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 provide 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
DTC P0261: Injector 1 Control Circuit Low Voltage
DTC P0262: Injector 1 Control Circuit High Voltage
DTC P0264: Injector 2 Control Circuit Low Voltage
DTC P0265: Injector 2 Control Circuit High Voltage
DTC P0267: Injector 3 Control Circuit Low Voltage
DTC P0268: Injector 3 Control Circuit High Voltage
DTC P0270: Injector 4 Control Circuit Low Voltage
DTC P0271: Injector 4 Control Circuit High Voltage

### 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 | P0261 | P0201 | P0262 | --
Injector 2 Control Circuit | P0264 | P0202 | P0265 | --
Injector 3 Control Circuit | P0267 | P0203 | P0268 | --
Injector 4 Control Circuit | P0270 | P0204 | P0271 | --

### Circuit/System Description

The control module enables the appropriate fuel injector on the intake stroke for each cylinder. Ignition voltage is supplied directly to the fuel injectors. The control module controls each fuel injector by grounding the control circuit with a solid state device called a driver. The control module monitors the status of each driver.

### Conditions for Running the DTC

• | The ignition is ON.

• | The DTCs run continuously once the above condition is met.

### Conditions for Setting the DTC

#### P0201, P0202, P0203, or P0204

The ECM detects the injector control circuit is open.

#### P0261, P0264, P0267, or P0270

The ECM detects the injector control circuit is shorted to ground.

#### P0262, P0265, P0268, or P0271

The ECM detects the injector control circuit is shorted to voltage.

### Action Taken When the DTC Sets

DTCs P0201, P0202, P0203, P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0201, P0202, P0203, P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271 are Type B DTCs.

### Diagnostic Aids

• | Performing the fuel injector coil test may help isolate an intermittent condition. Refer to Fuel Injector Solenoid Coil Test .

• | If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The ODM information is in the output driver module (ODM) data list.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls Connector End Views

#### 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

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Observe the scan tool Misfire Current Counter parameters. The Misfire Current Counters should not be incrementing.
2. Engine operating, observe the scan tool DTC information parameter. DTCs P0201, P0202, P0203, P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, and P0271 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 Data List.

### Circuit/System Testing

1. Ignition OFF, and the MAIN fuse removed, disconnect the harness connector at the appropriate fuel injector.
2. Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit 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. Install the MAIN fuse. Ignition OFF, connect a J 34730-405 between the control circuit and the ignition 1 voltage circuit. Engine idling, 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.

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

### Component Testing

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

Test for 12-16 ohms of resistance between the terminals of the fuel injector.

⇒ | If the resistance is 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