Circuit Description
The LH seat switch circuit provides an input to the LH Seat Control Module (SCM) when the seat frontswitch is pressed UP. This input allows the SCM to detect a seat frontUP request. The SCM provides a signal, which is pulled up to system battery voltage through a pull-up resistor, and a ground to the seat frontup switch. When the seat frontup switch is pressed the signal is pulled low within the SCM. When the SCM detects the transition from high to low it will command the seat frontto move in the UP direction. When the switch is released it will command the seat frontto stop.
Conditions for Setting the DTC
The seat frontup switch input, to the SCM, is active (low) for more than 20 seconds.
Action Taken When the DTC Sets
| • | Stores a history DTC B2172 in the SCM 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. |
| • | The operation/function of the seat frontup switch is disabled. |
Conditions for Clearing the DTC
| • | The seat frontup switch input, to the SCM, is inactive (high) for less than 20 seconds. |
| • | Using a scan tool. |
Diagnostic Aids
| • | The following conditions may cause an intermittent malfunction: |
| - | There is an intermittent short to ground in CKT 1520. |
| - | The seat frontup switch is shorted to ground internally or is sticking. |
| - | The seat frontup switch was pressed for longer than 20 seconds. |
| • | If CKT 1520 is shorted to ground or the seat frontup switch is stuck closed, the seat will remain in the up position at all times. |
| • | Using a scan tool, select SCM inputs and monitor the seat frontup switch status. If the scan tool displays ACTIVE, disconnect the seat frontup switch and check if the seat status changes to INACTIVE. If the status changed, then replace the LH seat switch. If the status did not change, then check CKT 1520 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 |
| • | Activate the seat frontup switch numerous times while monitoring the status on the scan tool to see if it sticks intermittently. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Is there any mechical binding or obstruction? | |||
2 |
Is resistance within specified range? | <5ohms | ||
3 | Replace the Seat Control Module (SCM). Is the repair complete? | Recheck the System Operation | ||
4 |
Is the resistance within specified range? | <5ohms | ||
5 | Repair the open in CKT 1798 or CKT 1520 between the left seat switch and the Seat Control Module (SCM). Is the repair complete? | Recheck the System Operation | ||
6 | Replace the left seat switch. Is the repair complete? | Recheck the System Operation |
