Circuit Description
The LH Door Control Module (LDCM) provides an illuminated output control for the LH door switch assembly. This allows the LDCM to illuminate the LH door switch back lighting, memory indicators, and mirror select indicators. The LDCM provides a single power supply for all illuminated light functions. The LDCM uses a Pulse-Width Modulation (PWM) ground output to control the dimming level to the LH door switch back lighting lamp. When the LDCM receives a message on the serial data line indicating that the park lamps or headlamps are ON, the LDCM will control the LH switch illumination by PWM-ing the ground. The LDCM also provides a ground output for the memory 1, memory 2, LH and RH mirror select switch indicators. The LDCM provides a ground output to each of these indicators allowing the LDCM to illuminate the applicable indicator based upon the select switch signal information. The LDCM monitors the amount of current draw on all of the illumination lamp control circuits. If the current draw is not within the acceptable range, a malfunction is present and a DTC will set.
Conditions for Setting the DTC
| • | The LDCM detects a high current (short to ground) condition in any one of the following LH door switch control circuits: |
| - | RH or LH mirror indicator |
| - | Memory 1 indicator |
| - | Memory 2 indicator |
| - | LH door switch Illumination lamp |
| • | Condition must be present for 20 ms. |
Action Taken When the DTC Sets
| • | Stores a history DTC B2278 in the LDCM memory. |
| • | The LDCM will disable the malfunctioning indicator. |
| • | 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 high current (short to ground) condition in the applicable indicator/lamp control circuit for longer than 20 ms. |
| • | 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 voltage or ground in the following LH door switch illumination or indicator control circuits: |
| • | LH door switch illumination lamp |
| • | Memory 1 select indicator |
| • | Memory 2 select indicator |
| • | LH mirror select indicator |
| • | RH mirror select indicator |
| - | The LH door switch indicator/lamp is shorted. |
| • | Using a scan tool, select LDCM Data and monitor the door switch pad illumination while rotating the interior light dimming switch. The switch illumination level varies based upon the dimming level information the LDCM receives on the serial data link. This checks if the LDCM is able to receive the correct dimming information from the serial data line. |
| • | 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 number(s) below refer to the step number(s) on the diagnostic table.
-
This tests if the LH door switch for an internal short to voltage or ground.
-
This tests the LH door switch illumination circuits for a short to voltage or ground.
Step | Action | Value(s) | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Power Door Systems Diagnostic System Check? | -- | Go to Step 2 | |||||||||||
Does the DTC reset? | -- | Go to Step 3 | Go to Step 5 | |||||||||||
Test the following LH door switch illumination control circuits for a short to ground or voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 4 | |||||||||||
4 | Replace the LH DCM. Refer to Door Control Module Replacement . Did you complete the replacement? | -- | Go to Step 6 | -- | ||||||||||
5 | Replace the LH door switch. Refer to Front Door Switch Replacement . Did you complete the replacement? | -- | Go to Step 6 | -- | ||||||||||
6 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
