C1800 - FAULT CODE - OBD2

C1800 Code failures by brands

C1800 FORD, LINCOLN, MERCURY: AIR SUSPENSION RESERVOIR SOLENOID CIRCUIT FAILURE

Description of DTC code C1800

The Air Suspension System uses air springs that are enclosed in a rubber/plastic membrane. The air reservoir inflates or deflates so that the ride height of the vehicle is maintained. The pneumatic reservoir solenoid is a valve that is responsible for regulating the amount of air in the reservoir, depending on the height of the vehicle concerning the ground. This solenoid is located at the top of the air springs and is connected to the compressor by employing a pressure line.

The air suspension reservoir solenoid has an electrical line through which a signal is sent to it to open or close. In this way, the solenoid lets air in or releases air from the shock absorber assembly to bring the car up to its normal height from the ground. The solenoid is constantly monitored by the VDM (Vehicle Dynamic Module). If the VDM detects that the solenoid does not meet factory specifications, the diagnostic code C1800 OBD2 will be set.

Symptoms of fault code C1800

Check Engine light on.
ABS (Anti-Lock Brake System) warning light illuminated.

Causes of OBD2 C1800

The reasons for the C1800 OBDII fault code being stored are:

The Air Suspension Reservoir Solenoid may have bad wiring.
Air Suspension Reservoir Solenoid circuit may have poor connections.
The Air Suspension Reservoir Solenoid could be defective.
The Vehicle's Dynamic Module may be damaged.

Possible solutions of the DTC code C1800

In order to troubleshoot DTC C1800 OBD2 you must do the following:

Consult the Technical Service Bulletins.
Inspect all the wires of the air suspension reservoir solenoid circuit. If any of these components are found to be defective due to burns or wear, make the appropriate repairs.
Check air suspension reservoir solenoid circuit connections for excessive corrosion damage or terminals that prevent efficient connections. Repair as required.
Measure the resistance of the air suspension reservoir solenoid and compare it to the manufacturer's specifications. A resistance outside the stated range indicates solenoid failure and should be replaced.