GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Aveo 🢒 Engine 🢒 Engine Controls - 1.5L 🢒 DTC P0601

Circuit Description

The engine control module (ECM) is the control center of the fuel injection system. It constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the malfunction indicator lamp (MIL), and store a DTC or DTCs which identify the problem areas to aid the technician in making repairs. An electrically erasable programmable read only memory (EEPROM) is used to house the program information and the calibrations required for engine, transmission, and powertrain diagnostics operation. The ECM uses a value called a checksum for error detection of the software. The checksum is a value that is equal to all the numbers in the software added together. The ECM adds all the values in the software, and if that value does not equal the checksum value, a checksum error is indicated.

Conditions for Setting the DTC
    • The program ID is not equal to the value in the software.
    • The ignition switch is turned to ON.

Action Taken When the DTC Sets
    • The MIL will illuminate.
    • The ECM will attempt to record operating conditions at the time the failure is detected. However, since this is the internal ECM fault, this information may be or may not be reliable. This information will be stored in the Freeze Frame and Failure Records buffers.
    • A history DTC is stored.

Conditions for Clearing the MIL/DTC
    • The MIL turns OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault.
    • A history DTC will clear after 40 consecutive warm-up cycles without a fault.
    • DTCs can be cleared by using the scan tool.
    • Disconnect the ECM battery feed for more than 10 seconds.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. The On-Board Diagnostic System Check prompts the technician to complete some basic checks and store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.

    2.

  2. The replacement ECM must be programmed. Refer to the latest Techline procedure for ECM reprogramming.

Step

Action

Yes

No

1

Perform an On-Board Diagnostic System Check.

Was the check performed?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Turn the ignition OFF.
  2. Replace the engine control module (ECM). Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 3

--

3
  1. Using the scan tool, clear the DTCs.
  2. Start the engine and idle at normal operating temperature.
  3. Operate the vehicle within the Conditions for Setting the DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic has run and passed.

Go to Step 4

Go to Step 2

4

Are any DTCs displayed that have not been diagnosed?

Go to applicable DTC table

System OK