For 1990-2009 cars

### 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 P2533: Ignition 1 Switch Circuit
DTC P2533 06: Ignition 1 Switch Circuit Short to Ground or Open

### Circuit/System Description

The engine control module (ECM) uses the ignition 1 voltage circuit to monitor system voltage. Voltage that is out of range will cause damage to components and incorrect input readings.

### Conditions for Running the DTC

• | The ignition is ON.

• | The DTC runs once per ignition cycle once the above condition is met.

### Conditions for Setting the DTC

The ECM detects an open or a short to ground on the Ignition 1 Voltage Circuit.

### Action Taken When the DTC Sets

DTC P2533 is a Type B DTC.

### Conditions for Clearing the DTC

DTC P2533 is a Type B DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Ignition ON, observe the scan tool ignition 1 data parameter. The parameter should indicate the circuit is active.
2. Observe the DTC information with a scan tool. DTC P2533 should not set.
3. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

### Circuit/System Testing

1. Ignition OFF, disconnect the ECM harness connector X1.
2. Ignition ON, measure the voltage on the ignition 1 voltage circuit terminal X1-28. The DMM should display battery voltage.

⇒ | If less than the specified range, test the circuit for an open or a short to ground.

3. Verify a test lamp illuminates between the ignition 1 voltage circuit terminal X1-28 and ground.

⇒ | If the test lamp does not illuminate, repair the ignition 1 circuit for a high resistance.

4. If the circuit/connections test normal replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming