ISM, ISMe, and QSM11 – Engine Brake Does Not Operate

Engine brake on/off switch is off

Turn on the switch.

Engine brake on/off switch or circuit is malfunctioning

Check the engine brake on/off switch and circuit. Refer to
the Troubleshooting and Repair Manual Electronic Control System, ISM and QSM11 Series Engines, Bulletin 3666266.
Refer to Procedures 019-034 (Engine Brake ON/OFF Switch) and 019-035 (Engine Brake ON/OFF Switch Circuit) in Section 19 in the Troubleshooting and Repair Manual CM870 Electronic Control System, ISM Engines, Bulletin 4021381.

Electronic fault codes active or high counts of inactive fault codes

View and troubleshoot the fault codes with INSITE™ electronic service tool. Refer to
the corresponding fault code in Section TF in the Troubleshooting and Repair Manual Electronic Control System ISM and QSM11 Series Engines, Bulletin 3666266.
Refer to the corresponding fault code in Section TF in the Troubleshooting and Repair Manual CM870 Electronic Control System ISM Engines, Bulletin 4021381.

No torque converter lockup signal. (Automatic Transmission Only)

Check the features and parameters-Transmission type, if automatic, continue. Use INSITE™ electronic service tool to change the transmission type to manual and check engine brake operation while the unit is stationary (the minimum MPH could possibly need to be changed to 0). If the brakes function correctly, change the transmission type back to automatic and consult the OEM or transmission manufacturer. If they do not function, continue to troubleshoot.

Engine brake solenoid, harness or connectors are loose, broken or have an open circuit

Check the engine brake circuit, solenoid, and harness connectors. Check the engine brake harness, solenoids, and grounding for continuity. Refer to
Procedure 019-136 (Engine Brake Harness) in Section 19 in the ISX and ISM CM871 and CM876 Electronic Control System Troubleshooting and Repair Manual, 4021560.
Refer to Procedure 020-024 (Engine Brake) in Section 20 in the ISM, ISMe and QSM11 Service Manual, Bulletin 3666322.

Clutch switch or circuit is malfunctioning

Check the clutch switch adjustment, switch, and circuit. Refer to Procedure 019-009 (Clutch Pedal Position Sensor) or 019-010 (Clutch Pedal Position Sensor Circuit) in Section 19 in the Troubleshooting and Repair Manual Electronic Control System ISM and QSM11 Series Engines, Bulletin 3666266.
Refer to Procedure 019-009 (Clutch Pedal Position Sensor) or 019-010 (Clutch Pedal Position Sensor Circuit) in Section 19 in the Troubleshooting and Repair Manual CM870 Electronic Control System ISM Engines, Bulletin 4021381.

Throttle position sensor is misadjusted or malfunctioning

Check throttle position sensor for proper adjustment and operation. Refer to Procedures 019-085 (Accelerator Pedal or Lever Position Sensor) and 019-086 (Accelerator Pedal or Lever Position Sensor Circuit) in Section 19 in the Troubleshooting and Repair Manual Electronic Control System ISM and QSM11 Series Engines, Bulletin 3666266.
Refer to Procedures 019-085 (Accelerator Pedal or Lever Position Sensor) and 019-086 (Accelerator Pedal or Lever Position Sensor Circuit) in Section 19 in the Troubleshooting and Repair Manual CM870 Electronic Control System ISM Engines, Bulletin 4021381.

Service brake pressure switch or circuit is malfunctioning

Check the service brake pressure switch and circuit. Refer to the OEM service manual.

Solenoid valve is malfunctioning

Check for voltage at the solenoid valve. Refer to the manufacturer’s instructions.

Solenoid valve filter screen is covered with debris

Remove the solenoid valve and clean or replace the screen. Refer to the manufacturer’s instructions.

Lubricating oil leak (internal)

Check the engine brake hose connections, the engine brake housing, and the jumper tube o-rings for oil leaks. Refer to the manufacturer’s instructions.

Engine brake lubricating oil supply line is restricted

Remove the oil supply line. Inspect the supply line for a restriction.

Engine brake adjustment is not correct

Adjust the engine brakes. Refer to Procedure 020-024 (Engine Brakes) in Section 20.