B2112 Lumbar Up Switch Failed (with AM3)

Diagnostic Trouble Code Chart:

Wiring Schematic:

CIRCUIT DESCRIPTION
The Memory Seat Module (MSM) receives an input from the LH lumbar switch through the LH lumbar massage module when the up switch is actuated. When the lumbar switch is operated in the up direction, battery positive voltage (B+) is supplied to the MSM lumbar up input via CKT 387 (RED). The MSM recognizes the input and moves the lumbar support in the up direction.

CONDITIONS FOR SETTING THE DTC
^ When the lumbar up switch is active for 30 seconds after motion has ceased, the switch will be considered shorted and the DTC will set.
^ If the lumbar vertical position sensor DTC B2120 is current and the lumbar up switch is active for 30 seconds the switch will be considered shorted and the DTC will set.
^ DTC B2112 will set only if DTC B1982 MSM or DTC B1983 MSM is not current.

ACTION TAKEN WHEN THE DTC SETS
^ The MSM will not move the lumbar support in the up direction.
^ The MSM will continue to respond to valid inputs from the other manual switches.
^ All memory recall function commands will be ignored for all directions.

CONDITIONS FOR CLEARING THE DTC
^ The MSM sees that the lumbar up switch is no longer active.
^ Use the On-Boards clearing DTCs feature.
^ Use a scan tool.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
1. Perform the entire Power Seat Systems Diagnostic System Check before continuing with the diagnosis of this DTC.
2. Determines whether there is a stuck switch in the LH lumbar switch. DTC B2112 will set again if there is a short in the wiring or if there is an internal lumbar massage module problem. DTC B2112 will not set again if there is a stuck switch because the switch has been disconnected from the LH lumbar massage module input.
3. Determines whether there is an internal problem with the LH lumbar massage module or if there is a short to ground in the input wiring to the LH lumbar massage module or to the MSM.
11. Clear all DTCs after the repair procedure is complete.