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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2001 🢒 Catera 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 DTC P0603

Circuit Description

The engine control module (ECM) contains data that is essential to running the engine. The ECM continuously checks the integrity of this data.

Conditions for Running the DTC

During the engine power down phase the ECM performs this test.

Conditions for Setting the DTC

The ECM determines that an internal data test did not pass.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

This diagnostic trouble code (DTC) may set if the battery is disconnected while the ECM is powered-up. This DTC and several others may set if the switched B+ or the battery supply is removed from the ECM while the ECM is powered up. Test for intermittent or poor connections on the switched B+ and the battery supply circuits at the ECM. Also test the control circuit for the engine controls power relay for in intermittent open or high resistance and inspect the terminal contact at the relay. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

DTC P0603 - Control Module Long Term Memory Reset

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition and wait 60 seconds.
  3. Turn ON the ignition and check the DTC Information.

Did this DTC set?

Go to Step 3

Go to Diagnostic Aids

3

Important: 

   • Perform the idle learn procedure when replacing the ECM or throttle body.
   • This vehicle is equipped with a theft deterrent system that interfaces with the ECM. Program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle.

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the action?

Go to Step 4

--

4
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

Go to Step 5

Go to Step 2

5

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK