GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Schematic Reference: Keyless Entry Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic Trouble Code (DTC) List - Vehicle

2

Verify the fault is present.

Does the system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Close and lock the doors.
  2. Insert the Remote Coded Key into the driver door lock.
  3. Turn the key to unlock and lock the door.

Do all the doors unlock and lock?

--

Go to Step 4

Go to Symptoms - Doors in Doors

4

  1. Unlock the driver door with the key.
  2. With the theft deterrent LED flashing, insert the key into the ignition switch and turn the ignition ON.

Does the theft deterrent LED turn OFF?

--

Go to Step 5

Go to Symptoms - Theft Deterrent in Theft Deterrent

5

  1. Lock the driver door with the key.
  2. Remove the key from the driver door lock.
  3. Operate the key Unlock button within 2 meters of the drivers door B-pillar.

Does the driver door unlock (2-stage unlock) or all the doors unlock (single-stage unlock)?

--

Go to Step 6

Go to Step 10

6

When performing Step 5, did all of the following occur when the key Unlock button was pressed:

    • Indicators flashed twice
    • Dome lamp illuminated.
    • Theft deterrent LED turned OFF?

--

Go to Step 7

Go to Symptoms - Theft Deterrent in Theft Deterrent

7

  1. Close all the doors.
  2. Operate the Lock button on the key within 2 meters of the driver door B-pillar.

Do the doors lock?

--

Go to Step 8

Go to Step 10

8

When performing Step 7, did all of the following occur when the key Lock button was pressed:

    • Theft deterrent LED began flashing
    • Indicators flashed once
    • Dome lamp turned OFF if illuminated, ensure switch is in Door position?

--

Go to Step 9

Go to Symptoms - Theft Deterrent in Theft Deterrent

9

Stand within 2 meters of the rear of the vehicle and press the remote key's Rear Compartment Release button for 2 seconds.

Does the rear compartment lid unlock?

--

System OK

Go to Step 10

10

  1. Connect the scan tool to the data link connector (DLC).
  2. Select Diagnostics/Model Year/Vehicle Model/Body/Body Control Module/Data Display
  3. Operate the Unlock, Lock and Trunk Lid Release buttons on the key.

Are the values as specified?

Valid Key

Go to Step 16

Go to Step 11

11

  1. On another vehicle with a fully functional key and receiver, connect a scan tool to the DLC.
  2. Select Remote Key Status as per Step 10.
  3. Operate the Unlock, Lock and Trunk lid release buttons on the key.

Are the values as specified?

Invalid Code

Go to Step 12

Go to Step 17

12

  1. Return to the original vehicle which has the suspected faulty remote coded key/receiver.
  2. Back-probe the remote receiver module battery positive feed circuit with a voltmeter to ground.

Is the value as specified?

B+

Go to Step 13

Go to Step 18

13

Test continuity of the ground circuit between the body control module (BCM) and the remote receiver module with an ohmmeter. Refer to Testing for Continuity .

Is the indicated value less than the value specified?

1 ohms

Go to Step 14

Go to Step 19

14

Test continuity of the remote receiver data output circuit between the BCM and the remote receiver with an ohmmeter. Refer to Testing for Continuity .

Is the indicated value less than the value specified?

1 ohms

Go to Step 15

Go to Step 20

15

  1. Replace the remote receiver module with a known functional remote receiver module.
  2. Connect the scan tool to the DLC.
  3. Select Body/Body Control Module/Data Display
  4. Operate the Unlock, Lock and Trunk Lid release button on the remote coded key.

Does the scan tool display each request?

--

Go to Step 21

Go to Step 16

16

Correct signal, replace the BCM. Refer to Body Control Module Replacement .

Did you complete the repair?

--

Go to Step 22

--

17

Program a new key to the original vehicle. Refer to Replacing Keys in Theft Deterrent.

Did you complete the repair?

--

Go to Step 22

--

18

Inspect and repair the remote receiver module battery positive feed circuit. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 22

--

19

Repair the ground circuit between the BCM and the remote receiver module. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 22

--

20

Repair the remote receiver data output circuit between the BCM and the remote receiver. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 22

--

21

Replace the remote receiver module. Refer to Remote Control Door Lock Receiver Replacement .

Did you complete the repair?

--

Go to Step 22

--

22

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 1