GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2004 🢒 Regal 🢒 Suspension 🢒 Tire Pressure Monitoring 🢒 DTC B2818

Circuit Description

The Body Control Module (BCM) monitors a signal circuit from the Instrument Panel (IP) Fuse Block reset switch. When a ground signal is detected on this circuit, the BCM sends a message via a class 2 serial data circuit to the Instrument Panel Cluster (IPC) to turn off the LOW TIRE indicator.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The BCM detects a ground signal from the reset switch signal circuit for more than 15 seconds.

Action Taken When the DTC Sets
    • A DTC B2818 is stored in memory.
    • The BCM ignores the reset switch signal circuit input for the remainder of the ignition cycle.

Conditions for Clearing the DTC
    • A current DTC will clear when the malfunction is no longer present.
    • A history DTC will clear after 100 malfunction free ignition cycles.
    • Using a scan tool

Test Description

The number below refer to the step number on the diagnostic table.

  1. Tests if the malfunction is in the BCM or in the reset switch signal circuit.

Step

Action

Yes

No

Schematic Reference : Tire Pressure Monitoring System Schematics

1

Did you perform the Tire Pressure Monitor Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Tire Pressure Monitoring

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the TIM Reset Switch data parameter in the TIM data list.

Does the scan tool display Released?

Go to Step 3

Go to Step 4

3
  1. Depress the RESET switch.
  2. With the scan tool, observe the TIM Reset Switch data parameter.

Does the TIM Reset Switch data parameter change states?

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

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the BCM harness connector.
  3. disconnect the Low Tire Pressure Reset Switch Signal circuit from the BCM harness connector.
  4. Reconnect the BCM harness connector to the BCM.
  5. Turn ON the ignition, with the engine OFF.
  6. With a scan tool, observe the TIM Reset Switch data parameter.

Does the scan tool display Released?

Go to Step 5

Go to Step 6

5

Test the signal circuit of the RESET switch for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 7

6

Replace the BCM. Refer to Body Control Module Replacement in Body Control Systems.

Did you complete the replacement?

Go to Step 8

--

7

Replace the RESET switch. Refer to Instrument Panel Electrical Center or Junction Block Replacement in Instrument Panel, Gauges and Console.

Did you complete the replacement?

Go to Step 8

--

8
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK