GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2000 🢒 S/T Isuzu - 4WD 🢒 DTC 🢒 DTC B2957 Security System Sensor Data Circuit Low

Object Number: 573177 Size: LF
Theft Deterrent System Components
Theft Deterrent System Schematics
Theft Deterrent System Schematic Icons

Circuit Description

The body control module (BCM) will read an analog voltage form the Passlock™ sensor. Based on an internal reference, the BCM will determine if the measured voltage is in one of the following conditions:

    • Open
    • Shorted to ground
    • A valid code
    • A tamper code

There are 10 possible valid code combination. The BCM will only recognize the last learned valid code.

Conditions for Setting the DTC
    • The ignition switch is ON.
    • The BCM signal input is less than 0.4 volt for 1 second after turning the ignition switch to the CRANK position.

Action Taken When the DTC Sets
    • The vehicle will not start if the fault occurs before you start the vehicle. The security indicator will flash for 10 minutes then turn ON steady.
    • If the vehicle is running when the fault occurs, the BCM will be in the fail enable mode allowing the vehicle to start and run. The security indicator will be ON.

Conditions for Clearing the DTC
    • The DTC will clear once the ignition cycle has occurred without the fault recurring.
    • The BCM history codes will clear once 100 concurrent ignition cycles occur without the fault recurring.
    • Using a scan tool.

Diagnostic Aids
    • When replacing the Passlock™ sensor, all of the following components are included as a replacement part and must be replaced:
       - The lock
       - The sensor
       - The filter
       - The harness
    • Use a scan tool in order to inspect the Passlock™ data voltage and the Passlock™ code.
    • Perform a visual inspection of the wiring and the connectors.
    • Following a repair the tamper timer needs 10 minutes in order to expire.

Test Description

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

  1. Tests for proper operation of the circuit in the high voltage range.

    2.

  2. Tests for a short to ground in the Passlock™ sensor signal circuit.

Step

Action

Value(s)

Yes

No

1

Did you perform the Theft Deterrent (VTD) Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2
  1. Install a scan tool.

    2. Important: Do not start the vehicle.

  2. Momentarily rotate the ignition switch to CRANK.
  3. Release the ignition switch to ON.
  4. With a scan tool, observe the Passlock™ data voltage in the Body Control Module Security Data list.

Does the scan tool indicate that the Passlock™ data voltage is within the specified range?

0.4-4.9 V

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the Passlock ™ sensor connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Passlock™ data voltage in the Body Control Module Security Data list.

Does the scan tool indicate that the Passlock™ data voltage is greater than the specified value?

4.9 V

Go to Step 7

Go to Step 4

4

Test the Passlock™ sensor signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 5

5

Inspect for poor connections at the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 6

6

Important: Perform the set up procedure for the body control module .

Replace the body control module. Refer to Body Control Module Replacement in Body Control Systems.

Did you complete the replacement?

--

Go to Step 10

--

7

Inspect for poor connections at the Passlock ™ sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

8

Replace the Passlock™ sensor in the electronic column lock module assembly. Use the appropriate procedure from the following list:

    • Tilt Wheel
       - With column shift
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle
       - With floor shift
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle
    • Standard Wheel
       - With column shift
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle
       - With floor shift
             1. Disassemble Electronic Column Lock Module - Disassemble - Off Vehicle
             2. Assemble Electronic Column Lock Module - Assemble - Off Vehicle

Did you complete the replacement?

--

Go to Step 9

--

9

Perform one of the following Passlock™ learn procedures:

    •  PASSLOCK Reprogramming Seed and Key (10 minutes).
    •  PASSLOCK Reprogramming Auto Learn (30 minutes).

Is the repair complete?

--

Go to Step 10

--

10
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition
  3. Turn ON the ignition, with the engine OFF.
  4. Select the body control module display DTCs function on the scan tool.

Does the DTC reset?

--

Go to Step 3

System OK