DTC C1286 Steering/Lateral Accelerometer Sensor Bias Malfunction DTC C1286 (RPO JL4)
Circuit Description
Steer angle centering is the process by which the EBTCM calibrates the steering sensor output so that it reads zero when the steering wheel is centered. The initial steering wheel center position is calculated after driving 10 Km/h (6 mph) for more than 10 seconds in a straight line on a fairly level surface. The EBTCM uses the Yaw Rate Sensor, Lateral Accelerometer and Wheel Speed Sensors to tell if the vehicle is moving in a straight line. This centering routine is necessary to compensate for wear in the steering and suspension. Wear in the steering and suspension can result in a change in the relationship between the steering wheel and the front wheels. By running the centering routine the EBTCM can compensate for these changes by changing the digital and analog center position.
Conditions for Setting the DTC
| • | DTC C1286 can be set after the centering routines completion if the bias value is plus or minus 40 degrees from the previous bias value. |
| • | DTC C1286 can also be set at start up if the bias value was out of range on the last ignition cycle. |
Action Taken When the DTC Sets
ABS and TCS remain enabled, Active Handling™ is disabled.
| • | Indicators that turn on: |
| Car Icon (TCS indicator |
| • | Messages displayed on the DIC: |
| Service Active HNDLG |
| Service Vehicle Soon |
Conditions for Clearing the DTC
| • | Condition for DTC is no longer present and scan tool clear DTC function is used. |
| • | Fifty ignition cycles have passed with no DTCs detected. |
Diagnostic Aids
| • | It is very important to check the vehicle for proper alignment. The car should not pull in either direction while driving straight on a flat surface. |
| • | It is very important to find out from the driver when the code was set, (when the SERVICE ACTIVE HNDLG message was activated). This information may help to duplicate the failure. |
| • | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. Check connector C102 RH side rear of engine compart for water intrusion or missing plugs, and that the connector is oriented horizontal to prevent water intrusion. |
| • | An intermittent malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. Refer to Testing for Electrical Intermittents in Wiring Systems. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | ||
2 | Is this vehicle equipped with Active Handling (RPO JL4)? | -- | ||
3 | Using a scan tool, read ABS/TCS/Active handling DTC(s). Is DTC C1282 or DTC C1284 set as a current DTC? | -- | Go to Applicable DTC Table. Refer to Diagnostic Trouble Code (DTC) List | |
4 |
Is the voltage within the range specified within the value(s) column? | 2-3 V | ||
5 | Using a scan tool, perform the Steering Wheel Position Sensor Test. Refer to Scan Tool Diagnostics . Are the analog and digital displays on the scan tool within plus or minus 5 degrees of each other at the center (zero) position? | -- | ||
6 | Perform the Diagnostic Test Drive while monitoring the Yaw Rate Sensor output in degrees/seconds on a scan tool. Refer to Diagnostic System Check - ABS . Are the degrees/second displayed on the scan tool within the range specified in the value(s) column? | 0-5 degrees/second | ||
7 | Replace the Yaw Rate Sensor. Refer to Vehicle Yaw Sensor Replacement . Is the replacement complete? | -- | -- | |
8 | With the ignition switch in the ON position and the engine off, monitor the Lateral Accelerometer output in voltage using a scan tool. Is the voltage displayed on the scan tool within the range specified in the value(s) column? | 2.3-2.7V | ||
9 | Replace the Lateral Accelerometer. Refer to Lateral Accelerometer Replacement Is the replacement complete? | -- | -- | |
10 | Replace the EBTCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | -- | |
Does the analog voltage move to or close to 2.5 volts? | -- | |||
12 | Replace the Steering Wheel Position Sensor. Refer to Steering Shaft, Lower Bearing, and Jacket - Disassemble - Off Vehicle in Steering Wheel and Column. Is the replacement complete? | -- | -- | |
13 |
Is the repair complete? | -- | -- | |
14 |
Did DTC C1286 set as a current DTC? | -- |
