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For 1990-2009 cars only

DTC P1574 ECM w/L61

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 P1574 : Stop Lamp Switch Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open or High Resistance

Short to Voltage

Signal Performance

Stop Lamp Switch Signal

P1574

P1574

P1574

--

Circuit/System Description

The stoplamp switch is used to sense the action of the driver application of the brake pedal. The stoplamp switch will apply battery voltage to the park/stoplamp signal voltage supply circuit to illuminate the stop lamps and the center high mounted stop lamp (CHMSL). The stoplamp switch also sends a signal to the engine control module (ECM) as well to indicate the application of the brake pedal.

Conditions for Running the DTC

    • The ignition is ON.
    • Battery voltage is greater than 11.5 volts.

Conditions for Setting the DTC

The ECM detects a short to ground, short to voltage, or open on the stop lamp switch signal circuit when the brakes are applied.

Action Taken When the DTC Sets

    • The ECM stores the DTC to memory.
    • The ECM will record the operating conditions at the time the diagnostic failed. The ECM stores this information in Failure Records.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs command.
    • A history DTC will clear once 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

  1. Perform the stoplamp switch adjustment, refer to Stop Lamp Switch Adjustment , clear all DTCs, and operate the vehicle within the Conditions for Running the DTC.
  2. If DTC P1574 resets as current, test the stop lamp switch signal circuit for a short to ground, short to voltage, or open.
  3. If circuits test OK, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Module References for ECM replacement, setup, and programming
    •  Stop Lamp Switch Adjustment

DTC P1574 PCM w/L66

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 P1574 : Stop Lamp Switch Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open or High Resistance

Short to Voltage

Signal Performance

Stop Lamp Switch Signal

P1574

P1574

P1574

--

Circuit/System Description

The stoplamp switch is used to sense the action of the driver application of the brake pedal. The stoplamp switch will apply battery voltage to the park/stoplamp signal voltage supply circuit to illuminate the stop lamps and the center high mounted stop lamp (CHMSL). The stoplamp switch also sends a signal to the powertrain control module (PCM) as well to indicate the application of the brake pedal.

Conditions for Running the DTC

    • The ignition is ON.
    • Battery voltage is greater than 11.5 volts.

Conditions for Setting the DTC

The PCM detects a short to ground, short to voltage, or open on the stop lamp switch signal circuit when the brakes are applied.

Action Taken When the DTC Sets

    • The PCM stores the DTC to memory.
    • The PCM will record the operating conditions at the time the diagnostic failed. The PCM stores this information in Failure Records.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs command.
    • A history DTC will clear once 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

  1. Perform the stoplamp switch adjustment, refer to Stop Lamp Switch Adjustment , clear all DTCs, and operate the vehicle within the Conditions for Running the DTC.
  2. If DTC P1574 resets as current, test the stop lamp switch signal circuit for a short to ground, short to voltage, or open.
  3. If circuits test OK, replace the PCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Module References for PCM replacement, setup, and programming
    •  Stop Lamp Switch Adjustment

DTC P1574 TCM w/L61 w/MN5

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 P1574 : Stop Lamp Switch Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open or High Resistance

Short to Voltage

Signal Performance

Stop Lamp Switch Signal

P1574

P1574

P1574

--

Circuit/System Description

The stoplamp switch is used to sense the action of the driver application of the brake pedal. The stoplamp switch will apply battery voltage to the park/stoplamp signal voltage supply circuit to illuminate the stop lamps and the center high mounted stop lamp (CHMSL). The stoplamp switch also sends a signal to the Transmission control module (TCM) as well to indicate the application of the brake pedal.

Conditions for Running the DTC

    • The ignition is ON.
    • Battery voltage is greater than 11.5 volts.

Conditions for Setting the DTC

The TCM detects a short to ground, short to voltage, or open on the stop lamp switch signal circuit when the brakes are applied.

Action Taken When the DTC Sets

    • The TCM stores the DTC to memory.
    • The TCM will record the operating conditions at the time the diagnostic failed. The TCM stores this information in Failure Records.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs command.
    • A history DTC will clear once 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

  1. Perform the stoplamp switch adjustment, refer to Stop Lamp Switch Adjustment , clear all DTCs, and operate the vehicle within the Conditions for Running the DTC.
  2. If DTC P1574 resets as current, test the stop lamp switch signal circuit for a short to ground, short to voltage, or open.
  3. If circuits test OK, replace the TCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Module References for TCM replacement, setup, and programming
    •  Stop Lamp Switch Adjustment