Electro-Hydraulic Power Steering Pump Electrical Test

Electro-Hydraulic Power Steering Pump Electrical Test

The following test steps must be performed in the given order. If a fault is found in one step, the subsequent steps can be skipped.

Tools Required

Scan Tool Tech 2

Important: Before proceeding with the steps below, ensure: There are no stored diagnostic trouble codes stored in electro-hydraulic power steering (EHPS).




Circuit System Verification
Battery Voltage

1. Ignition ON, Engine OFF, All accessories OFF, with a scan tool verify Battery Voltage range to be between 11-13.5 volts.
2. Ignition ON, Engine starting, Battery Voltage to be greater than 8 volts.
3. Engine ON, All accessories OFF, battery voltage range to be between 12-14.5 volts.
4. Turn steering wheel right until stop, turn slightly further and hold firmly in this position. The voltage range should be between 11-14 volts.

• If the voltage is less than the specified range, test Connector X2 terminal 2 (Battery Ground) of the Power Steering Module for a short to ground or an open/high resistance.


• If the voltage is more than the specified range, test Connector X2 terminal 2 (Battery Ground) of the Power Steering Module for a short to voltage.


• If the circuit tests normal, refer to Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) .


Actual Pump Motor Current

1. Ignition OFF, Wait 3 seconds, Ignition ON, All accessories OFF with a scan tool verify pump motor amperage to be 0 Amps
2. Ignition ON, Engine ON, All accessories OFF, Battery Voltage range to be between 4-9 Amps.
3. Turn steering wheel right until stop, turn slightly further and hold firmly in this position. The amperage range should be between 55-65 Amps.
4. Turn steering wheel left until stop, turn slightly further and hold firmly in this position. The amperage range should be between 55-65 Amps.

• If the amperage is not within the specified range, replace the power steering control module.


• If the amperage is within the specified range, refer to desired pump speed.


Desired Pump Speed

1. Ignition OFF, Wait 3 seconds, Ignition ON, All accessories OFF with a scan tool verify engine RPM is 0.
2. Engine Running, with a scan tool verify engine RPM to be 2660.

• If the RPM is not specified value, replace the power steering control module.


• If the RPM is the specified value, refer to the Actual Pump Speed.


Actual Pump Speed

1. Ignition OFF, Wait 3 seconds, Ignition ON, All accessories OFF, with a scan tool verify the engine RPM to be 0.
2. Engine Running, with a scan tool verify engine RPM range to be 2655-2665 RPM.

• If the RPM is not within the specified range, replace the power steering control module.