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 swivel in limit switch signal circuit is considered to be active when the circuit reference voltage is high or open to ground by the switch.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 031 Swivel In Limit Switch Active at Start of Rotation In

Conditions for Running the DTC

    • Battery voltage must be within 9-16 volts.
    • Seat rotation in operation is attempted from the outward facing position.

Conditions for Setting the DTC

When the seat is operated to the inward facing position from the outward facing position the swivel in limit switch signal to the module is high or active.

Action Taken When the DTC Sets

While the fault is current the module will allow the seat to be rotated to the forward facing position and not allow outward rotation.

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 Power Seats System Description and Operation

2

Verify the fault is present.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Disconnect the swivel in limit switch connector.
  2. Connect a jumper wire to the swivel in limit switch signal circuit terminal in the harness connector.
  3. While attempting to operate the seat to the facing outward position connect the jumper wire to ground.

Does the seat rotate to the outward facing position?

Go to Step 5

Go to Step 4

4

Test the swivel in limit switch signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 6

5

Test the swivel in limit switch ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 8

6

Inspect for poor connections at the mobility seat module harness connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

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

Is the repair complete?

Go to Step 9

--

8

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

Is the repair complete?

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3