GM Service Manual Online
For 1990-2009 cars only

Circuit Description

Memory seat module (MSM) receives ground inputs from contacts inside the tilt/telescope switch. The memory seat module then supplies battery voltage to the tilt motor up or down circuit or the telescope motor in or out circuit depending on which direction of movement is requested. Both motors are reversible and the voltage for any circuit is used to accomplish movement in opposite directions.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC 2853 Telescope Forward Switch Circuit High
    • DTC 2858 Telescope Rearward Switch Circuit High
    • DTC 2873 Tilt Up Switch Circuit High
    • DTC 2878 Tilt Down Switch Circuit High

Conditions for Running the DTC

The memory seat module is ON.

Conditions for Setting the DTC

The memory seat module detects a switch input for more than 30 consecutive seconds after movement of the motor in the requested direction has stopped.

Action Taken When the DTC Sets

    • The motor that is being driven by the failed switch will be deactivated.
    •  Memory recall functions will be disabled.

Conditions for Clearing the DTC

    • A current DTC will clear when the failed switch input is no longer active
    • A history DTC will clear after 100 ignition cycles.

Diagnostic Aids

An intermittently stuck switch can cause this DTC to set. Refer to Testing for Intermitten Conditions and Poor Connections.

DTC B2853, B2858, B2873, or B2878

Step

Action

Yes

No

Schematic Reference: Tilt/Telescoping Steering Column Schematics

Connector End View Reference: Steering Wheel and Column Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Retrieve DTCs with the scan tool.

Is DTC B2853, B2858, B2873 or B2878 displayed as current?

Go to Step 3

Go to Diagnostic Aids

3

  1. Turn OFF the ignition.
  2. Disconnect the tilt/telescoping switch harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Retrieve DTCs with the scan tool

Is DTC B2853, B2858, B2873 or B2878 displayed as current?

Go to Step 4

Go to Step 5

4

Inspect for poor connections at the harness connector of the tilt/telescoping steering column switch. Refer to Testing for Intermittent Conditions and Poor Connections.

Did you find and correct the condition?

Go to Step 7

Go to Step 6

5

Replace the tilt/telescopic steering column switch.

Did you complete the replacement?

Go to Step 7

--

6

Important: Perform the set up procedure for the memory seat module.

Replace the memory seat module (MSM). Refer to Front Seat Control Module Replacement.

Did yo complete the replacement?

Go to Step 7

--

7

Calibrate the Steering Column. Refer to Telescoping Steering Column Calibration.

Did you complete the operation?

Go to Step 8

--

8

  1. Clear the DTCs with the scan tool.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
  3. Does the DTC reset?

Go to Step 2

System OK