GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B1424: Device 1 Voltage Low

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+

B1424 00

B1424 00

--

--

Ground

--

B1424 00

--

--

Circuit/System Description

The theft deterrent module (TDM) monitors the battery positive (B+) circuit. If the voltage at the TDM is between 6 and 9 V, and the voltage being reported by the serial data message is greater than 9 V, DTC B1424 will set.

Conditions for Running the DTC

    • The Ignition is in Accessory or RUN.
    • The diagnostic runs every 100  milliseconds.

Conditions for Setting the DTC

    • Voltage at the B+ circuit is between 6 and 9 V.
    • Reported battery voltage received via serial data is valid and is greater than 9 V.
    • The above conditions have been met for 2 seconds.

Action Taken When the DTC Sets

Security Indicator turns ON.

Conditions for Clearing the DTC

    • A current DTC clears when the battery voltage at the TDM is greater than 9 V, or if the reported voltage by serial data is less than 9 V.
    • A history DTC clears after 100 ignition cycles, if no failures are reported by the diagnostic.

Diagnostic Aids

A low voltage DTC in multiple modules indicates a concern in the charging system.

Reference Information

Schematic Reference

Immobilizer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Immobilizer Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Engine running measure and record the voltage at the battery terminals. Verify that the battery voltage is 12.6-15.5 V.

If the battery voltage is not within the specified range, refer to Charging System Test.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the theft deterrent module (TDM).
  2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 Ω between the ground circuit terminal 3 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON , verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
  5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  6. If the circuits test normal, replace the TDM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for TDM replacement, set up, and programming