identification.

8 to 15-VDC on pin 27 or 30?
YES NO
No Repair

Repair or replace the OEM harness.

Guided Step 2H – Check the 15-amp OEM fuse.

Conditions

  • Turn keyswitch OFF.

Action

Check the 15-amp fuse.

  • Measure the resistance across the 15-amp OEM fuse.

Refer to the circuit diagram or wiring diagram for component pin identification.

For general resistance measurement techniques, refer to Procedure 019-360 (Resistance Measurement Using a Multimeter) in Section 19.

Less than 10 ohms?
YES NO

Replace the ignition control module.
Refer to Procedure 019-105 (Ignition Control Module) in Section 19.

Replace the 15-amp fuse.

Guided Step 3 – Clear the fault codes.

Guided Step 3A – Disable the fault code.

Conditions

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

Action

Disable the fault code.

  • Start the engine and let it idle for 1 minute.
  • Use INSITE™ electronic service tool to verify Fault Code 461 is inactive.

Fault Code 461 inactive?
YES NO
No Repair

Return to the troubleshooting steps or contact a Cummins® Authorized Repair Location if all steps have been completed and checked again.

Guided Step 3B – Clear the inactive fault codes.

Conditions

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

Action

Clear the inactive fault codes.

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

All fault codes cleared?
YES NO
No Repair

Troubleshoot any remaining active fault codes.
Repair complete
Appropriate troubleshooting charts
Last Modified:  30-Sep-2008
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