For 1990-2009 cars

# DTC P0603 May Be Stored When Battery Voltage is Removed From the PCM wiht Ignition Off

Subject: | DTC P0603 (PCM Long Term Memory Reset) May Be Stored When Battery Voltage is Removed From the PCM With Ignition Off (Clear Diagnostic Trouble Codes and Retest). This Bulletin Also Includes a Service Manual Update.

Models: | 2000-2001 S-Series vehicles equipped with automatic transaxles (RPO MP6/MP7)

### Condition

DTC P0603 may be stored when battery voltage is removed from the PCM. The 2000/2001 S-Series Engine Service Manual indicates to replace the PCM for DTC P0603. This DTC does not necessarily indicate that the PCM requires replacement.

### Cause

The PCM may incorrectly detect a memory error when battery voltage is removed from the PCM with the ignition Off. When this condition occurs, the diagnostic for DTC P0603 will record a FAILED and PASSED status.

### Correction

Follow procedure in this bulletin to correct DTC P0603.

Please obtain all the 2000/2001 S-Series Engine Service Manuals at your location and make the necessary update as indicated below.

On page 274, next to the title for DTC P0603, write in the following:

"Refer to Technical Bulletin 00-T-55"

### Procedure:

1. Check for DTCs and record any that indicate FAILED status.

Important: DTC P0603 is a type "D" code and will not illuminate the Malfunction Indicator lamp (MIL) SERVICE ENGINE SOON (SES) or SERVICE WRENCH telltale. If the concern is for a SES or SERVICE WRENCH telltale, be sure to diagnose those DTC that illuminate the telltale.

2. Clear DTCs.
3. Cycle ignition switch.
4. Verify that the DTC P0603 LAST TEST does not indicate FAILED. If DTC P0603 LAST TEST indicates FAILED, replace PCM.