GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 Century 🢒 Restraints 🢒 SIR 🢒 DTC B2818

Circuit Description

The body control module (BCM) monitors a signal circuit from the instrument panel 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 to turn off the LOW TIRE indicator.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2818 Tire Pressure

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.

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 Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
  1. Turn ON the ignition, with the engine OFF.
  2. 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 body control module (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 Control Module References in Computer/Integrating Systems for replacement, setup and programming.

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, Gages, and Console.

Did you complete the replacement?

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.

Does DTC 2818 reset?

Go to Step 2

System OK