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:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .