For 1990-2009 cars

### Circuit Description

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

### Conditions for Running the DTC

The ECM is powered up.

### Conditions for Setting the DTC

The ECM is unable to correctly read data from the flash memory.

### Action Taken When the DTC Sets

• | The ECM illuminates the malfunction indicator lamp (MIL) on the first drive trip that the diagnostic runs and fails.

• | The ECM attempts to record the operating conditions in the Freeze Frame, however since this diagnostic trouble code (DTC) indicates that an internal ECM test did not pass, this information may not be useful for this specific DTC.

### Conditions for Clearing the MIL/DTC

• | The ECM turns OFF the MIL after three consecutive drive trips that the diagnostic runs and passes.

• | A History DTC clears after forty consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic.

• | The scan tool clears the MIL/DTC.

### Diagnostic Aids

Ensure the engine controls power relay was not removed while the ignition was ON. This DTC and several others will set if the Switched B+ voltage is removed from the ECM while the ECM is powered up. Test for intermittent or poor connections on the switched B+ 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 P0601 - ECM Memory

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Clear DTC information using the scan tool.
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/Programming .

Is the action complete?

--

Go to Step 4

--

4 |

1. Using the scan tool, clear the DTCs.
2. Start the engine.
3. Allow the engine to idle until the engine reaches the normal operating temperature.
4. Select DTC and the Specific DTC function.
5. Enter the DTC number that was set.
6. Operate the vehicle within the Conditions for Running this DTC until the scan tool indicates that the diagnostic Ran.

Does the scan tool indicate that the diagnostic Passed?

--

Go to Step 5

Go to Step 2

5 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to the applicable DTC table | System OK