Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fuel Temperature Sensor, Checking
Observe all safety precautions: SAFETY PRECAUTIONS
View clean working conditions: CLEAN WORKING CONDITIONS
Prior to repair work, perform a preliminary check to verify the condition. Refer to PRELIMINARY CHECK .
Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.
See Appropriate Wiring Diagram Information for component locations and connector views.
Special Tools And Workshop Equipment Required
- Multimeter
- Wiring diagram
Test Requirements
- The engine control module fuses OK
- Battery voltage at least 12.5 volts
- All electrical consumers switched off
- Vehicles with automatic transmission, shift selector lever in park or neutral
- A/C switched off
- Ground connections between engine/transmission/chassis OK
Test Procedure
-- Disconnect the Fuel Temperature Sensor -G81- electrical harness connector.
Checking internal resistance
-- Using a multimeter, measure the resistance between the terminals of the Fuel Temperature Sensor -G81-.
Use The Chart Below To Estimate The Specified Values:
| Fuel temperature | Sensor resistance |
|---|---|
| 20 °C (68 °F) | 1950 to 2200 Ω |
If The Sensor Value Was Not Within The Specified Range:
-- Replace the Fuel Temperature Sensor -G81-.
Checking the voltage
-- Disconnect the Fuel Temperature Sensor -G81- connector.
-- Turn the ignition switch ON.
-- Using a multimeter, measure the voltage between the Fuel Temperature Sensor -G81- terminal 2 and ground.
Specified Value: Near 5.0 V
If The Specification Was Obtained:
-- Using a multimeter, measure the voltage between the Fuel Temperature Sensor -G81- terminals 2 and 1.
Specified Value: Near 5.0 V
If The Voltages Above Were Not Obtained:
Checking the wiring
-- Remove the Engine Control Module (ECM) -J623-. Refer to the appropriate Service Information for removal and installation procedures.
| Fuel Temperature Sensor -G81- electrical harness connector terminal | Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminals |
|---|---|
| 1 | 53 |
| 2 | 42 |
-- Using a multimeter, measure the resistance of circuits between the Fuel Temperature Sensor -G81- and the Engine Control Module (ECM) -J623- electrical harness connectors. Refer to the applicable wiring diagram. Refer to Appropriate Wiring Diagrams for Pin locations.
Specified Value: 1.5 Ω Max.
If The Specification Was Not Obtained:
-- Check the wires for high resistance, a short circuit to each other, a short to battery voltage, and a short to ground.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- Repair as necessary.
If No Malfunction Is Detected In The Sensor Or Wiring:
-- Replace the Engine Control Module (ECM) -J623-. Refer to the appropriate Service Information for removal and installation procedures.
Final Procedures
After repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.