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C1234




Anti-Lock Control - Non-Hybrid

Pinpoint Test D: DTC C1233 (LF), C1234 (RF), C1235 (RR) or C1236 (LR)

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

Normal Operation

The wheel speed sensor and sensor ring generate a square wave signal to the ABS module that is proportional to wheel speed. The ABS module compares wheel speed inputs from all wheel speed sensors to determine an impending wheel lockup. Incorrect tire size can set these DTCs as well.

Voltage and ground signals are supplied to the wheel speed sensors from the ABS module. A difference in wheel speeds possibly caused by damaged wheel speed sensor rings, mismatched wheel sizes, driving on flat tires, an excessive wheel speed sensor air gap or a damaged tone ring causes DTC C1233, C1234, C1235 or C1236 to set. Also an open or a short to voltage or ground in the sensor circuits causes the appropriate DTC to set.





This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Mismatched tire sizes

- Wheel speed sensor tone ring

- Wheel speed sensor

- Wheel bearing

- ABS module

PINPOINT TEST D : DTC C1233 (LF), C1234 (RF), C1235 (RR) OR C1236 (LR)

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

D1 CHECK THE DTCs FROM THE SELF TEST

- Connect the scan tool.

- Check the recorded results from the ABS self-test.

Is DTC C1145, C1155, C1165 or C1175 present?

Yes
GO to Pinpoint Test C Pinpoint Test C: DTC C1145 (RF), C1155 (LF), C1165 (RR) Or C1175 (LR).

No
GO to D2.

D2 CHECK THE TIRES SIZE AND PRESSURE

NOTE: Make sure all 4 tires are worn evenly.

- Verify that all tires are the correct size as indicated on the Vehicle Certification label.

Are the tires the correct size and correctly inflated as specified on the Vehicle Certification label?

Yes
GO to D3.

No
INSTALL the correct size tire or adjust tire pressure as necessary.

D3 INSPECT THE WHEEL SPEED SENSOR MOUNTING

- Ignition OFF.

- With the vehicle in NEUTRAL, position it on a hoist.

- Inspect the suspect wheel speed sensor for looseness.

Is the wheel speed sensor loose?

Yes
TIGHTEN the wheel speed sensor to specification. REFER to Specifications. CLEAR the DTCs. GO to D4.

No
GO to D5.

D4 CHECK THE WHEEL SPEED PIDs

- Connect the scan tool.

- Enter the following diagnostic mode on the scan tool: DataLogger- ABS Module.

- Ignition ON.

- Monitor the following PIDs while driving the vehicle at a constant speed:
- Left Front Wheel Speed Sensor (LF_WSPD)

- Right Front Wheel Speed Sensor (RF_WSPD)

- Left Rear Wheel Speed Sensor (LR_WSPD)

- Right Rear Wheel Speed Sensor (RR_WSPD)


Are all the wheel speed sensor PID values similar?

Yes
The vehicle is OK. The concern may have been caused by a loose wheel speed sensor.

No
GO to D5.

D5 INSPECT THE WHEEL SPEED SENSOR FOR DAMAGE

- With the vehicle in NEUTRAL, position it on a hoist.

- NOTE: Examine the wheel speed sensor wire carefully with a good light source. Failure to verify damage in the wheel speed sensor wire can lead to unnecessary installation of a new component.
Inspect the suspect wheel speed sensor for cut/pinched wires, stressed wires at connectors, bent/corroded pins, etc.


Is the wheel speed sensor OK?

Yes
GO to D6.

No
INSTALL a new wheel speed sensor. REFER to Wheel Speed Sensor - Front or Wheel Speed Sensor - Rear . CLEAR the DTCs. REPEAT the self-test.

D6 INSPECT THE WHEEL SPEED SENSOR RING FOR DAMAGE

- Inspect the suspect wheel speed sensor ring for damaged or missing teeth. Rotate the wheel to verify that no teeth are missing.

Is the wheel speed sensor ring OK?

Yes
GO to D7.

No
INSTALL a new front or rear wheel speed sensor ring. For the front wheel speed sensor tone ring, REFER to Wheel Speed Sensor Ring - Front . For the rear wheel speed sensor tone ring, REFER to Wheel Speed Sensor Ring - Rear . CLEAR the DTCs. REPEAT the self-test.

D7 INSPECT THE WHEEL BEARING FOR DAMAGE

NOTE: The Active Wheel Speed Sensor Tester cannot be used for the rear wheel speed sensors on vehicles equipped with Active Park Assist.

- Inspect the wheel bearings for damage.

Are the wheel bearings OK?

Yes
If the Active Wheel Speed Sensor Tester is available, GO to D8.

If the Active Wheel Speed Sensor Tester is not available, GO to D10.

No
INSTALL a new wheel bearing and wheel hub as necessary. CLEAR the DTCs. REPEAT the self-test.

