GM Service Manual Online
For 1990-2009 cars only

Object Number: 281486  Size: MF
Theft Deterrent System Components
Cell 133: Fuel Tank Module, Instrument Cluster and Passlock Cylinder
Handling ESD Sensitive Parts Notice

Circuit Description

This circuit supplies the Passlockā„¢ data to the body control module (BCM) from the Passlockā„¢ sensor, CKT 1836.

Conditions for Setting the DTC

All of the following conditions must be met:

    • CKT 1836 is open or shorted to B+.
    • Ignition 0 is active.

Action Taken When the DTC Sets

    • The security indicator illuminates.
    • The BCM stores the DTC B2958 in the BCM memory.
    • The vehicle will start, then stall.

Conditions for Clearing the DTC

    • The BCM goes to sleep and reinitializes with the fault cleared.
    • All of the BCM history codes will be cleared after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.
    • Use a scan tool.

Diagnostic Aids

    • If the DTC is a history DTC, the problem may be intermittent. Perform the test shown while wiggling the wiring and connectors. This will cause the malfunction to appear.
    • If the malfunction occurred while driving the vehicle will start on subsequent key cycles.
    • Inspect for a poor connection at the Passlock® sensor and BCM.

Test Description

The numbers below refer to the numbers on the diagnostic table.

  1. This step determines if a short to the battery exists in CKT 1836 between the Body Control Module (BCM) and the Passlock® sensor.

Step

Action

Value(s)

Yes

No

Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.

1

Was the Theft Deterrent System diagnostic system check performed?

--

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2

  1. Disconnect the Body Control Module (BCM) connector C2
  2. Disconnect the Passlock® sensor connector.
  3. Use the J 39200 in order to measure the voltage in CKT 1836 between the Passlock® connector terminal A and ground.

Is the measured voltage greater than the specified value?

0 V

Go to Step 3

Go to Step 4

3

Repair the short to voltage in CKT 1836 between the Passlock® connector terminal A and the BCM connector C2 terminal B6. Refer to Wiring Repairs in Wiring Systems

Is the repair complete?

--

Go to Step 13

--

4

Use the J 39200 in order to measure the resistance in CKT 1836 between the BCM connector C2 terminal B6 and the Passlock® connector terminal A.

Is the measured resistance within the specified range?

0-2 ohms

Go to Step 6

Go to Step 5

5

Repair the open or repair the high resistance in CKT 1836 between the BCM connector C2 terminal B6 and the Passlock® connector terminal A.

Is the repair complete?

--

Go to Step 13

--

6

Inspect for a poor connection at the BCM connector C2 terminal B6.

Was a poor connection found?

--

Go to Step 7

Go to Step 8

7

Repair the poor connection at the BCM connector C2 terminal B6. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 13

--

8

Inspect for a poor connection at the Passlock® sensor connector terminal A.

Was a poor connection found?

--

Go to Step 10

Go to Step 11

9

  1. Disconnect connector C2 from the BCM.
  2. Using a J 39200 set on DC voltage, backprobe CKT 1836 at terminal B6 of connector 2.

Is the voltage greater than the specified value?

6 V

Go to Step 11

Go to Step 12

10

Repair the poor connection at the Passlock® sensor connector terminal A. Refer to Wiring Repairs in Wiring Systems

Is the repair complete?

--

Go to Step 13

--

11

  1. Replace the Passlock® sensor.
  2. Reconnect the BCM.

Is the repair complete?

--

Go to Step 13

--

12

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

Is the repair complete?

--

Go to Step 13

--

13

Clear the DTCs from the memory.

Are the DTCs cleared from the memory?

--

Go to Diagnostic System Check - Theft Deterrent

--