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 P0180 03: Fuel Temperature Sensor Circuit Voltage Below Threshold
DTC P0180 07: Fuel Temperature Sensor Circuit Voltage Above Threshold
DTC P0182: Fuel Temperature Sensor Circuit Low Voltage
DTC P0183: Fuel Temperature Sensor Circuit High Voltage

### Circuit/System Description

The fuel temperature sensor is integrated within the fuel filter assembly. The fuel temperature sensor is a variable resistor that measures the temperature of the fuel. The engine control module (ECM) supplies 5 volts to the signal circuit and supplies a ground to the low reference circuit. The following table illustrates the difference between temperature, resistance, and voltage:

Fuel Temperature Sensor | Resistance | Signal Voltage
--- | --- | ---
Cold | High | High
Warm | Low | Low

### Conditions for Running the DTC

• | The ignition is ON or the engine is operating.

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

### Conditions for Setting the DTC

#### P0180 03 or DTC P0182

The ECM detects that the fuel temperature sensor voltage is less than 0.127 volt for 0.5 seconds.

#### DTC P0180 07 or P0183

The ECM detects that the fuel temperature sensor voltage is greater than 4.9 volt for 0.5 seconds.

### Action Taken When the DTC Sets

DTCs P0180, P0182, and P0183 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0180, P0182, and P0183 are Type B DTCs.

### Diagnostic Aids

• | A short to a separate 5-volt source may set a DTC P0183.

• | A skewed sensor could result in poor driveability concerns.

### 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. Engine idling, DTC P0180 03, P0180 07, DTC P0182, or P0183 should not set.
2. 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, and the MAIN fuse removed, disconnect the harness connector at the fuel filter assembly.
2. Test for less than 5 ohms of resistance between the low reference circuit terminal 6 and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.

3. Install the MAIN fuse. Ignition ON, verify that the scan tool fuel temperature sensor parameter is at 5 Volts.

⇒ | If less than the specified value, test the signal circuit for a short to ground. If the circuit/connections test normal, replace the ECM.

Notice: Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw.

Important: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.

4. Install a 1A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool fuel temperature sensor parameter is at 0 Volts.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.

5. If all circuits test normal, replace the fuel temperature sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Fuel Heater Replacement

• | Control Module References for ECM replacement, setup, and programming