C0208
DTC C0205-C0208
Test 1-6
Test 7-14
Circuit Description
The steering wheel position sensor produces 2 separate voltage signals to indicate steering wheel position to the Real Time Damping (RTD) module. The RTD module converts each signal into a Pulse Width Modulated (PWM) signal to indicate steering wheel position to the EBCM. The EBCM supplies 5 volts to the RTD module on each steering wheel position PWM serial data circuit. The RTD module toggles each of these voltages to ground in order to create the PWM signals. Each PWM signal must have a frequency of 121 - 134 Hz and a duty cycle of 91 percent in order to be a valid steering wheel position signal. With each 360 degree rotation of the steering wheel, each signal transitions from the minimum duty cycle to the maximum duty cycle and then back to the minimum duty cycle. The steering wheel position signals are spaced 90 degrees apart. Therefore, the duty cycles of the 2 signals usually differ, depending on steering wheel position.
Conditions for Running the DTC
C0205, C0206 and C0207
The ignition is ON.
C0208
The vehicle is driven straight forward at a speed greater than 19 km/h (12 mph) for more than 20 seconds.
Conditions for Setting the DTC
C0205
At least one of the steering wheel position PWM signals is out of range for 500 milliseconds.
C0206
The steering wheel position PWM signals indicate a sudden change in the steering wheel position which exceeds a physical limitation.
C0207
The steering wheel position PWM signals do not correlate with each other for 200 milliseconds.
C0208
The steering wheel position that is indicated while driving the vehicle straight forward is at least 20 degrees greater or less than the steering wheel position that was indicated during the sensor initialization period.
Action Taken When the DTC Sets
^ The EBCM disables the VSES.
^ The message center displays the SERVICE STABILITY SYSTEM message.
Conditions for Clearing the DTC
The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.
Diagnostic Aids
Important: A malfunction between the steering wheel position sensor and the RTD module may be responsible for setting this DTC. When attempting to verify an intermittent malfunction be sure to use the scan tool to send the clear DTCs command to the RTD module. This enhances the RTD module's diagnostic capabilities so that the RTD module sets DTCs more readily. Do not cycle the ignition after sending the Clear DTCs command. Test drive the vehicle, making several turning maneuvers in both directions. If the service stability message is displayed due to DTC C0205, C0206, C0207 or C0208, use the scan tool to inspect for Current or History RTD DTCs. If the RTD module has set DTC C0470, C0506, C0521 or C0895, refer to the DTC list in Variable Effort Steering for diagnosis. If the RTD module has set DTC C0550, C0551 or CO870, refer to the DTC list in Real Time Damping for diagnosis.
^ Inspect the vehicle for bent, worn or loose steering or suspension components.
^ Inspect the vehicle for proper wheel alignment. The vehicle should not pull toward the left or right while driving straight forward on a level surface.
^ Use the Snapshot function on the scan tool in order to assist you in locating an intermittent malfunction.
^ Thoroughly inspect connections or circuitry that may cause an intermittent malfunction.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. This step determines if there is a problem between the steering wheel position sensor and the RTD module.
5. This step tests for voltages supplied to the RTD module from the EBCM. A short to voltage is indicated if voltage on either circuit measures greater than 5.25 volts.
7. This step tests each steering wheel position PWM signal for a valid Hz frequency. Each measurement is made by backprobing one steering wheel position PWM signal circuit at the RTD module harness connector with one DMM lead and connecting the other DMM lead to a good ground.
8. This step tests each steering wheel position PWM signal for a valid duty cycle.
11. The RTD module may be damaged if either of the steering wheel position PWM serial data circuits is shorted to voltage.