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Makes 🢒 GMC_Truck 🢒 1999 🢒 Savana 🢒 Body and Accessories 🢒 Data Link Communications 🢒 DTC B0688 Security System Indicator Circuit High

DTC B0688 Security System Indicator Circuit High Domestic


Object Number: 381571 Size: LF
Theft Deterrent System Components
Theft Deterrent System Schematics Passlock
Cell 11: GAUGES Fuse
Cell 11: SECURITY STRG, PARK LPS, PWR WDO, WIPER, RADIO-I Fuses, R208
Cell 11: STOP, PWR AUX, CIG LTR, RADIO-B, HTD MIR, HAZARD Fuses
Instrument Cluster: Analog Schematics Domestic
Cell 11: GAUGES Fuse
Cell 11: STOP, PWR AUX, CIG LTR, RADIO-B, HTD MIR, HAZARD Fuses
Cell 14: G201
Cell 14: G103 (4.3L)
Theft Deterrent System Schematic Icons
Theft Deterrent System Schematic Icons
Theft Deterrent System Schematic Icons
Theft Deterrent System Schematic Icons

Circuit Description

The security indicator is a hardwired lamp that receives power form the gauges fuse 4 through CKT 39.

Conditions for Setting the DTC
    • The ignition switch is ON.
    • The Passlock module is unable to provide a complete path to ground for the security indicator due to a wiring fault or a defective Passlock module.

Action Taken When the DTC Sets
    • The ignition switch is ON.
    • The security indicator is commanded ON.
    • The Passlock module connector terminal B2 voltage is greater than 2.9 volts.
    • The security indicator may be on when the ignition switch is OFF if CKT 749 is shorted to battery power.

Conditions for Clearing the DTC
    • The DTC will clear after an ignition cycle has occurred without the fault.
    • The Passlock module history codes will be cleared after 100 ignition cycles with no current codes active.
    • Using a scan tool.

Diagnostic Aids
    • Perform a visual inspection of the wiring and the connectors.
    • Inspect the Passlock sensor harness for an intermittent or a short to battery. Refer to Intermittents and Poor Connections .

Test Description

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

  1. This step isolates the problem between the harness and the Passlock module.

    2.

  2. This step isolates the problem between the instrument cluster and the harness

Step

Action

Value(s)

Yes

No

1

Did you perform the VTD Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2
  1. Turn the ignition switch OFF.
  2. Disconnect the Passlock module connector.
  3. Remove the security indicator lamp. Refer to Instrument Cluster Replacement .
  4. Reconnect the cluster without the lamp.
  5. Turn the ignition switch ON.
  6. Use a J 39200 digital multimeter (DMM) in order to measure the voltage from the Passlock module connector terminal B2 to ground.

Is the voltage within the specified range?

9-16 volts

Go to Step 3

Go to  5

3
  1. Disconnect the instrument cluster connector. Refer to Instrument Cluster Replacement .
  2. Ensure that the ignition switch is still ON.
  3. Use a J 39200 in order to measure the voltage from the Passlock module connector terminal B2 to ground.

Is the voltage within the specified range?

9-16 volts

Go to Step 4

Go to Step 6

4

Repair the short to battery in CKT 749.

Is the repair complete?

--

Go to Diagnostic System Check - Theft Deterrent

--

5

Replace the Passlock module. Refer to Theft Deterrent Module Replacement .

Is the repair complete?

--

Go to Step 7

--

6

Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Diagnostic System Check - Theft Deterrent

--

7
  1. Reconnect all of the previously disconnected connectors and the components.
  2. Turn the ignition switch ON.
  3. Connect the scan tool.
  4. Clear the DTCs.
  5. Perform 1 of the following Passlock reprogramming procedures:

Is the repair complete?

