I recently had a new ac compressor and harmonic balancer installed. Since this was done, I am getting several messages on the DIC. After driving for about a minute the message comes up that active handling is warming up and the light comes on, about 5 minutes later 2 more messages come up, service active handling and service vehicle. The only code I am getting is 28 TCS C1283H. I do not think the alignment is off and the steering hasn't been messed with. I wasn't getting these messages until repair work was done. I have checked and cleaned the 2 ground connections on either side of the engine, and checked the connections in the area where work was done. I am not sure if the mechanic used any type cleaner on the engine after the ac compressor was replaced and possibly shorting out the EBCM. I am not sure what to do next. I don't want to get a new EBCM if it could be something else. I also read to check the yaw sensor, but I think the center console has to be removed to check this. Any help would be appreciated.

 

Have you read the diagnostic procedure yet?
DTC C1283 Excessive Time to Center Steering
Circuit Description
Steer angle centering is the process by which the EBCM 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 EBCM 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 EBCM can compensate for these changes by changing the digital and analog center position.
Conditions for Setting the DTC
The initial steering wheel center position will be determined quickly unless there is a large offset in the yaw sensor or lateral accelerometer output. When this happens the system will believe the steering is far off center even though the vehicle is being driven in a straight line. Under this condition and with a continuous vehicle speed of 40 km/h (25 mph) or greater for longer than 10 minutes, DTC C1283 will be set.
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 and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. Check connector C102 RH side rear of engine compartment 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.
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The Snapshot function on the scan tool may help in finding an intermittent DTC C1283.

Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
3. This step checks for the proper Lateral Accelerometer input.
5. This step checks for the proper Yaw Rate Sensor input.

 

IF,,,, they changed your damper,,,, they had the steering rack disconnected and removed. Thats the only way to replace the damper.. Take that up with the repair facility repair the SWPS. Right now it NOT zeroed when the steering wheel is straight ahead. Trust me on this one. Some one moved the steering wheel while it was disconnected.

DTC C1281, C1283, or C1286
Circuit Description
The vehicle stability enhancement system (VSES) is activated by the electronic brake control mdoule (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 vehicle's yaw motion by applying differential braking to the left or right front wheel.

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. The yaw rate error and side slip rate error are combined to produce the total delta velocity error. When the delta velocity error becomes too large and the VSES system activates, the drivers steering inputs combined with the differential braking will attempt to bring the delta velocity error toward zero.

The VSES activations generally occur during aggressive driving, in the turns or bumpy roads without much use of the accelerator pedal. When braking during VSES activation, the brake pedal will feel different than the ABS pedal pulsation. The brake pedal pulsates at a higher frequency during VSES activation.

Conditions for Running the DTC
C1281
The steer angle has been centered.
The VSES is active.
The direction (understeer or oversteer) of the delta velocity error has not changed.
The centered lateral acceleration value is less than 0.5 g.
The yaw rate error is less than 6 degrees/second.
The side slip error is greater than 1.8 meters/second*second.
C1283
The vehicle speed is greater than 40 km/h (25 mph).

C1286
The steer angle has been centered.

Conditions for Setting the DTC
C1281
One of the following conditions exists:

The VSES is engaged for 10 seconds with the delta velocity error always in either understeer or oversteer. Under this condition, this DTC will set by itself.
The yaw rate error is greater than 10 degrees/second for 5 seconds. Under this condition, this DTC will set along with DTC C1282.
The yaw rate error is greater than 10 degrees/second with the vehicle speed less than 60 km/h (37 mph) and the acceleration pedal is pressed more than 25 percent of the pedal travel range for 1 second during the VSES activation. Under this condition, this DTC will set along with DTC C1282.
With the yaw rate less than 8 degrees/second, the side slip error is greater than 4.9 meters/second*second for 5 seconds. Under this condition, this DTC will set along with DTC C1284.
With the vehicle speed greater than 10 km/h (6.2 mph) and less than 100 km/h (62 mph) and the centered yaw rate has a value that is positive and is greater than 10 degrees/second, the oversteer term is negative for 2 seconds. The oversteer term is the yaw rate value times the lateral acceleration value. Under this condition, this DTC will set along with DTC C1284.
With the steer rate less than 80 degrees/second, the difference between the 2 steering sensor signals (Phase A and Phase B) is greater than 20 degrees for 1 second. Under this condition, this DTC will set along with DTC C1287.
C1283
The vehicle has driven for 10 minutes without completing steer angle centering.

C1286
The steering sensor bias moves greater than 40 degrees after steer centering was accomplished.

Action Taken When the DTC Sets
The EBCM disables the VSES for the duration of the ignition cycle.
The Traction Control and Active Handling indicator turns ON.
The DIC displays the Service Active Handling message.
The ABS remains functional.
Conditions for Clearing the DTC
The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
The scan tool may display 2 additional characters after the DTC. Take note of the 2 character code and any other DTCs that are set. The 2 character code is an engineering aid used in order to determine the specific criteria which caused the DTC to set.
During diagnosis, park the vehicle on a level surface.
Check the vehicle for proper alignment. The car should not pull in either direction while driving straight on a level surface.
Find out from the driver under what conditions the DTC was set (when the DIC displayed the Service Active Handling message). This information will help to duplicate the failure.
The Snapshot function on the scan tool can help find an intermittent DTC.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

Perform the Steering Position Sensor Test in order to verify that the steering wheel position sensor (SWPS) is operating properly.

Verify that the lateral accelerometer input parameter is within the valid range.

Verify that the yaw rate input parameter is within the valid range.

Step
Action
Values
Yes
No

Schematic Reference: ABS Schematics

Connector End View Reference: ABS Connector End Views or Powertrain Control Module (PCM) Connector End Views

1
Did you perform the ABS Diagnostic System Check?
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Go to Step 2
Go to Diagnostic System Check - ABS

2
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With the scan tool, perform the Steering Position Sensor Test.
Did the SWPS pass the test?
--
Go to Step 3
Go to Step 7

3
With a scan tool, observe the Lateral Accelerometer Input parameter in the VSES data list.

Does the scan tool display within the specified range?
2.3-2.7 V
Go to Step 4
Go to Step 8

4
With a scan tool, observe the Yaw Rate Sensor Input parameter in the VSES data list.

Does the scan tool display within the specified range?
2.3-2.7 V
Go to Step 5
Go to Step 9

5
Use the scan tool in order to clear the DTCs.
Perform the Diagnostic Test Drive. Refer to Diagnostic Test Drive .
Does the DTC reset?
--
Go to Step 6
Go to Diagnostic Aids

6
Replace the EBCM. Refer to Electronic Brake Control Module (EBCM) Replacement .

Did you complete the repair?
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Go to Step 10
--

7
Replace the steering wheel position sensor (SWPS). Refer to Steering Shaft, Lower Bearing, and Jacket - Disassemble - Off Vehicle and Steering Shaft, Lower Bearing, and Jacket - Assemble - Off Vehicle in Steering Wheel and Column - Tilt.

Did you complete the replacement?
--
Go to Step 10
--

8
Replace the lateral accelerometer sensor. Refer to Lateral Accelerometer Replacement .

Did you complete the replacement?
--
Go to Step 10
--

9
Replace the yaw rate sensor. Refer to Yaw Rate Sensor Replacement .

Did you complete the replacement?
--
Go to Step 10
--

10
Use the scan tool in order to clear the DTCs.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?
--
Go to Step 2
System OK



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Document ID# 670697
2001 Chevrolet/Geo Corvette


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