For 1990-2009 cars

## Fuel Injector Solenoid Coil Test w/LLT

### 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.

### Circuit/System Description

The engine control module (ECM) enables the appropriate fuel injector pulse for each cylinder. The ECM supplies a high voltage control circuit and a low control circuit to each of the fuel injectors. The control module controls each fuel injector control circuit via a solid state device called a driver. A fuel injector coil winding resistance that is too high or too low will affect the engine driveability. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.

### Diagnostic Aids

• | Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.

• | If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool Fuel Injector Circuit Test Status parameter. The Fuel Injector Circuit Test Status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Component Testing

Important:

• | The engine coolant must be within the specified range or mis-diagnosis will occur.

• | The resistance test must be performed at the fuel injector or mis-diagnosis will occur.

• | The DMM and test leads must be calibrated to 0 ohms in order to prevent mis-diagnosis.

1. Engine coolant between 10-32°C (50-90°F).
2. Test for 1.30-1.73 ohms between the terminals of the fuel injector. The resistance of each fuel injector should be 1.30-1.73 ohms.

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Fuel Injector Replacement