FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Mercury >> 2009 >> Milan FWD V6-3.0L >> Repair and Diagnosis >> Brakes and Traction Control >> Antilock Brakes / Traction Control Systems >> Testing and Inspection >> Pinpoint Tests >> Pinpoint Test F: DTCs C1277, C1278 and C1963

Pinpoint Test F: DTCs C1277, C1278 and C1963




Anti-Lock Control

Pinpoint Tests

Pinpoint Test F: DTCs C1277, C1278 and C1963

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

Normal Operation

A toothed-wheel is attached to the steering column behind the clockspring and the steering wheel rotation sensor is attached to the RH side of the steering column just above the ignition lock cylinder. As the steering wheel is turned, the toothed-wheel passes through the magnetic field of the steering wheel rotation sensor indicating which direction and how fast the steering wheel is being turned. This information is sent to the ABS module and is used to help determine if the Electronic Stability Control (ESC) system needs to be activated.

The steering wheel position (in degrees) is sent to the ABS module along circuit VCA41 (VT/GN) and circuit VCA42 (VT/OG). Voltage is supplied to the sensor by the ABS module along circuit CCA40 (GY/BU) and ground is provided by the ABS module along circuit RCA40 (BN/VT).

- DTC C1277 Steering Wheel Angle 1 and 2 Circuit Failure - If during normal operation or the ABS module on-demand self test, the ABS module detects an open circuit, short to voltage or short to ground along circuits VCA41 (VT/GN) or VCA42 (VT/OG), DTC C1277 will be set. An internal failure of the steering wheel rotation sensor may also cause DTC C1277 to set.
- DTC C1278 Steering Wheel Angle 1 and 2 Signal 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 C1277 will be set.
- DTC C1963 Stability Assist Inhibit Warning - If conditions exist during normal operation that prevents the ESC system from operating, DTC C1963 will be set. This DTC is usually set due to the steering wheel rotation sensor or the stability control sensor cluster being damaged or installed incorrectly.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Steering wheel rotation sensor incorrectly installed
- Steering wheel rotation sensor
- ABS module



PINPOINT TEST F: DTCs C1277, 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.

-------------------------------------------------
F1 MONITOR THE STEERING POSITION SENSOR PID (SWA POS)


- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - ABS.
- Monitor the SWA POS PID while rotating the steering wheel clockwise and counterclockwise very slowly, from lock to lock.
- Do the PIDs change in intervals of 1.5 degrees and show a 360 degree increase for each complete revolution of the steering wheel?

Yes
GO to F2.

No
GO to F3.

-------------------------------------------------
F2 CHECK FOR RETURNING DTCs


- Clear the ABS module DTCs.
- Drive the vehicle above 48 km/h (30 mph) with input from the steering wheel.
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module.
- Retrieve and record any ABS module DTCs.
- Are any ABS module DTCs present?

Yes
If DTCs C1963, C1277 or C1278 are present, GO to F3.

For all other DTCs, GO to the ABS Module DTC Chart. [1][2]Diagnostic Trouble Code Descriptions

No
The condition is not present at this time. INSPECT the rotation sensor and the toothed-wheel for cracks, looseness and foreign material. REPAIR or INSTALL new as necessary. TEST the system for normal operation.

-------------------------------------------------
F3 CHECK THE STEERING WHEEL ROTATION SENSOR CONDITION AND INSTALLATION


- Inspect the steering wheel rotation sensor and toothed-wheel for damage and correct installation. Refer to Steering Wheel Rotation Sensor Service and Repair.
- Are the sensor and toothed-wheel installed correctly and undamaged?

Yes
GO to F4.

No
REINSTALL or INSTALL new as necessary. CARRY OUT the IVD Initialization sequence. FOLLOW the scan tool directions. TEST the system for normal operation.

-------------------------------------------------
F4 CHECK THE VOLTAGE TO THE STEERING WHEEL ROTATION SENSOR


NOTE: The steering wheel rotation sensor is located on the RH side of the multifunction switch.

- Ignition OFF.
- Disconnect: Steering Wheel Rotation Sensor C226.
- Ignition ON.
- Measure the voltage between steering wheel rotation sensor C226-4, circuit CCA40 (GY/BU), harness side and ground.




- Is the voltage greater than 9.5 volts?

Yes
GO to F5.

No
REPAIR circuit CCA40 (GY/BU). CLEAR the DTCs. CARRY OUT the IVD Initialization sequence. FOLLOW the scan tool directions. REPEAT the self-test.

