For 1990-2009 cars

### Circuit Operation

As part of its normal processing, the power steering control module (PSCM) performs data checks to RAM on a continious basis. Certain data is stored in RAM until it is summoned by the microprocessor or superseded by more recent data. Data stored in RAM is erased when the system is switched off.

### Conditions for Setting the DTC

DTC 23 is an internal PSCM fault (RAM defect).

### Action Taken When the DTC Sets

Power steering assist will default to partial manual steering effort.

### Conditions for Clearing the DTC

Replacing the power steering control module.

### Diagnostic Aids

• | Before replacing the PSCM, test the power circuit (BRN wire) and ground circuit (BLK wire).

• | Perform a voltage drop test when testing the power and ground circuit. Refer to Testing for Voltage Drop in Wiring Systems.

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. This step checks for the proper voltage to the module. Proper voltage is needed by the module to operate properly.

2. This step checks for the proper ground to the module. A proper ground is needed by the module to operate properly.

3. This step replaces the power steering control module.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Variable Effort Steering System Check performed? | -- | Go to Step 2 | Go to Variable Effort Steering System Check
2 |

1. Remove the power steering control module (PSCM).
2. Turn the ignition switch to the ON position.
3. Use a DMM to measure the voltage between terminal 6 of the PSCM connector and a known good ground.

Is the measured voltage within the specified value?

B+

Go to Step 4

Go to Step 3

3 |

1. Locate an open or a high resistance in circuit X83.
2. Repair the open or the high resistance in circuit X83.

Is the repair complete?

--

Go to Step 7

--

4 | Use the DMM to measure the resistance between terminal 8 of the PSCM connector and a known good ground. Is the measured resistance within the specified value? | Less than .5 ohms | Go to Step 6 | Go to Step 5
5 |

1. Locate an open or a high resistance in circuit F88.
2. Repair the open or the high resistance in circuit F88.

Is the repair complete?

--

Go to Step 7

--

6 | Replace the power steering control module. Is the replacement complete? | -- | Go to Step 7 | --
7 |

1. Connect all of the connectors and components that were disconnected.
2. Road test the vehicle.
3. Install the scan tool after the road test.
4. Check for DTC 23.

Is DTC 23 displayed?

--

Go to Variable Effort Steering System Check

System OK