GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Aveo 🢒 Engine 🢒 Engine Controls - 1.2L 🢒 Diagnostic System Check - Engine Controls

Circuit Description

The On-Board Diagnostic System Check is the starting point for any driveability complaint diagnosis. Before using this procedure, perform a careful visual/physical inspection of the engine control module (ECM) and the engine grounds for cleanliness and tightness.

The Diagnostic System Check is an organized approach to identifying a problem created by an electronic engine control system malfunction.

Diagnostic Aids

An intermittent may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Inspect for poor connections or a damaged harness. Inspect the ECM harness and connections for improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness.

Test Description

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

  1. The malfunction indicator lamp (MIL) should be ON steady with the ignition ON and the engine OFF. If not, go to Diagnostic Aids.

    2.

  2. Checks the Serial 2 data circuit and ensures that the ECM is able to transmit serial data.

    3.

  3. This test ensures that the ECM is capable of controlling the MIL and the MIL driver circuit is not shorted to ground.

    4.

  4. A scan tool parameter which is not within the typical range may help to isolate the area which is causing the problem.

    5.

  5. This vehicle is equipped with a ECM which utilizes an electrically erasable programmable read only memory (EEPROM). The replacement ECM must be programmed. Refer to the latest Techline procedure for ECM reprogramming.

Step

Action

Yes

No

1

  1. Turn the ignition switch to ON.
  2. Observe the malfunction indicator lamp (MIL).

Does the MIL illuminate?

Go to Step 2

Go to Malfunction Indicator Lamp (MIL) Inoperative

2

  1. Turn the ignition switch to LOCK.
  2. Install the scan tool to the data link connector (DLC).
  3. Turn the ignition switch to ON.
  4. Attempt to display the engine control module (ECM) engine data with the scan tool.

Does the scan tool display the ECM engine data?

Go to Step 3

Go to Step 8

3

  1. Using the scan tool output test function, select the MIL control and command the MIL OFF.
  2. Observe the MIL.

Does the MIL turn OFF?

Go to Step 4

Go to Malfunction Indicator Lamp (MIL) Always On

4

Attempt to start the engine.

Does the engine start and continue to run?

Go to Step 5

Go to Engine Cranks but Does Not Run

5

Select DISPLAY DTC with the scan tool.

Are any DTCs stored?

Go to Step 6

Go to Step 7

6

View the display for DTCs P0107, P0108, P0113, P0118, P0122, or P0123.

Are 2 or more of the DTCs stored?

Go to Multiple Engine Control Module Information Sensor DTCs Set

Go to applicable DTC table

7

Compare the ECM data values displayed on the scan tool to the typical engine scan data values.

Are the displayed values normal or close to the typical values?

Go to Engine Control Module Outputs Diagnosis

Go to indicated component system check

8
  1. Turn the ignition switch to LOCK.
  2. Disconnect the ECM connector.
  3. Turn the ignition switch to ON.
  4. Test the serial data circuit for an open, short to ground, or short to voltage. Also test the DLC ignition feed for an open or short to ground, and test the DLC ground circuits for an open.

Is a repair necessary?

Go to Step 9

Go to Step 10

9

Repair the open, short to ground, or short to voltage in the serial data circuit or the DLC ignition feed circuit.

Did you complete the repair?

System OK

--

10

  1. Attempt to reprogram the ECM.
  2. Attempt to display the ECM data with the scan tool.

Does the scan tool display ECM engine data?

Go to Step 2

Go to Step 11

11

Replace the ECM.

Did you complete the replacement?

System OK

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