GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the BCM System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System in Body Control System

2

Was the Audible Warnings System Check performed?

--

Go to Step 3

Go to Diagnostic System Check - Audible Warnings

3

  1. Insert the key in the ignition.
  2. Turn the ignition switch to the RUN position.
  3. Using a scan tool, enter BCM Data List INPUT 2.
  4. Monitor the left turn signal and the right turn signal.
  5. Move the turn signal switch to the LEFT and the RIGHT positions.

Does the scan tool alternate between ON and OFF for both parameters in relation to the turn signal switch position?

--

Go to Step 4

Go to Step 8

4

  1. Drive the vehicle with the scan tool installed.
  2. Enter BCM Data List DATA.
  3. Monitor the vehicle speed.

Is the vehicle speed displayed for the vehicle in motion?

--

Go to Step 5

Go to Step 10

5

Inspect the connections at the BCM. Refer to Intermittents and Poor Connections Diagnosis

Are the connections in need of repair?

--

Go to Step 6

Go to Step 7

6

Repair the connections at the BCM as necessary. Refer to Connector Repairs

Is the repair complete?

--

Go to Diagnostic System Check - Audible Warnings

--

7

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

Is the repair complete?

--

Go to Diagnostic System Check - Audible Warnings

--

8

  1. Using a J 39200 digital multimeter (DMM), backprobe the BCM connector C1 terminal B6 (left turn signal) and terminal B7 (right turn signal) to ground.
  2. Measure the voltage.
  3. Select the 40 Volt Range.
  4. Turn the ignition switch to the RUN position.
  5. Operate the turn signal switch.
  6. With the turn signals operating, push the MIN/MAX button 4 times.
  7. Avg. is displayed at the top of the meter.

Is approximately 1/2 battery voltage displayed on both terminals?

--

Go to Step 5

Go to Step 9

9

Repair the open or the high resistance between SP204 and BCM connector C1 CKT 1414 or CKT 1415 as necessary. Refer to Wiring Repairs

Is the repair complete?

--

Go to Diagnostic System Check - Audible Warnings

--

10

Repair the open or the high resistance in CKT 817 between BCM connector C2 terminal B1 and SP200 or PCM connector C2 terminal 16 (2.2L w/o cruise control) or VCM connector C4 terminal 3 (4.3L w/ cruise control). Refer to Wiring Repairs

Is the repair complete?

--

Go to Diagnostic System Check - Audible Warnings

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