For 1990-2009 cars

### Circuit Description (Domestic)

The driver door key is located at the driver door latch assembly. The driver door key cylinder switch contacts, which are normally open, receive a constant ground via the ground circuit. When the door key is turned to unlock position, the switch contacts close and the DDM detects a switched ground. The DDM sends a message via GMLAN serial data to the RCDLR, indicating the key cylinder unlock switch request. The RCDLR is the master of all lock and unlock operations. If the RCDLR determines that the key cylinder unlock switch request is valid and conditions are correct for the door modules to perform the unlock function, it sends a message via GMLAN serial data back to all door modules to unlock all doors. For more detailed information concerning power door lock operation refer to Power Door Locks Description and Operation .

### DTC Descriptors

This diagnostic procedure supports the following DTCs:

• | DTC B3062 Front Door Key Lock Switch Circuit

• | DTC B3067 Front Door Key Unlock Switch Circuit

This vehicle has DTCs which include DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description .

DTC Symptom | DTC Symptom Descriptor
--- | ---
02 | Short to Ground

### Conditions for Running the DTC

• | The DDM must be powered.

• | DTC B1325 Battery Voltage Out of Range, must not be current.

### Conditions for Setting the DTC

The DDM detects that the door key lock/unlock switch is closed for more than 30 continuous seconds.

### Action Taken When the DTC Sets

The DDM ignores inputs from the key cylinder switch until the switch changes state.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | You issue a scan tool CLEAR DTCs command.

• | After 40 consecutive warm-up cycles without failure, the history DTC will be cleared.

### Diagnostic Aids

An intermittently sticking key cylinder switch can cause this DTC to set. Thoroughly inspect the circuit and connectors. An incomplete inspection of the circuit and connectors may result in misdiagnosis, causing the reappearance of the malfunction after the part replacement. If an intermittent exists, refer to Testing for Intermittent Conditions and Poor Connections .

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Door Lock/Indicator Schematics Connector End View Reference: Vehicle Access Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe the Door Cylinder Switch parameter in the driver door module (DDM) data list.

Does the scan tool display Idle?

Go to Step 3

Go to Step 4

3 |

1. Insert the door key into the driver door lock cylinder.
2. Turn and hold the key to the Unlock position for 3 seconds or longer.
3. With the scan tool, observe the Door Cylinder Switch parameter.

Does the Key Cylinder Switch parameter change to the unlock state?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 4

4 |

1. Turn OFF the ignition.
2. Disconnect the driver door latch assembly harness connector.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool, observe the Door Cylinder Switch parameter.

Does the scan tool display Idle?

Go to Step 7

Go to Step 5

5 | Test the driver door key switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 6
6 | Inspect for poor connections at the DDM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 8
7 | Inspect for poor connections at the driver door latch assembly harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9
8 | Replace the DDM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | --
9 | Replace the driver door latch assembly. Refer to Front Side Door Outside Handle Replacement . Did you complete the replacement? | Go to Step 10 | --
10 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK