GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Corvette 🢒 Steering 🢒 Steering Wheel and Column 🢒 Electronic Column Lock Does Not Unlock

Diagnostic Aids
    • An internally open or shorted steering column lock relay may cause the column to not unlock.
    • An open on the key in ignition switch signal circuit will intermittently cause the column to not unlock.
    • Disconnecting or opening the steering column lock feedback circuit will cause the body control module (BCM) to enter Fail Enable Standby mode. The steering column will remain inoperative until the Fail Enable Standby mode is cleared. To clear this mode, disconnect the BCM1 &instrument panel cluster (IPC) fuse in the instrument panel (I/P) fuse block for 15 seconds.

Methods to free a stuck electric column lock:

    •  Run the engine at a high idle if the battery is low. Use the scan tool output controls to try to unlock the column.
    • Torque the steering wheel back and forth against the column lock bolt.
    • Turn the air conditioner vents toward the steering column to cool the lock motor.
    • Connect a battery charger directly to the lock motor leads and use the highest voltage setting.
    • Connect a battery in series with a battery charger directly to the lock motor leads. Start at the lowest voltage setting. Do not exceed 28 volts for 1 second maximum.

Test Description

  1. In 2001-2004 cars the Column Lock State will be System Disabled if the BCM is calibrated for a domestic automatic transmission, and the steering column lock system will not operate.

    2.

  2. The column lock motor should operate for less than one second when the ignition is turned ON, and after a one second delay when the key is removed from the ignition.

    3.

  3. The external steering column lock relay is located above the BCM, in the passenger footwell area, behind the front kick-up panel. The external steering column lock relay can be identified by 2 orange wires connected to it. There may be either 2 or 3 relays in this area, and they may not always be in the same position.

    4.

  4. Turn the ignition ON and then OFF and move the ignition key out only enough to enter pre-lock mode. Move the ignition key until the scan tool displays both the Key in Ignition and Key Out of Ignition switches are Inactive, and the Column Lock State is Detect Key Out. This will energize both of the BCMs internal relays, and should apply 12 volts to the lock and unlock circuits.

    5.

  5. Test the key out ignition switch signal circuit between the two BCM connectors when testing this circuit for an open.

Step

Action

Yes

No

Schematic Reference: Column/Ignition Lock Schematics

Connector End View Reference: Steering Wheel and Column Connector End Views

1

Did you perform the Steering Wheel and Column Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Steering Wheel and Column

2

Turn the ignition ON.

Does the steering column unlock?

Go to Diagnostic Aids

Go to Step 3

3

Observe the Column Lock State in the body control module (BCM) Input Data 2 List with a scan tool.

Does the scan tool display Enable Standby?

Go to Step 50

Go to Step 4

4

Does the scan tool display powertrain control module (PCM) F.E. Stdby?

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

Go to Step 5

5

Does the scan tool display System Disabled?

Go to Step 49

Go to Step 6

6
  1. Observe Key in Ignition with the scan tool.
  2. Insert the key into the ignition.
  3. Remove the key from the ignition.

Does the scan tool display Key in Ignition Active when the key is in the ignition, and Inactive when the key is removed from the ignition?

Go to Step 7

Go to Step 39

7
  1. Observe Key Out of Ign with the scan tool.
  2. Insert the key into the ignition.
  3. Remove the key from the ignition.

Does the scan tool display Key Out of Ign Inactive when the key is in the ignition, and Active when the key is removed from the ignition?

Go to Step 8

Go to Step 41

8
  1. Cycle the ignition ON and OFF, and remove the key from the ignition.
  2. Listen to the column lock motor.

Does the column lock motor operate when the ignition is turned ON and one second after the key is removed?

Go to Step 9

Go to Step 13

9
  1. Cycle the ignition ON and OFF, and remove the key from the ignition.
  2. Observe the Column Feedback with the scan tool.

Does the scan tool always display Active?

Go to Step 10

Go to Step 11

10
  1. Remove the knee bolster. Refer to Driver Knee Bolster Panel Replacement in Instrument Panel, Gages, and Console.
  2. Disconnect the steering column lock connector.
  3. Observe the Column Feedback with the scan tool.

Does the scan tool display Inactive?

Go to Step 58

Go to Step 38

11
  1. Remove the knee bolster. Refer to Driver Knee Bolster Panel Replacement in Instrument Panel, Gages, and Console.
  2. Disconnect the steering column lock connector.
  3. Test the steering column lock feedback switch ground circuit for an open.

Did you find and correct the condition?

Go to Step 60

Go to Step 12

12
  1. Jumper the steering column lock signal circuit to a good ground.
  2. Observe the Column Feedback with the scan tool.

Does the scan tool display Active?

Go to Step 58

Go to Step 34

13
  1. Remove the knee bolster. Refer to Driver Knee Bolster Panel Replacement in Instrument Panel, Gages, and Console.
  2. Disconnect the steering column lock connector.
  3. Measure the resistance between the steering column lock motor and a good ground.

Is the resistance greater than 10K ohms?

Go to Step 14

Go to Step 58

14
  1. Connect a test lamp between the steering column lock and unlock circuits.
  2. Cycle the ignition ON and OFF, and remove the key from the ignition.

Does the test lamp illuminate momentarily when the ignition is turned ON and again one second after the key is removed?

Go to Step 47

Go to Step 15

15
  1. Probe the steering column unlock circuit with a test lamp connected to a good ground.
  2. Cycle the ignition ON and OFF, and remove the key from the ignition.

Does the test lamp illuminate momentarily when the ignition is turned ON?

Go to Step 16

Go to Step 25

16
  1. Remove the key from the ignition.
  2. Probe the steering column unlock circuit with a test lamp connected to B+.

Does the test lamp illuminate?