D8 CHECK THE ABS MODULE OUTPUT USING THE ACTIVE WHEEL SPEED SENSOR TESTER

NOTE: The Active Wheel Speed Sensor Tester cannot be used on vehicles equipped with active park assist.

- Ignition OFF.

- Disconnect: Suspect Wheel Speed Sensor.

- Connect the Active Wheel Speed Sensor Tester to the wheel speed sensor connectors.

- Ignition ON.

- Select the correct system polarity on the Active Wheel Speed Sensor Tester and turn the Active Wheel Speed Sensor Tester power switch to the ON position.

Is the module output LED illuminated?

Yes
GO to D9.

No
GO to D11.

D9 CHECK THE WHEEL SPEED SENSOR OUTPUT WITH THE ACTIVE WHEEL SPEED SENSOR TESTER

- Raise the suspect wheel until it can spin freely.

- While monitoring the Active Wheel Speed Sensor Tester, slowly spin the suspect wheel.

Do the sensor output LEDs illuminate and flash and is the current overload LED not illuminated?

Yes
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.

No
If the current level LED is not illuminated and the sensor output LEDs do not illuminate or if the current level LED is illuminated red, INSTALL a new wheel speed sensor. For the front wheel speed sensor, REFER to Wheel Speed Sensor - Front . For the rear wheel speed sensor, REFER to Wheel Speed Sensor - Rear . CLEAR the DTCs. REPEAT the self-test.

If the current level LED is not illuminated and the sensor output LEDs illuminate green but do not flash, INSPECT the wheel speed sensor tone ring and INSTALL new if necessary. For the front wheel speed sensor tone ring, REFER to Wheel Speed Sensor Ring - Front . For the rear wheel speed sensor tone ring, REFER to Wheel Speed Sensor Ring - Rear . If the tone ring is OK, INSTALL a new wheel speed sensor. For the front wheel speed sensor, REFER to Wheel Speed Sensor - Front . For the rear wheel speed sensor, REFER to Wheel Speed Sensor - Rear . CLEAR the DTCs. REPEAT the self-test.

D10 CHECK THE ABS MODULE OUTPUT

- Ignition OFF.

- Disconnect: Suspect Wheel Speed Sensor.

- Ignition ON.

- For DTC C1233, measure the voltage between LF wheel speed sensor C150-1, circuit RCA17 (YE), harness side and LF wheel speed sensor C150-2, circuit VCA03 (VT/WH), harness side.

- For DTC C1234, measure the voltage between RF wheel speed sensor C160-1, circuit RCA19 (VT), harness side and RF wheel speed sensor C160-2, circuit VCA05 (GY/VT), harness side.

- For DTC C1235, measure the voltage between RR wheel speed sensor C426-2, circuit RCA20 (BN), harness side and RR wheel speed sensor C426-1, circuit VCA06 (WH/OG), harness side.

- For DTC C1236, measure the voltage between LR wheel speed sensor C440-2, circuit RCA18 (BN/GN), harness side and LR wheel speed sensor C440-1, circuit VCA04 (BU/OG), harness side.





Are the voltages greater than 10 volts?

Yes
INSTALL a new wheel speed sensor. REFER to Wheel Speed Sensor - Front or Wheel Speed Sensor - Rear . CLEAR the DTCs. TEST DRIVE the vehicle. REPEAT the self-test.

No
GO to D11.

D11 CHECK THE WHEEL SPEED CIRCUITS FOR AN OPEN

NOTE: Both circuits must be checked for each DTC.

- For vehicles equipped with a 3.0L engine, with the vehicle in NEUTRAL, position it on a hoist.

- Ignition OFF.

- Disconnect: ABS Module C155.

- Disconnect: Suspect Wheel Speed Sensor (if not previously disconnected).

- Measure the resistance between the ABS module connector, harness side and the suspect wheel speed sensor connector, harness side as indicated in the following chart:

ABS Module Circuit Wheel Speed Sensor DTC C1234- Wheel Speed Sensor RF Input Circuit Failure C155-34 VCA05 (GY/VT) C160-2 C155-33 RCA19 (VT) C160-1 DTC C1233- Wheel Speed Sensor LF Input Circuit Failure C155-45 VCA03 (VT/WH) C150-2 C155-46 RCA17 (YE) C150-1 DTC C1235- Wheel Speed Sensor RR Input Circuit Failure C155-43 VCA06 (WH/OG) C426-1 C155-42 RCA20 (BN) C426-2 DTC C1236- Wheel Speed Sensor LR Input Circuit Failure C155-36 VCA04 (BU/OG) C440-1 C155-37 RCA18 (BN/GN) C440-2





Are the resistances less than 5 ohms?

Yes
GO to D12.

No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.

D12 CHECK FOR CORRECT ABS MODULE OPERATION

- Check ABS module C155 for:
- corrosion.
- pushed-out pins.
- spread terminals.


- Connect: ABS Module C155.

- Connect: Suspect Wheel Speed Sensor.

- Make sure the connector seats correctly. Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module . TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.

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