Pinpoint Test F: DTCs C1790/C1795 - LR/RR Air Suspension Air Spring Solenoid Output Circuit Failure

WARNING: This page is about a different car, the 2009 Mercury Grand Marquis and 2009 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Vehicle Dynamic Suspension for schematic and connector information.

Normal Operation

The vehicle dynamics module (VDM) controls the air spring solenoid by sending a voltage along circuit 1114 (BN/PK) for the LR solenoid and circuit 1115 (TN/WH) for the RR solenoid. This voltage engages the solenoid allowing air to either enter or leave the air spring. Ground for both solenoids is provided along circuit 57 (BK).

C1790 LR Air Suspension Air Spring Solenoid Output Circuit Failure - With the ignition in the RUN position and during a deflate (vent) or inflate (pump) activity, if the VDM detects an open, a short to voltage or a short to ground on the LR air spring solenoid output circuit, DTC C1790 will be set.
C1795 RR Air Suspension Air Spring Solenoid Output Circuit Failure - With the ignition in the RUN position and during a deflate (vent) or inflate (pump) activity, if the VDM detects an open, a short to voltage or a short to ground on the RR air spring solenoid output circuit, DTC C1795 will be set.

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors
Air spring solenoid
VDM

PINPOINT TEST F: DTCs C1790/C1795 - LR/RR AIR SUSPENSION AIR SPRING SOLENOID OUTPUT CIRCUIT FAILURE

NOTE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.

F1 CHECK CIRCUITS 1114 (BN/PK) AND 1115 (TN/WH) FOR AN OPEN
- Key in OFF position.
- Disconnect: VDM C2131b
- Disconnect: LR Air Spring Solenoid C4044
- Disconnect: RR Air Spring Solenoid C4045
- Measure the resistance between VDM C2131b-2, circuit 1115 (TN/WH) harness side and RR air spring solenoid C4045-1, harness side.
- Measure the resistance between VDM C2131b-3, circuit 1114 (BN/PK) harness side and LR air spring solenoid C4044-1, harness side.
- Are the resistances less than 5 ohms?
1. YES : Go to F2.
2. NO : REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
F2 CHECK CIRCUITS 1114 (BN/PK) AND 1115 (TN/WH) FOR A SHORT TO VOLTAGE
- Key in ON position.
- Measure the voltage between ground and:
  - VDM C2131b-3, circuit 1114 (BN/PK), harness side.
  - VDM C2131b-2, circuit 1115 (TN/WH), harness side.
- Is any voltage present?
1. YES : REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
2. NO : Go to F3.
F3 CHECK CIRCUITS 1114 (BN/PK) AND 1115 (TN/WH) FOR A SHORT TO GROUND
- Key in OFF position.
- Measure the resistance between ground and:
  - VDM C2131b-3, circuit 1114 (BN/PK), harness side.
  - VDM C2131b-2, circuit 1115 (TN/WH), harness side.
- Are the resistances greater than 10,000 ohms?
1. YES : Go to F4.
2. NO : REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
F4 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between ground and:
  - LR air spring solenoid C4044-2, circuit 57 (BK), harness side.
  - RR air spring solenoid C4045-2, circuit 57 (BK), harness side.
- Are the resistances less than 5 ohms?
1. YES : Go to F5.
2. NO : REPAIR circuit 57 (BK). CLEAR the DTCs. REPEAT the self-test.
F5 CHECK THE LR AND RR AIR SPRING SOLENOIDS
- Key in OFF position.
- Measure the resistance between:
  - LR air spring solenoid C4044-1, component side, and C4044-2, component side.
  - RR air spring solenoid C4045-1, component side, and C4045-2, component side.
- Are the resistances between 10 and 17 ohms?
1. YES : INSTALL a new VDM. REFER to Vehicle Dynamics Module (VDM) . CLEAR the DTCs. REPEAT the self-test.
2. NO : INSTALL a new LR or RR air spring solenoid. REFER to Air Spring Solenoid Valve . CLEAR the DTCs. REPEAT the self-test.