Pinpoint Test J: DTC U1901

Anti-Lock Control

Pinpoint Tests

Pinpoint Test J: DTC U1901

Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number

Normal Operation

The ABS module communicates with the stability control sensor cluster along the secondary bus, circuits VCA23 (BU/WH) and VCA24 (GN/OG).

- DTC U1901 (CAN Network #2 Communication Bus Fault) - Receive Error - If the ABS module does not receive an expected message from the stability control sensor cluster or the message received does not agree with other sensor inputs, DTC U1901 will be set.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Stability control sensor cluster
- ABS module



PINPOINT TEST J: DTC U1901

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

-------------------------------------------------
J1 CHECK CIRCUITS VCA23 (BU/WH) AND VCA24 (GN/OG) FOR A SHORT TO VOLTAGE


NOTE: The battery and battery tray need to be removed to access the ABS module connector.

NOTE: The battery must be connected to carry out this test.

- Ignition OFF.
- Disconnect: ABS Module C135.
- Disconnect: Stability Control Sensor Cluster C3037.
- Ignition ON.
- Measure the voltage between ground and:
- stability control sensor cluster C3037-3, circuit VCA23 (BU/WH), harness side.
- stability control sensor cluster C3037-4, circuit VCA24 (GN/OG), harness side.




- Is any voltage present?

Yes
REPAIR the affected circuit(s). CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.

No
GO to J2.

-------------------------------------------------
J2 CHECK CIRCUITS VCA23 (BU/WH) AND VCA24 (GN/OG) FOR A SHORT TO GROUND


- Ignition OFF.
- Measure the resistance between ground and:
- stability control sensor cluster C3037-3, circuit VCA23 (BU/WH), harness side.
- stability control sensor cluster C3037-4, circuit VCA24 (GN/OG), harness side.




- Are the resistances greater than 10,000 ohms?

Yes
GO to J3.

No
REPAIR the affected circuit(s). CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.

-------------------------------------------------
J3 CHECK CIRCUITS VCA23 (BU/WH) AND VCA24 (GN/OG) FOR AN OPEN


- Measure the resistance between ABS module C135, harness side and stability control sensor cluster C3037, harness side as indicated in the following chart:








- Are the resistances less than 5 ohms?

Yes
GO to J4.

No
REPAIR the affected circuit(s). CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.

-------------------------------------------------
J4 CHECK CIRCUITS VCA23 (BU/WH) AND VCA24 (GN/OG) FOR A SHORT TOGETHER


- Measure the resistance between stability control sensor cluster C3037-3, circuit VCA23 (BU/WH), harness side and stability control sensor cluster C3037-4, circuit VCA24 (GN/OG), harness side.




- Is the resistance greater than 10,000 ohms?

Yes
GO to J5.

No
REPAIR the affected circuit(s). CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.

-------------------------------------------------
J5 CHECK THE SENSOR CLUSTER MODULE


- Install a known good sensor cluster. Refer to Stability Control Sensor Cluster Service and Repair.
- Connect: ABS Module C135.
- Carry out the ABS module self-test. Retrieve and record any ABS module DTCs.
- Was DTC U1901 retrieved?

Yes
INSTALL the original sensor cluster. INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module Service and Repair. CALIBRATE the ABS module. FOLLOW the scan tool directions for the IVD Initialization sequence. CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.

No
Fault corrected. CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.

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