GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The mobility seat module monitors an input from a hall effect sensor in the rotation motor while the seat is being rotated in or out. The hall effect is a 12-volt 3-wire sensor and the signal circuit is referenced from battery voltage within the module.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 034 Swivel Motor Hall Sensor Circuit Fault During Inward Rotation

Conditions for Running the DTC

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

Conditions for Setting the DTC

When rotating the seat to the forward facing position no hall effect sensor pulses are detected by the module.

Action Taken When the DTC Sets

While the fault is current the module will disable the object detection feature and the alarm will sound during rotation motor operation.

Conditions for Clearing the DTC

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

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

Go to Step 3

3

Does the seat rotate to the forward facing position?

Go to Step 4

Go to Step 7

4

  1. Disconnect the swivel motor pigtail connector.
  2. Using a DMM measure the voltage at the hall effect sensor supply circuit terminal in the harness connector.

Is battery voltage present?

Go to Step 5

Go to Step 8

5

Measure the voltage between the hall effect sensor supply circuit terminal and the ground circuit terminal in the harness connector.

Is battery voltage present?

Go to Step 6

Go to Step 9

6

Measure the voltage at the hall effect sensor signal circuit terminal in the harness connector.

Is battery voltage present?

Go to Step 13

Go to Step 10

7

  1. Disconnect the swivel motor pigtail connector.
  2. Connect a test lamp between the motor control circuit terminals in the harness connector.
  3. Press the out switch on the remote.

Does the test lamp illuminate?

Go to Step 13

Go to Step 11

8

Test the hall effect sensor supply circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

9

Test the hall effect sensor ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

10

Test the hall effect sensor signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

11

Test the swivel motor control circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

12

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

Is the repair complete?

Go to Step 14

--

13

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

Is the repair complete?

Go to Step 14

--

14

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3