Go to Step 17

Go to Step 43

17

Probe the steering column lock circuit with a test lamp connected to B+.

Does the test lamp illuminate?

Go to Step 18

Go to Step 30

18
  1. Remove the front kick-up panel on the passenger side.
  2. Probe the BCM2 voltage supply circuit at the back of the external steering column lock relay with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 19

Go to Step 55

19
  1. Turn the ignition ON and then OFF.
  2. Pull the ignition key out only far enough to enter Detect Key Out pre-lock mode.
  3. Probe the steering column lock circuit to the BCM at the back of the relay with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 20

Go to Step 32

20

Probe the steering column unlock circuit at the back of the relay with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 21

Go to Step 33

21

Probe the external steering column lock relay control at the back of the relay with a test lamp connected to a good ground.

Does the relay click?

Go to Step 22

Go to Step 24

22
  1. Probe the external steering column lock relay control circuit at the back of the relay with a test lamp connected to B+.
  2. Cycle the ignition ON and OFF and remove the ignition key.

Does the test lamp illuminate momentarily?

Go to Step 23

Go to Step 35

23
  1. Remove the ignition key.
  2. Probe the steering column lock circuit to the BCM at the back of the relay with a test lamp connected to B+.

Does the test lamp illuminate?

Go to Step 45

Go to Step 36

24

Probe the external steering column lock relay control at the back of the relay with a test lamp connected to B+.

Does the test lamp illuminate?

Go to Step 37

Go to Step 45

25

Test the steering column unlock circuit for an open between the BCM and the lock motor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 26

26

Inspect the BCM2 fuse.

Was the fuse open?

Go to Step 27

Go to Step 36

27
  1. Remove the key from the ignition.
  2. Disconnect the BCM C3 connector.
  3. Measure resistance between the column unlock circuit at the BCM and a good ground.

Is the resistance greater than 10K ohms?

Go to Step 28

Go to Step 51

28

Measure resistance between the column lock circuit at the BCM and a good ground.

Is the resistance greater than 10K ohms?

Go to Step 29

Go to Step 52

29

Measure resistance between the BCM2 voltage supply circuit at the BCM and a good ground.

Is the resistance greater than 10K ohms?

Go to Step 59

Go to Step 53

30

Test the steering column lock circuit for an open between the external relay and the lock motor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 31

31

Test the steering column unlock circuit for an open between the BCM and the external relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 45

32

Test the steering column lock circuit for an open between the BCM and the external relay. Refer to Circuit Testing and Wiring Repairs in Wiring Repairs.

Did your find and correct the condition?

Go to Step 60

Go to Step 48

33

Test the steering column unlock circuit for an open between the BCM and the external relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 48

34

Test the steering column lock signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 48

35

Test the steering column lock relay control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 36

36

Test the BCM2 voltage supply circuit and the BCM power ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 60

Go to Step 48

37

Test the steering column lock relay control circuit for a short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 59

38

Test the steering column lock signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 59

39
  1. Disconnect the ignition switch connector.
  2. Momentarily jumper the key in ignition switch signal circuit to a good ground.
  3. Observe Key in Ignition with the scan tool.

Does the scan tool indicate Key in Ignition Active when jumpered and Inactive when not jumpered?

Go to Step 42

Go to Step 40

40

Test the key in ignition switch signal circuits for the following:

    • An open
    • A short to ground
    • A short to voltage

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 48

41
  1. Disconnect the ignition switch connector.
  2. Momentarily jumper the key out ignition switch signal circuit to a good ground.
  3. Observe Key Out of Ign with the scan tool.

Does the scan tool indicate Key Out of Ign Active when jumpered and Inactive when not jumpered?

Go to Step 42

Go to Step 43

42

Test the ignition switch ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 46

43

Test the key out ignition switch signal circuits for the following:

    • An open
    • A short to ground
    • A short to voltage

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 44

44

Test the following for a short to ground:

    • The steering column lock circuit
    • The steering column unlock circuit
    • The steering column lock motor

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did your find and correct the condition?

Go to Step 60

Go to Step 48

45

Inspect the steering column lock relay connector for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 60

Go to Step 56

46

Inspect the ignition switch connector for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 60

Go to Step 57

47

Inspect the steering column lock connector for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 60

Go to Step 58

48

Inspect the BCM connector for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 60

Go to Step 59

49

Inspect the BCM for correct Transmission and Export calibrations with the scan tool.

Go to Step 60

--

50
  1. Disconnect the BCM1 & instrument panel cluster (IPC) fuse in the instrument panel (I/P) fuse block for 15 seconds.
  2. Reconnect the BCM1 & IPC fuse.

Did you complete the action?

Go to Step 60

--

51

Repair the short in the steering column unlock circuit or in steering column lock circuit between external steering column lock relay and steering column lock motor connector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 54

--

52

Repair the short in the steering column lock circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 54

--

53

Repair the short in the BCM2 voltage supply circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 54

--

54
  1. Reconnect the BCM C3 connector.
  2. Replace the BCM2 fuse.

Did BCM2 fuse open again?

Go to Step 59

Go to Step 60

55

Repair the open in the steering column lock relay voltage supply circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 60

--

56

Replace the steering column lock relay.

Did you complete the replacement?

Go to Step 60

--

57

Replace the ignition switch. Refer to Ignition and Start Switch Replacement in Instrument Panel, Gages, and Console.

Did you complete the replacement?

Go to Step 60

--

58
  1. Inspect the BCM2 fuse and replace if open.
  2. Replace the steering column lock. Refer to Steering Wheel Theft Deterrent Lock Replacement .

Did you complete the replacement?

Go to Step 60

--

59

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 60

--

60
  1. Replace the BCM2 fuse if removed or open.
  2. Reconnect the Steering Column Lock connector if disconnected.
  3. Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2