Pinpoint Test M: DTC C1991 - Module Calibration Failure

NOTE: The stability assist lamp flashes when a system calibration is required. Calibration is required after certain diagnostic trouble codes (DTCs) are cleared.

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

M1 CHECK FOR DTCs
- Connect the scan tool.
- Key in ON position.
- Retrieve the recorded results from the smart junction box (SJB) self-test.
- Is any other DTC retrieved with C1991?
Yes : GO to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .

Some of the pinpoint tests recommend ABS module calibration prior to any further diagnostics. In this case, GO to M2.

No : GO to M2.
M2 CALIBRATE THE ABS MODULE
- Key in START position.
- Carry out the ABS module calibration per the scan tool instructions.
- Does the calibration complete for all of the stability assist sensors, and does the stability assist lamp stop flashing and turn off?
Yes : GO to M3.

No : GO to M4.

Some concerns cause the calibration not to complete. If sent here from another pinpoint test, return to that pinpoint test for further diagnostics.
M3 CLEAR DTC C1991
NOTE: Clear DTC C1991 after completing the calibration.
- Connect the scan tool.
- Key in ON position.
- CLEAR the DTC.
- Does the DTC clear?
Yes : TEST DRIVE the vehicle. REPEAT the self-test.

If sent here from another pinpoint test, return to that pinpoint test for further diagnostics.

No : GO to M4.
M4 MONITOR THE STEERING WHEEL ROTATION SENSOR PIDs
- Key in ON position.
- Monitor the ABS module steering wheel rotation sensor PIDs while rotating the steering wheel clockwise and counterclockwise.
- Are the 2 steering wheel rotation sensor PID values switching as the wheel rotates?
Yes : GO to PINPOINT TEST H .

No : GO to PINPOINT TEST G .