C1735: OBD-II code C1735 flags the air-suspension compressor relay circuit shorted to battery voltage — the compressor may run continuously or refuse to shut off.

Symptoms

• The 'Service Ride Control' warning is displayed and the vehicle may sag at one or more corners as levelling is disabled.
• The air suspension compressor may run continuously, overheat, or fail to shut off after the vehicle is levelled.
• The compressor fuse may blow repeatedly, or the compressor motor may burn out from excessive runtime.

Common causes

• A shorted compressor relay stuck closed, feeding continuous battery voltage to the compressor motor.
• A chafed compressor relay control wire touching a battery-voltage source, causing the relay to energise continuously.
• A failed suspension control module driver stuck in the on state, keeping the relay energised.

What to do?

Locate the compressor relay in the underhood fuse box or trunk and swap in a known-good relay. If the fault clears, replace the relay. If the fault persists, inspect the relay control wiring for a short to B+. If wiring is good, the suspension control module driver has failed and the module needs replacement.