GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Vivant 🢒 Engine 🢒 Engine Controls - 2.0L (L34 GMDAT) 🢒 DTC 053

Circuit Description

When the ignition is turned ON, the key is tested by the immobilizer anti-theft system. While the key code is being read by the immobilizer control unit, the engine can start and run with any key that will turn the lock cylinder. The key code is read and compared with the key codes that have been stored in the memory of the immobilizer control unit. If a valid key is detected, the immobilizer control unit sends a serial data release message to the engine control module (ECM). Included in the release message is an identification (ID) code which assures that neither the immobilizer control unit nor the ECM have been substituted to defeat the system. If the ECM receives an invalid release message, the ECM performs the following actions:

    • Disables the fuel injector circuit
    • Disables the fuel pump circuit
    • Disables the ignition coil

Conditions for Setting the DTC
    • The ECM does not receive the signal from the immobilizer control module within 0.9 seconds when the vehicle is stationary, or within 1.8 seconds when the vehicle is moving.
    • The ECM receives an incorrect release message from the immobilizer control unit more than 5 times.

The above conditions will be maintained until the ignition is switched to LOCK.

Conditions for Clearing the MIL/DTC

The ignition switch is turned to LOCK, or the scan tool TROUBLE CODE CLEAR command is issued.

Step

Action

Yes

No

1

Connect the scan tool using the following procedure:

  1. Insert the immobilizer data cartridge into the scan tool.
  2. Turn the ignition switch to LOCK.
  3. Connect the scan tool to the data link connector (DLC).
  4. Connect the scan tool's power cord to the cigar lighter socket.
  5. Turn ON the ignition, but do not start the engine.

Is communication established between the scan tool and the immobilizer control unit?

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent in Theft Deterrent

2

Select IMMOBILIZER DIAGNOSIS STATUS from the scan tool menu.

Does the KEY STATUS message indicate THIS KEY IS GOOD?

Go to Step 3

Go to Key Status Errors in Theft Deterrent

3
  1. Select IMMOBILIZER DIAGNOSIS STATUS from the scan tool menu.
  2. Read the IMMO & ECM ID-CODE message.

Does the message ID-CODES ARE SAME appear?

Go to Step 4

Go to Programming Theft Deterrent System Components in Theft Deterrent

4

Inspect for an open serial data wire between the immobilizer control unit and the engine control module (ECM).

Is the circuit open?

Go to Step 5

Go to Step 6

5

Repair the open serial data wire between the ECM and the immobilizer control unit.

Did you complete the repair?

System OK

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6
  1. Replace the ECM.
  2. Reprogram the identification (ID) code. Refer to Programming Theft Deterrent System Components in Theft Deterrent

Is the repair complete?

System OK

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