Pinpoint Test E: DTCs C1278 And C1963
Anti-Lock Control
Pinpoint Tests
Pinpoint Test E: DTCs C1278 and C1963
Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number
Normal Operation
The Steering Angle Sensor Module (SASM) monitors the steering wheel position when the slotted-wheel in the sensor passes through the optical field of the sensor.
Fused ignition voltage is supplied to the SASM from Smart Junction Box (SJB) fuse 34 (5A) along circuit CBP34 (VT/BN). Ground for the sensor is provided along circuit GD115 (BK/GY). The steering wheel angle (in degrees) is sent to the ABS module along the High Speed Controller Area Network (HS-CAN) bus, circuits VDB04 (WH/BU) and VDB05 (WH).
- DTC C1278 (Steering Wheel Angle 1 and 2 Circuit Faulted) - If during normal operation or the ABS module on-demand self test, the ABS module does not receive the steering wheel rotation sensor input or if the input received does not agree with the input from other sensors, DTC C1278 will be set. Also, a loss of sensor power or ground will cause DTC C1278 to set.
- DTC C1963 (Stability Control Inhibit Warning) - Once every key-cycle the ABS module will determine the straight-ahead or center position of the steering wheel by monitoring the steering wheel rotation sensor while the vehicle is being driven. If the vehicle reaches a speed of 75 km/h (47 mph) without finding the center position or if 30 seconds has passed since the initial drive-off without finding the center position, DTC C1963 will set.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- SASM
PINPOINT TEST E: DTCs C1278 AND C1963
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
NOTICE: Overtightening of the Steering Angle Sensor Module (SASM) fasteners may deform or damage the sensor housing, possibly resulting in faulty operation.
NOTE: Make sure that the SASM is mounted securely to the column with 2 fasteners. A loose sensor or missing fastener may result in incorrect sensor operation. Make sure that the sensor connector is mated securely to the harness connector. Before proceeding with electrical testing, make sure that the vehicle battery is fully charged.
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E1 CHECK THE SASM FOR DTCs
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - SASM.
- Retrieve and record any SASM DTCs.
- Are any DTCs retrieved?
Yes
GO to the Steering Angle Sensor Module (SASM) DTC Chart. Steering Angle Sensor Module (SASM) DTC Chart
No
If the SASM does not respond to the scan tool, REFER to Information Bus to diagnose the HS-CAN communications concern.
If no DTCs were retrieved from the SASM self-test, GO to E2.
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E2 CALIBRATE THE ABS MODULE
- Enter the following diagnostic mode on the scan tool: IVD Initialization Sequence.
- Carry out the IVD Initialization sequence following the scan tool instructions.
- Does the IVD Initialization sequence indicate a fault?
Yes
DRIVE the vehicle at a speed greater than 40 km/h (25 mph). REPEAT the ABS module self-test. GO to the ABS Module DTC Chart to diagnose the DTC retrieved. ABS Module DTC Chart
No
GO to E3.
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E3 MONITOR THE SASM PID (SWA POS)
- Enter the following diagnostic mode on the scan tool: DataLogger - ABS Module.
- Monitor the SWA POS PID while rotating the steering wheel clockwise and counterclockwise very slowly.
- Does the PID move in intervals of 1 degree?
Yes
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. CARRY OUT the ABS module self-test with the brake pedal not applied.
No
INSTALL a new SASM. REFER to Steering Angle Sensor Module (SASM) Service and Repair. CLEAR the DTCs. CARRY OUT the ABS module self-test with the brake pedal not applied.
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