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 Descriptors

DTC P0201: Injector 1 Control Circuit
DTC P0202: Injector 2 Control Circuit
DTC P0203: Injector 3 Control Circuit
DTC P0204: Injector 4 Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Voltage | P0201, P0202, P0203, P0204 | P0201, P0202, P0203, P0204 | -- | --
Injector 1 Control Circuit | P0201 | P0201 | P0201 | --
Injector 2 Control Circuit | P0202 | P0202 | P0202 | --
Injector 3 Control Circuit | P0203 | P0203 | P0203 | --
Injector 4 Control Circuit | P0204 | P0204 | P0204 | --

### Circuit/System Description

The engine control module (ECM) enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied to the fuel injectors. The ECM controls each fuel injector by grounding the control circuit via a solid state device called a driver. The ECM monitors the status of each driver.

### Conditions for Running the DTC

• | The engine speed is greater than 700 RPM.

• | The ignition 1 voltage is greater than 9 volts.

• | The DTCs run continuously once the above conditions are met.

### Conditions for Setting the DTC

The ECM detects the injector control circuit is open, shorted to voltage, or shorted to ground for greater than 5 seconds.

### Action Taken When the DTC Sets

DTCs P0201, P0202, P0203, P0204 are Type A DTCs.

### Conditions for Clearing the DTC

DTCs P0201, P0202, P0203, P0204 are Type A DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Description and Operation

Fuel System Description

#### 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

Control Module References for scan tool information

#### Special Tools

J 34730-405 Injector Test Lamp

### Circuit/System Verification

1. Engine running, observe the DTC information with a scan tool. DTCs P0201, P0202, P0203, or P0204 should not set.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
2. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 1 and ground.

⇒ | If the test lamp does not illuminate, repair the ignition 1 voltage circuit for a short to ground or an open/high resistance. Replace the fuse if necessary.

3. Ignition OFF, connect a J 34730-405 between the control circuit terminal 2 and the ignition 1 voltage circuit terminal 1.
4. Engine running, the test lamp should flash.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If circuit tests normal, replace the ECM.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the fuel injector.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the fuel injector.

Note: The engine coolant temperature (ECT) sensor must be between 10-32°C (50-90°F) in order for an accurate measurement.

2. Test for 11-14 ohms of resistance between the ignition 1 voltage terminal 1 and the control terminal 2.

⇒ | If not within the specified range, replace the fuel injector.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Fuel Injection Fuel Rail Assembly Replacement

• | Control Module References for engine control module replacement, setup, and programming