Engine brake on/off switch or circuit is malfunctioning

Check the engine brake on/off switch and circuit. Refer to Procedure 019-035 in Section 19 of the CELECT Plus™ Systems Troubleshooting and Repair Manual, Bulletin 3666130, or the CELECT™ Systems Troubleshooting and Repair Manual, Bulletin 3666084.

Clutch switch is malfunctioning

Check the clutch switch adjustment and the clutch switch circuit. Refer to the OEM service manual.

Engine brake throttle switch is malfunctioning

Check the engine brake throttle switch (fuel pump switch ).

Service brake pressure switch or circuit is malfunctioning

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

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 the OEM service manual.

Solenoid valve is malfunctioning

Check for voltage at the solenoid valve. Refer to Procedure 020-024 in Section 20

Inner control valve spring is broken or the control valve is stuck in the on position

Inspect the inner control valve springs and the control valve. Refer to the OEM service manual and the C-Brake Troubleshooting and Repair Manual, Bulletin 3810473. Replace the springs or control valve as necessary.