Pinpoint Test F: DTCs C1222 And C1237
Anti-Lock Control
Pinpoint Tests
Pinpoint Test F: DTCs C1222 and C1237
Refer to Wiring Diagram Set 42, Dynamic Systems for schematic and connector information. Diagrams By Number
Normal Operation
The front wheel speed sensors are "active" sensors and generate a square wave signal that is sent to the ABS module. When the ignition is turned to the RUN position, the ABS module carries out a self-test to determine if the sensors are functional. Voltage and ground are supplied to the front wheel speed sensors from the ABS module along a pair of wires.
The rear wheel speed information is sent to the ABS module from the PCM over the High Speed Controller Area Network (HS-CAN) bus. The PCM receives the information from the transmission Output Shaft Speed (OSS) sensor.
Wheel speed sensor DTCs will automatically clear when a successful test drive is carried out. A successful test drive should include speeds above 32 km/h (20 mph) for at least 3 minutes and at least one ABS stop.
- DTC C1222 (Wheel Speed Mismatch) - When the vehicle speed exceeds 20 km/h (12 mph), if the ABS module detects a difference between wheel speed sensor signals, DTC C1222 will be set. DTC C1222 can also be set by damaged tone rings, mismatched wheel and/or tire sizes, driving the vehicle on one or more underinflated tires, an incorrect axle ratio in the PCM or the wrong axle being installed on the vehicle.
- DTC C1237 (Rear Wheel Speed Input Signal Missing) - When the vehicle speed exceeds 20 km/h (12 mph), if the ABS module does not receive the rear wheel speed sensor information from the PCM, DTC C1237 will be set.
This pinpoint test is intended to diagnose the following:
- Mismatched tire sizes
- Wheel speed sensor ring
- Wheel speed sensor
- OSS sensor
- OSS sensor tone ring
- Incorrect PCM configuration
- Incorrect rear axle
- HS-CAN bus
- ABS module
PINPOINT TEST F: DTCs C1222 AND C1237
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
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F1 CHECK THE ABS MODULE DTCs
- Review the DTCs retrieved during Inspection and Verification.
- Is DTC C1237 the only DTC present?
Yes
REFER to Transmission Control Systems to diagnose the transmission OSS sensor. Testing and Inspection
No
If DTCs U0115 and/or U0073 are also present, REFER to Information Bus to diagnose the HS-CAN bus before diagnosing C1237 or C1222.
If only C1222 is present or if both DTCs C1222 and C1237 are present without DTC U0115 or U0073, GO to F2.
For all other ABS module DTCs, REFER to the ABS Module DTC Chart. ABS Module DTC Chart
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F2 CHECK THE ABS HARNESS AND MODULE FOR WATER INTRUSION
- Ignition OFF.
- Disconnect: ABS Module C135.
- Inspect the ABS module connector and module for water intrusion.
- Is there any evidence of water entry?
Yes
CLEAN the connector and dry it out with low-pressure compressed air. INSPECT for evidence of water entry and repair as necessary. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
No
GO to F3.
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F3 CHECK FOR CORRECT TIRE SIZE AND AIR PRESSURE
- Verify that the tires are the correct size for the vehicle as indicated on the Vehicle Certification (VC) label.
- Verify that the air pressure in all the tires is correct as indicated on the VC label.
- Are the tire sizes and air pressure OK?
Yes
GO to F4.
No
ADJUST the tire pressure or INSTALL a new tire(s) as necessary. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
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F4 MONITOR THE WHEEL SPEED SENSOR PIDs
- Connect: ABS Module C135.
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - ABS Module.
- While driving the vehicle at a constant speed, have an assistant monitor the following wheel speed sensor PIDs:
- Left Front Wheel Speed Sensor (LF_WSPD)
- Right Front Wheel Speed Sensor (RF_WSPD)
- Rear Differential Wheel Speed (R_DIF_SPD)
- Do all 3 PID values match each other?
Yes
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
No
If both front PIDs match each other but do not match the rear PID, GO to F5.
If the front PIDs do not match each other but one front PID matches the rear PID, GO to F7.
If none of the PIDs match each other, GO to F7.
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F5 CHECK THE PCM AXLE RATIO (AXLE) PID
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Read and record the AXLE PID value.
- Does the PID value match the axle that is installed on the vehicle?
Yes
GO to F6.
