Pinpoint Test E: DTC C1770

Vehicle Dynamic Suspension

Pinpoint Tests

Pinpoint Test E: DTC C1770

Refer to Wiring Diagram Set 41, Vehicle Dynamic Suspension for schematic and connector information. Diagrams By Number

Normal Operation

When venting of the rear air suspension system is necessary, the Vehicle Dynamics Module (VDM) sends voltage to the vent solenoid along circuit 421 (PK). This voltage engages the solenoid which then vents the system. The solenoid is provided a ground along circuit 57 (BK). The vent solenoid is part of the air suspension compressor assembly and is serviced as such.

- DTC C1770 (Air Suspension Vent Solenoid Output Circuit Failure) - With the ignition in the RUN position and during a deflate (vent) activity, if the VDM detects an open, a short to voltage or a short to ground on the vent solenoid output circuit, DTC C1770 will be set.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- VDM
- Air suspension compressor



PINPOINT TEST E: DTC C1770

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

-------------------------------------------------
E1 CHECK CIRCUIT 57 (BK) FOR AN OPEN


- Measure the resistance between the air compressor C1179-3, circuit 57 (BK), harness side and ground.




- Is the resistance greater than 5 ohms?

Yes
REPAIR circuit 57 (BK). CLEAR the DTC. REPEAT the self-test.

No
GO to E2.

-------------------------------------------------
E2 CHECK CIRCUIT 421 (PK) FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: VDM C2131a.
- Disconnect: Air Compressor C1179.
- Ignition ON.
- Measure the voltage between the air compressor C1179-4, circuit 421 (PK), harness side and ground.




- Is any voltage present?

Yes
REPAIR circuit 421 (PK). CLEAR the DTC. REPEAT the self-test.

No
GO to E3.

-------------------------------------------------
E3 CHECK CIRCUIT 421 (PK) FOR A SHORT TO GROUND


- Ignition OFF.
- Measure the resistance between the air compressor C1179-4, circuit 421 (PK), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to E4.

No
REPAIR circuit 421 (PK). CLEAR the DTC. REPEAT the self-test.

-------------------------------------------------
E4 CHECK CIRCUIT 421 (PK) FOR AN OPEN


- Measure the resistance between the VDM C2131a-7, circuit 421 (PK), harness side and air compressor C1179-4, circuit 421 (PK), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to E5.

No
REPAIR circuit 421 (PK). CLEAR the DTC. REPEAT the self-test.

-------------------------------------------------
E5 CHECK THE AIR COMPRESSOR VENT SOLENOID


- Measure the resistance between the air compressor connector C1179-4, component side, and connector C1179-3, component side.
- Is the resistance between 30 and 35 ohms?

Yes
INSTALL a new VDM. REFER to Vehicle Dynamics Module (VDM) Service and Repair. CLEAR the DTCs. REPEAT the self-test.

No
INSTALL a new air compressor. REFER to Air Suspension Compressor Service and Repair. CLEAR the DTC. REPEAT the self-test.

-------------------------------------------------