GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The power steering control module (PSCM) has a discrete battery positive voltage supply circuit. The PSCM monitors the voltage level on this circuit to ensure the power steering system has adequate voltage levels to perform the system functions.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0899 Device 1 Voltage Low

This vehicle has DTCs which include DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description .

DTC Symptom

DTC Symptom Descriptor

03

Voltage Below Threshold

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

Power steering system voltage is less than 9 volts for at least one second.

Action Taken When the DTC Sets

    • DTC C0899 03 is stored in memory.
    • The driver information center (DIC) displays the POWER STEERING warning message.
    • No steering assist is provided.

Conditions for Clearing the DTC

    • A current DTC will clear when the malfunction is no longer present.
    • A history DTC will clear after 100 consecutive malfunction-free ignition cycles.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests if the voltage malfunction exists in the power steering system.

Step

Action

Values

Yes

No

Schematic Reference: Power Steering Schematics

Connector End Views Reference: Power Steering Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, observe the Battery Voltage parameter in the Power Steering Data List.

Does the scan tool indicate that the Battery Voltage parameter is greater than the specified value?

9 V

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Inspect for poor connections at the underhood fuse block stud ring terminal. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 4

4

Inspect for poor connections at the ground terminal G103 . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 5

5

Inspect for poor connections at the 80-amp EPS fuse in the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the power steering control module (PSCM) harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

7

Test the battery positive voltage circuit of the PSCM for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

8

Test the ground circuit of the PSCM for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

9

Replace the power steering motor and module assembly. Refer to Power Steering Assist Motor Replacement .

Did you complete the replacement?

--

Go to Step 10

--

10

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC.

Does DTC C0899 reset?

--

Go to Step 2

System OK