For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category

### DTC Descriptor

DTC C0252 00: Implausible Control

### Circuit/System Description

The ESP is activated by the electronic brake control module (EBCM) calculating the desired yaw rate and comparing it to the actual yaw rate input. The desired yaw rate is calculated from measured steering wheel position, vehicle speed, and lateral acceleration. The difference between the desired yaw rate and actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. If the yaw rate error becomes too large, the EBCM will attempt to correct the vehicles yaw motion by applying differential braking to the wheels. The amount of differential braking applied to the left or right front wheel is based on both the yaw rate error and side slip rate error. The side slip rate error is a function of the lateral acceleration minus the product of the yaw rate and vehicle speed.

### Conditions for Running the DTC

• | The ignition is ON.

• | Ignition voltage is greater than 8 volts.

### Conditions for Setting the DTC

• | A yaw rate sensor fault occurs with the vehicle speed between 22 km/h (13.6 mph) and 100 km/h (62.1 mph).

• | The steering angle sensor fault occurs within a 10 second period while the vehicle is driven below 100 km/h (62.1 mph).

• | The steering angle sensor fault occurs within a 5 second period while the vehicle is driven above 100 km/h (62.1 mph).

• | All four ABS solenoids are continuously maintaining/releasing pressure during ABS control within a 1.28 second period.

### Action Taken When the DTC Sets

• | The EBCM disables the Antilock Brake System (ABS)/Traction Control System (TCS)/Electronic Stability Control (ESP)/Electronic Brake Distribution (EBD) for the duration of the ignition cycle.

• | The multi function display (MFD) displays the ABS Fault message.

• | The multi function display (MFD) displays the Traction Ctrl Off message.

• | The multi function display (MFD) displays the Stability Ctrl Off message.

### Conditions for Clearing the DTC

• | The condition for setting the DTC is no longer present.

• | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

• | The DTC can be cleared using a scan tool.

### Diagnostic Aids

• | This DTC will set if there is a mismatch between the data supplied by the sensors to the EBCM.

• | This DTC will set when there is a sensor is installed incorrectly or is the incorrect type.

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Testing

1. Using the scan tool verify that no other steering angle sensor or yaw rate sensor DTCs are set as current.

⇒ | If any other DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

2. Calibrate/program the EBCM.
3. Ignition ON, using a scan tool view the current DTCs.

⇒ | If DTC C0252 is set to current, inspect steering angle/yaw rate sensor mounting and version number to confirm correct installation and type.

### Repair Instructions

• | Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Steering Angle Sensor Replacement

• | Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement

• | Control Module References