Circuit Description
The electro-hydraulic power steering (EHPS) system uses the Phase A and Phase B signal inputs from the steering wheel sensor for proper operation. The steering wheel sensor outputs Phase A and Phase B signals to the EHPS system that are 90 degrees out of phase to provide quadrature pulsed data corresponding to steering shaft rotational displacement and direction. The signal is resolved to within 1 mechanical degree of resolution. The EHPS system monitors the steering wheel rate information from the steering wheel sensor every 5 milliseconds (200 Hz) for proper operation.
Conditions for Running the DTC
| • | EHPS module in RUN mode. |
| • | Ignition switch in ACC or ON position. |
| • | Battery voltage between 12-58 volts. |
Conditions for Setting the DTC
Steering wheel sensor rate information calculated from the sensor is greater than 2,200 degrees per second (sensor phase A jitter).
Action Taken When the DTC Sets
| • | System operation is reduced. |
| • | The SERVICE STEER SYSTEM message will be displayed. |
| • | Ramp the motor speed input to the commanded flow resolved from a default steering wheel rate. |
| • | Stores a DTC C0511 in the powertrain control module (PCM). |
| • | History DTC C0511 will be set in PCM. |
Conditions for Clearing the DTC
| • | Steering wheel rate information calculated from the sensor is greater than 2,200 degrees. |
| • | Using the scan tool. |
| • | A history DTC will clear after 255 consecutive ignition cycles if the condition for the malfunction is no longer present. |
Diagnostic Aids
Ignition cycling is not necessary for reallowing EHPS system to operate normally.
It may be necessary to check Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Test for the proper operation of phase A circuit.
-
Test for the proper operation of the phase B circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Power Steering Schematics Connector End Views Reference: Power Steering Connector End Views | ||||
1 | Did you perform the electo-hydraulic power steering (EHPS) Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Do the parameters display steering wheel phases alternate as indicated? | high/low | Go to Diagnostic Aids | Go to Step 3 |
With a scan tool, observe the Phase A parameter, while turning the steering wheel. Does the Phase A Data parameter change state? | high/low | Go to Step 4 | Go to Step 5 | |
4 | Does the scan tool indicate that the Phase A Data parameter is always high? | -- | Go to Step 8 | Go to Step 7 |
With a scan tool, observe the Phase B parameter, while turning the steering wheel. Does the Phase B Parameter change state? | high/low | Go to Step 13 | Go to Step 6 | |
6 | Does the scan tool indicate that the Phase B parameter is always high? | -- | Go to Step 8 | Go to Step 7 |
7 | Test the steering wheel position sensor phase A or phase B circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems? Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 |
8 | Test the steering wheel position sensor phase A or phase B circuit for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
9 | Inspect for poor connections at the harness connector of the steering wheel position sensor connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 |
10 | Inspect for poor connections at the harness connector of the EHPS module connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
11 |
Important: Perform the Learn Alignment procedure. Refer to Wheel Alignment Measurement in Wheel Alignment. Replace the steering wheel position sensor. Refer to Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement in Steering Wheel and Column. Did you complete the replacement? | -- | Go to Step 13 | -- |
12 |
Important: Always perform the calibration procedure for the brake pedal position (BPP) sensor. Refer to Brake Pedal Position Sensor Calibration Description and Operation . Replace the EHPS powerpack. Refer to Power Steering Pump Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
