Pinpoint Test I: DTC C1996
Anti-Lock Control
Pinpoint Tests
Pinpoint Test I: DTC C1996
Normal Operation
The ABS module uses information received from several sensors (wheel speed sensors, steering wheel rotation sensor, stability control sensor cluster) to determine if a vehicle instability event is about to occur. If an event is going to occur, the ABS module will adjust brake torque at specific wheels and the PCM will reduce engine torque to make the vehicle more stable. Once the ABS module has determined that the stability event has been corrected, it will return brake and engine torque to normal and continue to monitor the vehicle.
- DTC C1996 (Active Yaw and/or Roll Control Disabled) - The ABS module monitors the stability event and is programmed to set DTC C1996 and disable the stability control system if the stability event lasts longer than 15 seconds.
This pinpoint test is intended to diagnose the following:
- Steering wheel rotation sensor
- Stability control sensor cluster
- Wheel speed sensors
- ABS module
PINPOINT TEST I: DTC C1996
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I1 CHECK FOR ABS MODULE DTCs
- Review the DTCs recorded during Inspection and Verification.
- Are any DTCs other than C1996 present?
Yes
REPAIR all other DTCs before repairing C1996. GO to the ABS Module DTC Chart. ABS Module DTC Chart
No
GO to I2.
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I2 CHECK RETURNING DTCs
- Connect the scan tool.
- Ignition ON.
- Using the scan tool, clear all ABS module DTCs.
- Cycle the ignition switch from RUN to OFF and back to RUN.
- Test drive the vehicle above 49 km/h (30 mph).
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module.
- Are any ABS module DTCs present?
Yes
If only DTC C1996 is present, GO to I3.
If DTC C1996 is present along with other DTCs, REPAIR the other DTCs before repairing DTC C1996. GO to the ABS Module DTC Chart. ABS Module DTC Chart
No
The condition is not present at this time.
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I3 CHECK THE WHEEL SPEED SENSOR PIDs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - ABS.
- While driving the vehicle, have an assistant monitor the following wheel speed sensor PIDs:
- Left Front Wheel Speed (LF_WSPD)
- Right Front Wheel Speed (RF_WSPD)
- Left Rear Wheel Speed (LR_WSPD)
- Right Rear Wheel Speed (RR_WSPD)
- Do all the PIDs match the vehicle speed and match each other?
Yes
GO to I8.
No
GO to I4.
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I4 INSPECT THE WHEEL SPEED SENSOR MOUNTING
- With the vehicle in NEUTRAL, position it on a hoist. Refer to Jacking and Lifting Service and Repair.
- Ignition OFF.
- Verify the bolt of the suspect wheel speed sensor is tightened to specifications.
- Is the bolt tightened to specifications?
Yes
GO to I5.
No
TIGHTEN the wheel speed sensor bolt to specification. REFER to Specifications. CLEAR the DTCs.
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I5 INSPECT THE WHEEL SPEED SENSOR AND HARNESS FOR DAMAGE
- NOTE: Examine the wheel speed sensor harness carefully with a good light source. Failure to verify damage in the sensor harness can lead to unnecessary installation of a new component.
- Inspect the suspect wheel speed sensor and harness for cuts, broken tabs, broken casing and/or corrosion.
- Are the wheel speed sensor and harness OK?
Yes
GO to I6.
No
INSTALL a new wheel speed sensor. REFER to Wheel Speed Sensor - Front Wheel Speed Sensor - Front or Wheel Speed Sensor - Rear Wheel Speed Sensor - Rear. CLEAR the DTCs. REPEAT the self-test.
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I6 INSPECT THE WHEEL SPEED SENSOR RING FOR DAMAGE
- NOTE: Examine the wheel speed sensor ring carefully with a good light source. Failure to verify damage in the sensor ring can lead to unnecessary installation of a new component.
- Inspect the suspect wheel speed sensor ring for cracks, chips and other similar damage.
- Is the wheel speed sensor ring OK?
Yes
GO to I7.
No
INSTALL a new wheel hub and bearing assembly (wheel speed sensor rings are part of the wheel hub and bearing assembly). CLEAR the DTCs. REPEAT the self-test.
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I7 INSPECT THE WHEEL BEARING FOR DAMAGE AND LOOSENESS
- Verify that the wheel bearing has no end-play and is undamaged.
- Is the wheel bearing OK?
Yes
GO to I8.
No
INSTALL a new wheel hub and bearing assembly. CLEAR the DTCs. REPEAT the self-test.
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I8 CHECK THE ABS MODULE YAW RATE (YAWRATE) PID
- NOTE: The vehicle must be on level ground and at a complete standstill. Any vehicle movement results in false values for this test.
- Monitor the YAWRATE PID.
- Is the YAWRATE PID value between -0.004 and 0.004?
Yes
GO to I9.
No
GO to I10.
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I9 CHECK THE ABS MODULE LATERAL ACCELERATION (LAT_ACCL) PID
- NOTE: The vehicle must be on level ground and at a complete standstill. Any vehicle movement results in false values for this test.
- Monitor the LAT_ACCL PID.
- Is the LAT_ACCL PID value between -0.3 and 0.3?
Yes
GO to I11.
No
GO to I10.
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I10 CHECK THE SENSOR CLUSTER INSTALLATION AND MOUNTING SURFACE
- Inspect the sensor cluster installation and make sure that the nuts are fully seated and tightened correctly. Refer to Stability Control Sensor Cluster Service and Repair.
- Inspect the mounting surface for damage, corrosion or dirt.
- Was the sensor cluster installed incorrectly and is the mounting surface clean and free from damage?
Yes
GO to I11.
No
REPAIR or INSTALL new as necessary. CLEAR the DTC. REPEAT the self-test.
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I11 CHECK THE STEERING WHEEL ANGLE SENSOR POSITION (SWA POS) PID
- Monitor the SWA POS PID while rotating the steering wheel clockwise and counterclockwise very slowly, from lock to lock.
- Does the PID change in intervals of 1.5 degrees and show a 360-degree increase for each complete revolution of the steering wheel?
Yes
GO to I12.
No
GO to Pinpoint Test F. Pinpoint Test F: DTCs C1277, C1278 and C1963
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I12 CHECK FOR CORRECT ABS MODULE OPERATION
- Disconnect: ABS Module C155.
- Check the connector for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: ABS Module C155.
- Make sure the ABS module electrical connector is fully seated, then 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 Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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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