GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The mobility seat module uses inputs from 4 limit switches in order to determine the seat position. The limit switch signal circuits are referenced from battery voltage within the module. The limit switches will open or close the switch signal circuits to ground in order for the module to determine them to be active or inactive. The lift lower limit switch signal circuit is considered to be active when the circuit reference voltage is low or closed to ground by the switch.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 052 Lift Lower Limit Switch Remains Active After Start of Ascend

Conditions for Running the DTC

    • Battery voltage must be within 9-16 volts.
    • Seat ascend operation is attempted from the out of vehicle position.

Conditions for Setting the DTC

After seat ascend operation has been in progress for 1 second from the out of vehicle position the lift lower limit switch signal to the module remains low or active.

Action Taken When the DTC Sets

While the fault is current the module will allow the seat to be ascended to the in vehicle outward facing position and not allow the seat to descend to the out of vehicle position.

Conditions for Clearing the DTC

The DTC may be cleared by removing the main power supply or ground from the seat module.

Diagnostic Aids

Inspect the limit switch for any physical damage or obstructions to its mechanical operation which may cause the condition.

Step

Action

Yes

No

Schematic Reference: Passenger Seat Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you review the description and operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Seats

2

Verify the fault is present.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Disconnect the lift lower limit switch connector.
  2. Attempt to operate the seat to the out of vehicle position.

Does the seat descend to the out of vehicle position?

Go to Step 6

Go to Step 4

4

Test the lift lower limit switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 7

Go to Step 5

5

Replace the mobility seat control module. Refer to Sit-N-Lift Control Module Replacement .

Is the repair complete?

Go to Step 7

--

6

Replace the mobility seat base unit. Refer to Sit-N-Lift Seat Base Replacement .

Is the repair complete?

Go to Step 7

--

7

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3