Cummins ISX11.9 CM2250 – Service Manual Engine Brake – One or More Cylinders Braking with Power Switch Off

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF in the Fault Code Troubleshooting Manual, Bulletin
4022225 for fault code troubleshooting.

Engine brake enable circuit is malfunctioning

Check the engine brake enable circuit. Refer to
Procedure 019-034 in Section 19
.

Engine brake on/off switch or circuit is malfunctioning

Check the engine brake on/off switch and circuit. Refer to Procedure 019-034 and
Procedure 019-035 in Section 19.

Engine brake adjustment is not correct

Adjust the engine brakes. Refer to
Procedure 020-024 in Section 20
.

Solenoid valve o-ring seals are leaking

Remove the solenoid valve and inspect the top and bottom o-rings. Replace the o-rings if necessary. Refer to
Procedure 020-024 in Section 20
.

Solenoid valve is malfunctioning

Check for voltage at the solenoid valve. Refer to
Procedure 020-012 in Section 20.

Solenoid valve is stuck in the on position

Replace the solenoid valve. Refer to
Procedure 020-012 in Section 20
.