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Electronic Control System Gas Plus Engines – FAULT CODE 1652

Spark Voltage on Multiple Cylinders – Data erratic, intermittent or incorrect.

Overview

CODE REASON EFFECT
Fault Code: 1652
PID: None
SPN: None
FMI: 2
LAMP: Amber
SRT: 

Spark Voltage on Multiple Cylinders – Data erratic, intermittent or incorrect.

None – information for short or open circuit in the ignition harness spark signal lines.

Ignition Timing Signal Circuit
SMALL | MEDIUM | LARGE

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. The ICM is capable of misfire and spark voltage detection.

Component Location

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

Shop Talk

This fault code is designed to inform the technician a potential problem with the ignition harness or ICM. The most probable cause for this fault code to occur will be from an ignition harness short or open.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Check the fault codes.  
  STEP 1A. Check for an inactive fault code. Fault Code 1652 inactive?
STEP 2. Check the ICM and ignition harness.  
  STEP 2A. Inspect the ICM ignition harness connector pins. Dirty or damaged pins?
  STEP 2B. Check for an open circuit in the ignition harness. Less than 10 ohms?
  STEP 2B-1. Check for an open circuit in the ignition harness.
  STEP 2C. Check for a pin short circuit to ground. Greater than 100k ohms?
  STEP 2D. Check for a pin to pin short circuit in the ignition harness. Greater than 100k ohms?
  STEP 2E. Check for an inactive fault code. Fault Code 1652 inactive?
STEP 3. Clear the fault code.  
  STEP 3A. Disable the fault code. Fault Code 1652 inactive?
  STEP 3B. Clear the inactive fault codes. All fault codes cleared?

Guided Step 1 – Check the fault codes.

Guided Step 1A – Check for an inactive fault code.

Conditions

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

Action

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

Fault Code 1652 inactive?
YES NO
No Repair No Repair
Procedure 019-362

Guided Step 2 – Check the ICM ignition harness.

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

Conditions

  • Turn keyswitch OFF
  • Disconnect the ignition harness connector C1 and connector C2 from the ICM.

Action

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

For general inspection techniques, refer to Component Connector and Pin Inspection, Procedure 019-361.

Dirty or damaged pins?
YES NO

A defective connection has been detected in the ICM or ignition harness connectors.

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

  • Flush the dirt, debris, or moisture from the connector pins using electronic contact cleaner, Part Number 3824510.
  • Replace the ignition harness. Refer to Procedure 013-037 in the Troubleshooting and Repair Manual C Gas, C Gas Plus, and L Gas Plus Engines, Bulletin 3666206.
  • Replace the ICM. Refer to Procedure 019-105.
 No Repair

Guided Step 2B – Check for an open circuit in the ignition harness.

Conditions

  • Turn keyswitch OFF
  • Disconnect ignition harness connector C2 from the ICM.
  • Disconnect ignition harness from all coils.

Action

  • Measure the resistance between the ignition harness ICM connector C2 coil SIGNAL pin and the ignition harness coil connector SIGNAL pin.
  • Measure the resistance between the ignition harness ICM connector C2 CD voltage pin and the ignition harness coil connector CD voltage pin.

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

For general resistance measurement techniques, refer to Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360

Less than 10 ohms?
YES NO
No Repair

An open signal circuit has been detected in the ignition harness.

Repair or replace the ignition harness.

  • Replace the ignition harness. Refer to Procedure 013-037 in the Troubleshooting and Repair Manual C Gas, C Gas Plus, and L Gas Plus Engines, Bulletin 3666206.

Guided Step 2B-1 – Check for an open circuit in the ignition harness.

Conditions

  • Turn keyswitch OFF
  • Disconnect ignition harness connector C2 from the ICM.
  • Disconnect ignition harness from all coils.

Action

  • Measure the resistance between the ignition harness ICM connector spark RETURN SIGNAL pin and the ignition harness coil connector RETURN SIGNAL pins.

Note: All spark return signal wires in the ignition harness are tied together. This way there will be continuity through each spark signal pin of each coil to the main spark return signal wire at the ignition harness connector C2. If one of the spark signal circuits is found to be open, then the ICM will think that the engine is misfiring when it is not.

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

For general resistance measurement techniques, refer to Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360

Less than 10 ohms?
YES NO
No Repair

A open signal circuit has been detected in the ignition harness.

Repair or replace the ignition harness.

  • Replace the ignition harness. Refer to Procedure 013-037 in the Troubleshooting and Repair Manual C Gas, C Gas Plus, and L Gas Plus Engines, Bulletin 3666206.

Guided Step 2C – Check for a pin short to ground.

Conditions

  • Turn keyswitch OFF
  • Disconnect the ignition harness connector C2 from the ICM
  • Disconnect the ignition harness from all coils.

Action

  • Measure the resistance between the CD voltage pin at the coil connector and engine block ground.
  • Measure the resistance between the coil SIGNAL pin at the coil connector and engine block ground.
  • Measure the resistance between the spark SIGNAL pin at the coil connector and engine block ground.

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

For general resistance measurement techniques, refer to Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360

Greater than 100k ohms?
YES NO
No Repair

A pin to ground short circuit has been detected in the ignition harness.

Repair or replace the ignition harness.

  • Replace the ignition harness. Refer to Procedure 013-037 in the Troubleshooting and Repair Manual C Gas, C Gas Plus, and L Gas Plus Engines, Bulletin 3666206.

Guided Step 2D – Check for a pin to pin short circuit in the ignition harness.

Conditions

  • Turn keyswitch OFF
  • Disconnect ignition harness connector C2 from the ICM.
  • Disconnect ignition harness from the ignition coils.

Action

  • Measure the resistance between the CD voltage pin in the ignition harness ICM connector C2 and all other pins in the ignition harness connector C2.
  • Measure the resistance between the spark RETURN SIGNAL pin in the ignition harness ICM connector C2 and all other pins in the ignition harness connector C2.
  • Measure the resistance between each coil SIGNAL pin in the ignition harness ICM connector C2 and all other pins in the ignition harness connector C2.

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

For general resistance measurement techniques, refer to Resistance Measurements Using a Multimeter and Wiring Diagram, Procedure 019-360

Greater than 100k ohms?
YES NO
No Repair

A pin to pin short circuit has been detected in the ignition harness.

Repair or replace the ignition harness.

  • Replace the ignition harness. Refer to Procedure 013-037 in the Troubleshooting and Repair Manual C Gas, C Gas Plus, and L Gas Plus Engines, Bulletin 3666206.

Guided Step 2E – Check for an inactive fault code.

Conditions

  • Connect all components
  • Turn keyswitch ON
  • Start engine and let idle
  • Connect INSITE™ electronic service tool.

Action

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

Fault Code 1652 inactive?
YES NO

Note: The removal and installation of the connectors corrected the failure.
  • Replace the ICM. Refer to Procedure 019-105.

Guided Step 3 – Clear the fault codes.

Guided Step 3A – Disable the fault code.

Conditions

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

Action

  • Start the engine and let it idle for one minute.
  • Use INSITE™ electronic service tool to verify that the fault code is inactive.

Fault Code 1652 inactive?
YES NO
No Repair No Repair

Guided Step 3B – Clear the inactive fault codes.

Conditions

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

Action

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

All fault codes cleared?
YES NO
No Repair No Repair
Repair complete
Appropriate troubleshooting steps
Last Modified:  30-Sep-2004
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