Freestar V6-4.2L VIN 2 (2004)
Yaw Rate Sensor: Technical Service Bulletins
ABS - Module Replacement Service Tip
TSB 04-12-5
6/01/04
DIAGNOSTIC TROUBLE CODE (DTC) C1991 (MODULE
CALIBRATION FAILURE) - ANTI-LOCK BRAKE,
ADVANCED TRAC, INTERACTIVE VEHICLE
DYNAMICS (IVD), TRACTION CONTROL SYSTEM -
SERVICE TIP
FORD: 2004-2005 Freestar
MERCURY: 2004-2005 Monterey
ISSUE
When replacing the ABS module a code C1991 will be set. This is due to the new module not being calibrated. Proper calibration procedures must be
followed to successfully clear the C1991. The new ECU will not complete a successful module calibration if other codes are present, and will keep
resetting code C1991. DTC C1991 will be set if:
^
Other anti-lock brake system, traction control/IVD related codes are present during the calibration process.
^
Calibration setup criteria are not met.
^
Module is not calibrated.
ACTION
All other ABS related system conditions and/or DTC's must be resolved before module replacement and module calibration. If the vehicle exhibited a
condition and trouble code related to pressure transducer, YAW sensor, brake booster, or steering angle sensor, perform appropriate pinpoint tests and
diagnostics. Repair any wiring, connector, and/or sensor issues before module replacement. After the booster, SWA, YAW/LAT, or ECU has been
replaced, the ECU will need to be calibrated. Refer to the following Service Procedure.
SERVICE PROCEDURE
Freestar/Monterey module calibration can be performed using the NGS or WDS scan tools.
MODULE CALIBRATION USING WDS
With the brake pedal released, select the following:
1.
Toolbox.
2.
Chassis.
3.
Braking.
MERCURY:
2004-2005 Monterey
4.
IVD Initialization Sequence.
5.
Ensure that requirements on screen are met for the input you are about to calibrate, then press Confirm.
6.
Select YAW Rate/Lateral Acceleration Calibration and follow on-screen prompts.
YAW Sensor Calibration requirements
^
Vehicle in park.
^
Key on.
