Pinpoint Test I: DTC C1991 - Module Calibration Failure

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Vehicle Dynamic Systems for schematic and connector information.

Normal Operation

The ABS module must be calibrated whenever a component specific to the roll stability control (RSC) system is disconnected or a new component is installed.

DTC C1991 Module Calibration Failure - If the calibration procedure does not finish or if the ABS module looses the calibration information, DTC C1991 will be set.

This pinpoint test is intended to diagnose the following:

ABS module
Stability control sensor cluster
Steering angle sensor module (SASM)

PINPOINT TEST I: DTC C1991 - MODULE CALIBRATION FAILURE

NOTE: The RSC indicator flashes when a system calibration is required. Calibration is required after certain DTCs are cleared.

NOTE: Make sure the vehicle is not on a hoist and is sitting on level ground before carrying out ABS module calibration.

I1 CHECK FOR DTCs
- Connect the diagnostic tool.
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Self-Test ABS Module
- Retrieve and record any ABS module DTCs.
- Are other DTCs retrieved along with C1991?
1. YES : Go to the ABS MODULE DTC CHART .
  Some of the pinpoint tests recommend ABS module calibration prior to any further diagnostics. In this case, go to I2.
2. NO : Go to I2.
I2 CALIBRATE THE ABS MODULE
- Enter the following diagnostic mode on the diagnostic tool: ABS Module Calibration
- Carry out the ABS module calibration per the scan tool instructions.
- Does the calibration complete for all of the RSC sensors, and does the RSC indicator stop flashing and turn off?
1. YES : Go to I3.
2. NO : Go to I4.
  Some concerns cause the calibration not to complete. If sent here from another pinpoint test, return to that pinpoint test for further diagnostics.
I3 CLEAR DTC C1991
- Enter the following diagnostic mode on the diagnostic tool: Clear ABS Module DTCs
- Using the scan tool, clear the DTC.
- Does the DTC clear?
1. YES : TEST DRIVE the vehicle above 32 km/h (20 mph) and CARRY OUT at least one ABS stop. REPEAT the self-test.
  If sent here from another pinpoint test, return to that pinpoint test for further diagnostics.
2. NO : Go to I4.
I4 MONITOR THE ABS MODULE SASM (SWA POS) PID
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic 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?
1. YES : Go to Pinpoint Test F .
2. NO : Go to Pinpoint Test E .