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 P0201 00: Cylinder 1 Injector Control Circuit
DTC P0202 00: Cylinder 2 Injector Control Circuit
DTC P0203 00: Cylinder 3 Injector Control Circuit
DTC P0204 00: Cylinder 4 Injector Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition Voltage | P0689 00 | P0201 00**, P0202 00**, P0203 00**, P0204 00**, P0689 00* | -- | --
Injector 1 Control Circuit | P0201 00, P0300 00 | P0201 00, P0300 00 | P0201 00, P0300 00 | --
Injector 2 Control Circuit | P0202 00, P0300 00 | P0202 00, P0300 00 | P0202 00, P0300 00 | --
Injector 3 Control Circuit | P0203 00, P0300 00 | P0203 00, P0300 00 | P0203 00, P0300 00 | --
Injector 4 Control Circuit | P0204 00, P0300 00 | P0204 00, P0300 00 | P0204 00, P0300 00 | --
* Engine cranks but does not start. Open fuse, cranks no start ** If the condition is between the injector and the splice.

### Circuit/System Description

The control module enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver. The control module monitors the status of each driver. If the control module detects an incorrect voltage for the commanded state of the driver, a fuel injector control circuit DTC sets.

### Conditions for Running the DTC

• | The engine is running.

• | The battery voltage is greater than 9 V.

• | These DTCs run continuously when the above conditions are met

### Conditions for Setting the DTC

• | The control module detects an incorrect voltage on the fuel injector control circuit.

• | The above condition is met for 5 s

### Actions Taken When the DTC Sets

DTCs P0201 00, P0202 00, P0203 00, P0204 00 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0201 00, P0202 00, P0203 00, P0204 00, are Type B DTCs.

### Diagnostic Aids

• | The MIL indicator flashes when there is an engine misfire.

• | High resistance in the circuits of the injectors could set a misfire DTC without setting an injector DTC. Test the injector circuits of the affected cylinder(s) for a high resistance if you suspect a condition.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component 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

Control Module References for scan tool information

#### Special Tools

EL-34730-405 Injector Test Lamp

### Circuit/System Verification

Note: If you were sent here from DTC P0300 00-P0304 00 proceed to circuit/system testing.

1. Engine running, observe the DTC information with a scan tool. DTCs P0201 00, P0202 00, P0203 00, or P0204 00 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 Q17 Fuel Injector.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the appropriate Q17 Fuel Injector and replace the fuse.

3. Test for 2.5-3.5 V between the K20 Engine Control Module (ECM) control circuit terminal B and ground

⇒ | If less than the specified range, test the K20 Engine Control Module (ECM) control circuit for a short to ground or an open high resistance. If circuit tests normal, replace the K20 Engine Control Module (ECM).

⇒ | If greater than the specified range, test the K20 Engine Control Module (ECM) control circuit for a short to voltage. If circuit tests normal, replace the K20 Engine Control Module (ECM).

4. Ignition OFF, connect the EL-34730-405 Injector Test Lamp between the K20 Engine Control Module (ECM) control circuit terminal B and the ignition voltage circuit terminal A.
5. Engine idling, the test lamp should flash.

⇒ | If the test lamp does not flash, test the fuel injector circuits for a high resistance. If circuits test normal, replace the K20 Engine Control Module (ECM).

6. If all circuits test normal, test or replace the appropriate Q17 Fuel Injector.

### Component Testing

#### Static Test

1. Ignition OFF, disconnect the harness connector at the appropriate Q17 Fuel Injector.

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

2. Test for 11-14 Ω between the appropriate Q17 Fuel Injector ignition voltage terminal A and the K20 Engine Control Module (ECM) control circuit terminal B.

⇒ | If not within the specified range, replace the appropriate Q17 Fuel Injector.

### Repair Instructions

Perform the Diagnostic Repair Verification

• | LINK (Fuel Injector Replacement)

• | Control Module References