--

Go to Diagnostic System Check - Theft Deterrent

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DTC B0688 Security System Indicator Circuit High Export


Object Number: 355702 Size: MF

Circuit Description

The Vehicle Immobilizer Module (VIM) controls the operation of the SECURITY indicator lamp by providing ground at the VIM terminal M. Lamp control is based upon signals received from the transmitter in the key fob and inputs from the following components:

    •  the VCM (Class 2 Data, terminal C and terminal D)
    • the ignition switch (Ignition 1, terminal J)
    • the brake pedal (Stop Lamps, terminal L)
    • the SECURITY indicator (SECURITY Indicator Control, terminal M)

Conditions for Setting the DTC

When the VIM is commanding the lamp on and the voltage measured at VIM terminal M is greater than 7 volts, DTC B0688 is set.

Conditions for Clearing the MIL/DTC
    • A history DTC will clear after 100 consecutive ignition cycles have occurred without a fault.
    • History and current DTCs can be cleared by using the Tech 2 scan tool.

Intermittent and Poor Connections

Most intermittent faults are caused by a faulty electrical connection or wiring, although a damaged VIM module can occasionally be at fault. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems for a detailed explanation of how to locate and repair intermittent conditions.

Test Description

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

  1. This test inspects for a short to voltage in the SECURITY indicator control circuit.

  2. This test inspects for a shorted indicator lamp.

  3. This test determines whether the malfunction is due to a short to voltage in the Instrument Panel Cluster circuitry or a malfunctioning Vehicle Immobilizer Module (VIM).

Step

Action

Value(s)

Yes

No

1

Was the On-Board Diagnostic (OBD) System Check performed?

Less than 1V

Go to Step 2

        in Engine Controls - 5.0, 5.7L
        in Engine Controls - 6.5L

2
  1. Turn the Ignition Switch to the OFF position.
  2. Disconnect the Instrument Panel Cluster.
  3. Disconnect the VIM.
  4. Turn the Ignition Switch to the RUN position.
  5. Measure the voltage on the VIM harness connector from the terminal M to the terminal N (ground).

Is the voltage less than 1V?

--

Go to Step 4

Go to Step 3

3
  1. Turn the Ignition Switch to the OFF position.
  2. Repair the short to voltage in CKT 749.
  3. Reconnect the Instrument Panel Cluster.
  4. Reconnect the VIM.
  5. Clear the DTCs.

Is the repair complete?

--
        in Engine Controls - 5.0, 5.7L
        in Engine Controls - 6.5L

--

4
  1. Turn the Ignition Switch to the OFF position.
  2. Remove the SECURITY indicator bulb.
  3. Inspect the SECURITY indicator bulb.

Is there a short in the SECURITY indicator bulb?

--

Go to Step 5

Go to Step 6

5
  1. Replace the SECURITY indicator bulb.
  2. Reconnect the Instrument Panel Cluster.
  3. Reconnect the VIM.
  4. Clear the DTCs.

Is the repair complete?

--
        in Engine Controls - 5.0, 5.7L
        in Engine Controls - 6.5L

--

6
  1. Reconnect the Instrument Panel Cluster without the SECURITY indicator bulb installed.
  2. Turn the Ignition Switch to the RUN position.
  3. Measure the voltager on the VIM harness connector from the terminal M to the terminal N (ground).

Is the voltage less than 1V?

Less than 1V

Go to Step 7

Go to Step 8

7
  1. Turn the Ignition Switch to the OFF position.
  2. Replace the VIM.
  3. Reconnect the Instrument Panel Cluster.

Is the repair complete?

--
        in Engine Controls - 5.0, 5.7L
        in Engine Controls - 6.5L

--

8
  1. Turn the Ignition Switch to the OFF position.
  2. Service the Instrument Panel Cluster.
  3. Reconnect the Instrument Panel Cluster.
  4. Reconnect the VIM.
  5. Clear the DTCs

Is the repair complete?

--
        in Engine Controls - 5.0, 5.7L
        in Engine Controls - 6.5L

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