ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – Engine Brake – Low Retarding Power or Slow to Activate

Interview the operator to verify the complaint

Refer to Procedure t00-004 Driveability-General Information, the Driveability/Low-Power Customer Complaint Form, and the Driveability Checklist at the end of Section TS. Follow the instructions on the forms before continuing with this tree.

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF in the Troubleshooting and Repair Manual, CM850 Electronic Control System, ISC and ISL Engines, Bulletin 4021416, or Troubleshooting and Repair Manual, Electronic Control System, ISC, QSC8.3 and ISL Engines, Bulletin 3666271.

Programmable parameters or selected features are not correct

Check the programmable parameters and the selected features with an electronic service tool. Set the parameters and features again if necessary. Refer to Section 1 in the Operation and Maintenance Manual, ISC, ISC^e, ISL Engines, Bulletin 4021428 or Operation and Maintenance Manual, QSC8.3 and QSL9 Engines, Bulletin 4021518.

Engine is cold

Allow the engine to warm to operating temperature. If the engine will not reach operating temperature, refer to the Coolant Temperature Below Normal symptom tree.

Engine brake adjustment is not correct

Adjust the engine brakes. Refer to Procedure 020-004.

Engine brake harness connectors are loose or broken

Check the engine brake harness connectors. Check the engine brake harness for continuity.

Air in the lubricating oil system

Check the oil level. If level is high, check for a cracked suction tube. Refer to Procedure 007-025.

Lubricating oil leak (internal)

Check the engine brake control valve and the engine brake piston. Refer to Procedures 020-004.

Engine brake solenoid(s) is malfunctioning

Refer to the Troubleshooting and Repair Manual, CM850 Electronic Control System, ISC and ISL Engines, Bulletin 4021416, or Troubleshooting and Repair Manual, Electronic Control System, ISC, QSC8.3 and ISL Engines, Bulletin 3666271.

Engine brake control valve(s) is malfunctioning

Check the engine brake control valve(s). Replace the engine brake control valve(s) if necessary. Refer to Procedure 020-004.

Engine brake lubricating oil passage is restricted

Check the engine brake assembly for restriction. Refer to Procedure 020-004.

Turbocharger is malfunctioning

Monitor the turbocharger boost pressure with an electronic service tool. Refer to the Engine Performance Troubleshooting tree in Section TT.