No
RECONFIGURE the PCM. REFER to Programmable Module Installation (PMI) in Information Bus. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop. Programming and Relearning
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F6 CHECK FOR RETURNING ABS MODULE DTCs
- Clear all ABS module DTCs.
- Test drive the vehicle at speeds above 32 km/h (20 mph) and carry out at least one ABS stop.
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module.
- Read and record the ABS module DTCs
- Are DTCs U0115 and/or U0073 present?
Yes
REFER to Information Bus to diagnose the HS-CAN bus.
No
REFER to Transmission Control Systems to diagnose the transmission OSS sensor. Testing and Inspection
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F7 CHECK THE WHEEL SPEED SENSOR FOR DAMAGE AND/OR LOOSENESS
- Ignition OFF.
- With the vehicle in NEUTRAL, position it on a hoist. Refer to Maintenance/Service and Repair.
- NOTE: Examine the wheel speed sensor wire carefully with a good light. Failure to verify damage in the wheel speed sensor wire can lead to unnecessary installation of a new component.
- Inspect the wheel speed sensor mounting for looseness. Check for corrosion on the wheel speed sensor mounting flange. Clean as necessary.
- Is the wheel speed sensor OK?
Yes
GO to F8.
No
INSTALL a new wheel speed sensor. REFER to Wheel Speed Sensor - Front Wheel Speed Sensor - Front. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
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F8 CHECK FOR WHEEL SPEED SENSOR RING DAMAGE
- Remove the wheel speed sensor.
- Inspect the wheel speed sensor rings for damaged or missing teeth.
- Is the wheel speed sensor ring OK?
Yes
If the Active Wheel Speed Sensor Tester is available, GO to F9.
If the Active Wheel Speed Sensor Tester is not available, GO to F11.
No
INSTALL a new wheel speed sensor ring. REFER to Wheel Speed Sensor - Front Wheel Speed Sensor - Front. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
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F9 CHECK THE ABS MODULE OUTPUT USING THE ACTIVE WHEEL SPEED SENSOR TESTER
- 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 power switch to the ON position.
- Is the module output LED illuminated?
Yes
GO to F10.
No
GO to F11.
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F10 CHECK THE WHEEL SPEED SENSOR OUTPUT WITH THE ACTIVE WHEEL SPEED SENSOR TESTER
- Raise the suspect wheel until it can spin freely. Refer to Maintenance/Service and Repair.
- While monitoring the Active Wheel Speed Sensor Tester, slowly spin the suspect wheel.
- Is the current level LED illuminated green and do the sensor output LEDs illuminate and flash?
Yes
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
No
If the current level LED is illuminated green and the sensor output LEDs do not illuminate or if the current level LED is illuminated red, INSTALL a new wheel speed sensor. REFER to Wheel Speed Sensor - Front Wheel Speed Sensor - Front. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
If the current level LED is illuminated green and the sensor output LEDs illuminate green but do not flash, INSPECT the wheel speed sensor tone ring and INSTALL new if necessary. REFER to Wheel Speed Sensor Ring - Front Wheel Speed Sensor Ring - Front. If the tone ring is OK, INSTALL a new wheel speed sensor. REFER to Wheel Speed Sensor - Front Wheel Speed Sensor - Front. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
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F11 CHECK THE ABS MODULE OUTPUT
- Disconnect: Suspect Wheel Speed Sensor.
- Ignition ON.
- Measure the voltage between RF wheel speed sensor C160-1, circuit VCA05 (GY/VT), harness side and RF wheel speed sensor C160-2, circuit RCA19 (VT), harness side.
- Measure the voltage between LF wheel speed sensor C150-1, circuit VCA03 (VT/WH), harness side and LF wheel speed sensor C150-2, circuit RCA17 (YE), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new wheel speed sensor. REFER to Wheel Speed Sensor - Front Wheel Speed Sensor - Front. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
No
GO to F12.
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F12 CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR AN OPEN
NOTE: Both circuits must be checked for each DTC.
- Ignition OFF.
- Disconnect: ABS Module C135.
- 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:
- Are the resistances less than 5 ohms?
Yes
GO to F13.
No
REPAIR the affected circuit(s). TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
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F13 CHECK FOR CORRECT ABS MODULE OPERATION
- Check ABS module C135 for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: ABS C135.
- Make sure the ABS connector seats correctly.
- Test drive the vehicle above 32 km/h (20 mph), carry out at least one ABS stop 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 Service and Repair. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop.
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