GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Montana 🢒 Body and Accessories 🢒 Body Control System 🢒 Diagnostic System Check

Test Description

The number(s) below refer to the step number(s) on the diagnostic table:

  1. This step checks for proper operation of the fasten safety belt indicator.

    2.

  2. This step checks to see if the scan tool powers up.

    3.

  3. This step checks to see if the scan tool can communicate with the body control module (BCM).

    4.

  4. This step checks to see if there are any current or history diagnostic trouble codes (DTCs) present.

    5.

  5. This step checks to see if there are any communication DTCs (U-codes) present.

    6.

  6. This step checks to see if DTC B1000 (ECU Malfunction) is present.

Step

Action

Value(s)

Yes

No

1

  1. Note the seat belt indicator while turning ON the ignition.
  2. If the driver seat belt is buckled, the seat belt indicator will turn OFF.
  3. If the driver seat belt is unbuckled, the seat belt indicator will stay ON for approximately 20 seconds, then flash 55 times, and then turn OFF.

Does the seat belt indicator operate properly?

--

Go to Step 2

Go to Symptoms

2

Install a scan tool.

Does the scan tool power up?

--

Go to Step 3

Go to Scan Tool Does Not Power Up in Data Link Communications

3

Attempt to establish communications with the body control module (BCM).

Does the scan tool communicate with the BCM?

--

Go to Step 4

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

4

  1. Use the scan tool to request the BCM diagnostic trouble code (DTC) display.
  2. Record the displayed DTC(s) on the repair order, specifying as current or history.

Does the scan tool display any current or history DTCs?

--

Go to Step 5

System OK

5

Does the scan tool display and DTC's which begin with a "U"?

--

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

Go to Step 6

6

Does the scan tool display DTC B1000?

--

Go to DTC B1000 ECU Malfunction in Body Control System

Go to Diagnostic Trouble Code (DTC) List/Type