GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2007 🢒 DTS 🢒 Steering 🢒 Steering Wheel and Column 🢒 DTC B2870

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B2870 01: Tilt Up Switch Circuit Short to Battery

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Steering Column Tilt Up Switch Signal

1

1

B2870

--

Steering Column Tilt Down Switch Signal

1

1

B2875

--

Steering Column Telescope Reverse Switch Signal

2

2

B2855

--

Steering Column Telescope Forward Switch Signal

2

2

B2850

--

1. Tilt Malfunction

2. Telescope Malfunction

Circuit Description

The memory seat module (MSM) receives voltage inputs from the tilt/telescope switch based on the position of the switch. The MSM then supplies battery voltage and a ground to the tilt or telescope motor control circuits depending on which direction of movement is requested.

Conditions for Running the DTC

The ignition ON.

Conditions for Setting the DTC

The MSM detects a tilt up switch input for more than 30 consecutive seconds after up movement of the motor has stopped.

Action Taken When the DTC Sets
    • The tilt motor 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    • A current DTC will clear when the failed switch input is no longer active.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 tilt switch may cause this DTC to set.

Reference Information

Schematic Reference

Tilt/Telescoping Steering Column Schematics

Connector End View Reference

Steering Wheel and Column Connector End Views

Description and Operation

Steering Wheel and Column Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Ignition ON, view the scan tool Tilt Up Switch parameter while cycling the tilt/telescope switch between the neutral and TILT UP position. The parameter should change between Active and Inactive.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the tilt/telescope switch.
  2. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 4 and ground.
    3. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Verify the scan tool Tilt Up Switch parameter is Inactive.
    4. ⇒If not the specified value, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the MSM.
  4. Install a 3A fused jumper wire between the signal circuit terminal 5 and the B+ circuit terminal 4. Verify the scan tool Tilt Up Switch parameter is Active.
    5. ⇒If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
  5. If all circuit test normal, test or replace the tilt/telescope switch.

Component Testing

Tilt/Telescope Switch

  1. Ignition OFF, disconnect the harness connector at the tilt/telescope switch.
  2. Test for infinite resistance between the following terminals with the switch in the neutral position:
    3. • B+ terminal 4 and signal terminal 5
    • B+ terminal 4 and signal terminal 1
    • B+ terminal 4 and signal terminal 2
    • B+ terminal 4 and signal terminal 3
    ⇒If less than the specified range, replace the tilt/telescope switch.
  3. Test for less than 1 ohm or resistance between the B+ terminal 4 and the signal terminal 5 with the switch in the TILT UP position.
    4. ⇒If greater than the specified range, replace the tilt/telescope switch.
  4. Test for less than 1 ohm or resistance between the B+ terminal 4 and the signal terminal 1 with the switch in the TILT DOWN position.
    5. ⇒If greater than the specified range, replace the tilt/telescope switch.
  5. Test for less than 1 ohm or resistance between the B+ terminal 4 and the signal terminal 2 with the switch in the TELESCOPE OUT position.
    6. ⇒If greater than the specified range, replace the tilt/telescope switch.
  6. Test for less than 1 ohm or resistance between the B+ terminal 4 and the signal terminal 3 with the switch in the TELESCOPE IN position.
    7. ⇒If greater than the specified range, replace the tilt/telescope switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Telescope Actuator Switch Replacement
    •  Control Module References for MSM replacement, setup, and programming