Circuit Description
The electro-hydraulic power steering (EHPS) operates when voltage at the EHPS connector is in the range of 34-50 volts. The EHPS will go into standby mode if the supply voltage at the EHPS connector drops below 18 volts for more than 10 milliseconds. The EHPS module shall be turned back on once the supply voltage rises above 22 volts, without a key cycle being required. If the supply voltage drops below 12 volts, the EHPS module drivers shall shut down and a key cycle will be required to reset. The EHPS module shall withstand voltages up to a transient voltage of 58 volts for 400 milliseconds. If the supply voltage exceeds 55 volts, the EHPS module drives shall shut down and a key cycle will be required to reset. The 36 volts power supply is grounded directly to the negative terminal of the EHPS.
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
The EHPS 36-volt supply voltage is out of range (less than 18 volts or greater than 55 volts).
Action Taken When DTC Sets
| • | System operation is reduced. |
| • | The SERVICE BRAKE SYSTEM message and SERVICE STEER SYSTEM message will be displayed. |
| • | A chime will sound. |
| • | EHPS module operation is normal, but the electric motor control is inactive. |
| • | Stores a DTC C0895 in the powertrain control module (PCM). |
| • | History DTC C0895 will be set in PCM. |
Conditions for Clearing the DTC
| • | EHPS supply voltage comes back within range (greater than 22 volts or less than 53 volts). |
| • | Using the scan tool. |
| • | A history DTC will clear after 255 consecutive ignition cycles is the condition for the malfunction is no longer present. |
Diagnostic Aids
| • | Fault is disabled when Battery Disconnect is active. |
| • | Inline 125 A fuse may be open. |
| • | 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.
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Test to see if fault is intermittent.
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Test to see if voltage and ground circuits from starter/generator control module (SGCM) are good.
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Test voltage circuit for short to ground or open.
-
Test ground circuit for short to voltage or open.
-
Test for poor connection at power connector.
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 electro-hydraulic power steering (EHPS) Diagnostic System Check? | -- | Go to Step 2 | |
Is the EHPS voltage within the required range? | 18-55 V | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
Is voltage reading between the required range? | 18-55 V | Go to Step 6 | Go to Step 4 | |
Test the 42-V supply circuit for an intermittent short to ground or an open. Refer to Testing for Electrical Intermittents and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 5 | |
Test the 42-volt ground circuit for an intermittent short to voltage or an open. Refer to Testing for Electrical Intermittents and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 | |
Inspect for poor connections at the harness connector of the EHPS control module. 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 9 | Go to Step 8 | |
7 | Replace the starter/generator control module (SGCM). Refer to Generator Control Module Replacement in Engine Electrical. Is replacement complete? | -- | Go to Step 9 | -- |
8 |
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 . Is replacement complete? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
