DTC C1281 Active Handling Sensors Uncorrelated RPO JL4
Circuit Description
Active Handling™ is activated by calculating the driver's desired yaw rate (based on wheel speed sensor inputs, lateral acceleration and steering wheel position information) and compares it to the actual yaw rate as measured by the yaw rate sensor. The difference between these two is the yaw rate error, which is then used to determine the amount of oversteer or understeer. If the yaw rate error becomes too large the system attempts to correct the vehicle's yaw motion by using differential braking on the left or right front and rear wheel brakes. To correct for oversteer differential braking is used on the left or right rear wheel brakes. To correct for understeer differential braking is used on the left or right front wheel brakes.
Conditions for Setting the DTC
| • | The analog and digital steering sensor do not agree for one second while in an Active Handling™ event. |
| • | DTC C1281 can be set any time after the steering angle has been centered and Active Handling™ is activated. If the Active Handling event occurs for 10 seconds without a sign of the yaw rate error ever changing this code will be set. This is the only condition that will set DTC C1281 by itself. |
| • | DTC C1281 can be set along with DTC C1287. During an Active Handling event the EBTCM does a comparison between the SWPS digital value and the SWPS analog value. If the difference is greater than 20 degrees for 1 second both DTC C1281 and DTC C1287 will be set. |
| • | DTC C1281 can be set along with DTC C1282. During an Active Handling event the EBTCM does a comparison between the actual yaw rate and a yaw rate derived from the difference in output from the front wheel speed sensors during an understeer condition or the rear wheel speed sensors during an oversteer condition. If this yaw rate difference is greater than 10 degrees/seconds for more than 5 seconds DTC C1281 and DTC C1282 will be set. The use of DTC C1281 with DTC C1282 indicates that the road surface (typically ice) may have created an unusually long period where the wheel speed estimate of yaw rate may have been inaccurate due to vehicle sideslip. This means the DTCs may have been falsely set. |
| • | Normal conditions which could cause code C1281 to set include Active Handling™ activation's brought on by aggressive driving on extremely slippery road surfaces for example, spinning the car in one direction for greater than 10 seconds. This means the DTC may have been falsely set due to aggressive driving. |
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 |
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 and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | 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. |
| • | The Snapshot function on the scan tool may help in finding an intermittent DTC C1281. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
This step checks the accuracy of the analog and digital inputs from the SWPS.
-
This step checks for inaccurate yaw rate sensor input.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to A Diagnostic System Check - ABS | |
2 | Is this vehicle equipped with Active Handling (RPO JL4)? | -- | ||
3 |
Are any of the following DTC(s) present, C1221-C1235, C1282 or C1287? | -- | Go to Applicable DTC table. Refer to Diagnostic Trouble Code (DTC) List | |
Using the scan tool perform the Steering Wheel Position Sensor Test. Refer to Scan Tool Diagnostics . Is the analog and digital display on the scan tool within plus or minus 5 degrees of each other at the center (zero) position? | -- | |||
5 | Replace the Steering Wheel Position Sensor. Refer to Steering Shaft, Lower Bearing, and Jacket - Disassemble - Off Vehicle (Telescoping Column) in Steering Wheel and Column - Tilt. Is the replacement complete? | -- | -- | |
Carefully drive vehicle above 24 Km/h (15 mph) for 45 seconds in a straight line, while monitoring the Yaw Rate sensor with a scan tool. Is 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 | Perform the Diagnostic Test Drive. Refer to Diagnostic Test Drive . Did DTC C1281 set as a current DTC? | -- | Go to A Diagnostic System Check - ABS | |
9 | Replace the EBTCM Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | Go to A Diagnostic System Check - ABS | -- |
