GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Aveo 🢒 Engine 🢒 Engine Controls - 1.2L 🢒 Malfunction Indicator Lamp (MIL) Always On

Circuit Description

When the ignition switch is turned ON, the malfunction indicator lamp (MIL) will be turned ON and remain ON until the engine is running, if no DTCs are stored. Battery voltage is supplied through the ignition switch directly to the MIL telltale. The engine control module (ECM) controls the MIL by providing a ground path through the MIL control circuit to turn ON the MIL.

Test Description

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

  1. The Diagnostic System Check-Engine Controls 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 stored in the scan tool for later reference.

    2.

  2. When the ignition is turned ON, the MIL should be turned ON and remain ON until the engine is running or if an emission related DTC is stored. This step inspects the ability of the ECM to control the MIL. The scan tool has the ability to command the MIL ON and OFF.

    3.

  3. A shorted MIL circuit can be diagnosed with a scan tool.

    4.

  4. The replacement ECM must be reprogrammed. Refer to the latest Techline information for reprogramming procedures.

Step

Action

Yes

No

1

Perform the Diagnostic System Check - Engine Controls.

Is the check complete?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Turn the ignition switch to LOCK.
  2. Install the scan tool to the data link connector (DLC).
  3. Command the malfunction indicator lamp (MIL) ON and OFF.

Does the MIL turn ON and OFF when commanded?

Go to Step 7

Go to Step 3

3
  1. Turn the ignition switch to LOCK.
  2. Disconnect the engine control module (ECM) connector.
  3. Turn the ignition switch to ON.

Is the MIL OFF?

Go to Step 6

Go to Step 4

4

Inspect the MIL control circuit for a short to ground and repair, as needed.

Is the repair complete?

Go to Step 7

Go to Step 5

5

Replace the instrument panel cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Is the replacement complete?

Go to Step 7

--

6

Replace the ECM. Refer to Engine Control Module Replacement .

Is the replacement complete?

Go to Step 7

--

7
  1. Using the scan tool, clear the DTCs.
  2. Attempt to start the engine.

Does the engine start and continue to run?

Go to Step 8

Go to Step 1

8
  1. Allow the engine to idle until normal operating temperature is reached.
  2. Check if any DTCs are set.

Are any DTCs displayed that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK