Circuit Description
The LH door switch circuit provides input to the LH Door Control Module (LDCM) when the switch is pressed to the LOCK or UNLOCK position. This input allows the LDCM to detect a door LOCK or UNLOCK request. The LDCM provides both power and ground to the door lock and unlock switches. When the LH door LOCK switch is pressed, a ground is supplied through the LH door switch to the LH door lock switch input which is pulled low. When the LDCM detects low voltage on the LH door lock switch input, the LDCM will LOCK the LH door and also send a message on the serial data line to the RH Door Control Module (RDCM) to LOCK the RH door. When the LH door UNLOCK switch is pressed, the LDCM will unlock the LH door and also send a second message on the serial data line to the RDCM to UNLOCK the RH door. The LDCM monitors both the LH door lock and unlock switch input circuits and determines how long a ground (switch pressed) has been applied. If the ground is applied for longer than expected, a malfunction is present and a DTC will set.
Conditions for Setting the DTC
| • | The LDCM detects a low voltage level (short to ground) at the LH door unlock switch input circuit. |
| • | Condition must be present for 20 seconds. |
Action Taken When the DTC Sets
| • | Stores a history DTC B2238 in the LDCM memory. |
| • | This DTC can only be set as a history code even if the malfunction is current. |
| • | No driver warning message will be displayed for this DTC. |
Conditions for Clearing the DTC
| • | The LDCM no longer detects a low voltage level (short to ground) at the LH door unlock switch input circuit for longer than 20 seconds. |
| • | Use the IPC clearing DTCs feature. |
| • | Use a scan tool. |
Diagnostic Aids
| • | The following conditions may cause an intermittent malfunction: |
| - | There is an intermittent short to ground in the LH door unlock switch input circuit (CKT 781). |
| - | The LH door unlock switch is shorted to ground internally or is sticking. |
| - | The LH door unlock switch was pressed for longer than 20 seconds. |
| • | If CKT 781 is shorted to ground or the LH door unlock switch is stuck closed, the LDCM and RDCM will continuously unlock both doors. |
| • | Using a scan tool, select LDCM inputs and monitor the door unlock switch status. If the scan tool displays ACTIVE, disconnect the LH door switch and check if the door unlock switch status changes to INACTIVE. If the status changed, then replace the LH door switch. If the status did not change, then check CKT 781 for a short to ground. |
| • | If the DTC does not reset after the code is cleared, then the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to Intermittents and Poor Connections . |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
This test determines the status of the LH door unlock switch using a scan tool. The scan tool will display the LH door unlock switch status as ACTIVE (button pressed) and INACTIVE (button released).
-
This test checks if the LH door unlock switch is shorted to ground or stuck. If the LH door unlock switch status changes from ACTIVE to INACTIVE when the LH door unlock switch is disconnected, then the LH door switch assembly must be replaced.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Were you sent here from the Power Door Diagnostic System Check? | -- | ||
Using a scan tool, select LDCM input display and monitor the door unlock switch status. Does the scan tool display door unlock switch status as ACTIVE? | -- | |||
Does the scan tool display door unlock switch status as ACTIVE? | -- | |||
4 | Check for a short to ground in CKT 781. Was a problem found and repaired? | -- | ||
5 | Replace the LH door switch assembly. Refer to Door Lock Switch Replacement . Is the replacement complete? | -- | -- | |
6 |
Is the replacement complete? | -- | -- | |
7 | Check the LH door unlock switch circuit for an intermittent malfunction. Refer to Diagnostic Aids. Was a problem found and repaired? | -- | ||
8 |
Does DTC B2238 set as history? | -- | System OK | |
9 |
Is the repair complete? | -- | -- |
