Pinpoint Test I: DTC C1991
Anti-Lock Control
Pinpoint Tests
Pinpoint Test I: DTC C1991
Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number
Normal Operation
The ABS module must be calibrated whenever a component specific to the Electronic Stability Control (ESC) or Roll Stability Control (RSC(R)) system is disconnected or a new component is installed.
- DTC C1991 (Module Calibration Failure) - If the IVD Initialization sequence 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
NOTE: The stability/traction control indicator "sliding-car icon" flashes once every 2 seconds 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.
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I1 CHECK FOR DTCs
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module.
- Retrieve and record any ABS module DTCs.
- Are other DTCs retrieved along with C1991?
Yes
GO to the ABS DTC Chart. ABS Module DTC Chart
Some of the pinpoint tests recommend ABS module calibration prior to any further diagnostics. In this case, GO to I2.
No
GO to I2.
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I2 CALIBRATE THE ABS MODULE
- Enter the following diagnostic mode on the scan tool: IVD Initialization Sequence.
- Carry out the IVD Initialization sequence. Follow the instruction on the scan tool.
- Does IVD Initialization sequence complete and the stability/traction control indicator stop flashing and turn off?
Yes
GO to I3.
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.
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I3 CLEAR DTC C1991
- Enter the following diagnostic mode on the scan tool: Clear All CMDTCs.
- Using the scan tool, clear the DTC.
- Does the DTC clear?
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.
No
GO to I4.
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I4 MONITOR THE ABS MODULE SASM (SWA POS) PID
- Ignition ON.
- Enter the following diagnostic mode on the scan 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?
Yes
GO to Pinpoint Test F. Pinpoint Test F: DTCs C1279, C1280, C1281, C1282, C1516, C1517, C2769 And C2770
No
GO to Pinpoint Test E. Pinpoint Test E: DTCs C1278 And C1963
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