Diagnostic Instructions
DTC Descriptor
DTC P0181: Fuel Temperature Sensor Performance
Circuit/System Description
The fuel temperature sensor is a thermistor. The engine control module (ECM) supplies the fuel temperature sensor a bias voltage of 5 volts on the signal circuit and also provides a low reference circuit to the sensor. When the fuel temperature
sensor is cold, the resistance is high. The fuel temperature sensor signal voltage remains near the bias voltage cold and decreases as the sensor warms. The ECM monitors the fuel temperature sensor signal circuit in order to calculate the temperature of the
fuel entering the engine.
Conditions for Running the DTC
| • | DTCs P0112, P0113, P0182 and P0183 are not set. |
| • | The ignition must be turned OFF for 10 hours or longer. |
| • | The intake air temperature (IAT) sensor 1 is more than 10°C (50°F) at start-up. |
| • | DTC P0181 will only run once per ignition cycle until a Pass, Fail, or Disable conditions exists. |
Conditions for Setting the DTC
| • | The fuel temperature and the IAT Sensor 1 are more than 100°C (180°F) of each other at start-up. |
| • | The fuel temperature and the IAT Sensor 1 are more than 10°C (18°F) of each other at start-up. |
| • | The IAT has not dropped more than 2.5°C (4.5°F) after running more than 6 minutes above 24 km/h (15 mph). |
Action Taken When the DTC Sets
DTC P0181 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0181 is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
Circuit/System Verification
Important: If DTC P0112, P0113, P0182, or P0183 are set, refer to
Diagnostic Trouble Code (DTC) List - Vehicle
.
- Turn ON the ignition and observe the Fuel Temperature Sensor parameter with a scan tool. The fuel temperature parameter should be within -38 to +120°C (-38.4 to +248°F).
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the fuel temperature sensor.
- Test for less than 5 ohms between the low reference circuit terminal 2 and ground.
| ⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
- Ignition ON, verify the scan tool Fuel Temperature Sensor parameter is less than -39°C (-38°F).
| ⇒ | If temperature is warmer than the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the ECM. |
- Install a 3A fused jumper wire between the signal circuit terminal 1 and a ground, Verify the scan tool Fuel Temperature Sensor parameter is greater than 120°C (248°F).
| ⇒ | If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
- If all circuits test normal, test fuel temperature sensor and IAT sensor.
Component Testing
Fuel Temperature Sensor
Measure and record the resistance between the signal terminal 1 and the low reference circuit terminal 2 at the fuel temperature sensor. Compare the value to the Temperature vs. Resistance table. Refer to
Temperature Versus Resistance
.
| ⇒ | If the sensor does not closely match through the temperature ranges, replace the fuel temperature sensor. |
IAT Sensor
Measure and record the resistance between the signal terminal 5 and the low reference circuit terminal 4 at the IAT sensor. Compare the value to the Temperature Vs Resistance table. Refer to
Temperature Versus Resistance
.
| ⇒ | If the IAT sensor does not closely match the temperature ranges, replace the MAF/IAT sensor. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Fuel Temperature Sensor Replacement