-------------------------------------------------
F5 CHECK CIRCUIT RCA40 (BN/VT) FOR AN OPEN


- Measure the voltage between steering wheel rotation sensor C226-4, circuit CCA40 (GY/BU), harness side and steering wheel rotation sensor C226-1, circuit RCA40 (BN/VT), harness side.




- Is the voltage greater than 9.5 volts?

Yes
GO to F6.

No
REPAIR circuit RCA40 (BN/VT). CLEAR the DTCs. CARRY OUT the IVD Initialization sequence. FOLLOW the scan tool directions. REPEAT the self-test.

-------------------------------------------------
F6 CHECK CIRCUIT VCA41 (VT/GN) FOR AN OPEN


- Measure the voltage between steering wheel rotation sensor C226-2, circuit VCA41 (VT/GN), harness side and steering wheel rotation sensor C226-1, circuit RCA40 (BN/VT), harness side.




- Is the voltage between 4.75 volts and 5.25 volts?

Yes
GO to F7.

No
REPAIR circuit VCA41 (VT/GN). CLEAR the DTCs. CARRY OUT the IVD Initialization sequence. FOLLOW the scan tool directions. REPEAT the self-test.

-------------------------------------------------
F7 CHECK CIRCUIT VCA42 (VT/OG) FOR AN OPEN


- Measure the voltage between steering wheel rotation sensor C226-3, circuit VCA42 (VT/OG), harness side and steering wheel rotation sensor C226-1, circuit RCA40 (BN/VT), harness side.




- Is the voltage between 4.75 volts and 5.25 volts?

Yes
GO to F8.

No
REPAIR circuit VCA42 (VT/OG). CLEAR the DTCs. CARRY OUT the IVD Initialization sequence. FOLLOW the scan tool directions. REPEAT the self-test.

-------------------------------------------------
F8 CHECK THE STEERING POSITION SENSOR CIRCUITS FOR AN OPEN


NOTE: The degas bottle may need to be positioned aside to access the ABS module connector.

- Ignition OFF.
- Disconnect: ABS Module C135.
- Disconnect: Steering Wheel Rotation Sensor C226.
- Measure the resistance between ABS module C135, harness side and steering wheel rotation sensor C226, harness side using the following table:









- Are the resistances less than 5 ohms?

Yes
GO to F9.

No
REPAIR the affected circuit(s). CLEAR the DTCs. CARRY OUT the IVD Initialization sequence. FOLLOW the scan tool directions. REPEAT the self-test.

-------------------------------------------------
F9 CHECK THE STEERING POSITION SENSOR CIRCUITS FOR A SHORT TO VOLTAGE


- Ignition ON.
- Measure the voltage between:
- ABS module C135-5, circuit CCA40 (GY/BU), harness side and ground.
- ABS module C135-9, circuit VCA42 (VT/OG), harness side and ground.
- ABS module C135-40, circuit RCA40 (BN/VT), harness side and ground.
- ABS module C135-41, circuit VCA41 (VT/GN), harness side and ground.




- Is any voltage present?

Yes
REPAIR the affected circuit(s). CLEAR the DTCs. CARRY OUT the IVD Initialization sequence. FOLLOW the scan tool directions. REPEAT the self-test.

No
GO to F10.

-------------------------------------------------
F10 CHECK THE STEERING POSITION SENSOR CIRCUITS FOR A SHORT TO GROUND


- Ignition OFF.
- Measure the resistance between:
- ABS module C135-5, circuit CCA40 (GY/BU), harness side and ground.
- ABS module C135-9, circuit VCA42 (VT/OG), harness side and ground.
- ABS module C135-40, circuit RCA40 (BN/VT), harness side and ground.
- ABS module C135-41, circuit VCA41 (VT/GN), harness side and ground.




- Are the resistances greater than 10,000 ohms?

Yes
If sent here because DTC C1963 is present, Go To Pinpoint Test G. Pinpoint Test G: DTCs B2741, C1279, C1280, C1281, C1282, C1963, C2769, C2770, C2777, C2778 and U1901

INSTALL a new steering wheel rotation sensor. REFER to Steering Wheel Rotation Sensor Service and Repair. CLEAR the DTCs. REPEAT the self-test.

No
REPAIR the affected circuit(s). CLEAR the DTCs. CARRY OUT the IVD Initialization sequence. FOLLOW the scan tool directions. REPEAT the self-test.

-------------------------------------------------
pro multis Credits:Operation CHARM About Operation CHARM