With Generic Scan Tool

Fuel Temperature Sensor, Checking

NOTE: Use only gold-plated terminals when servicing terminals in harness connector to injection pump quantity adjuster.

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test requirement





- The respective fuses of Diesel-Direct fuel injection system must be OK:
- Battery voltage must be at least 11.5 Volts.

Test sequence





- Disconnect 10-pin harness connector (arrow) for fuel temperature sensor (harness connector to injection pump quantity adjuster).






- Measure resistance of sensor at connector terminals 4 + 7.






See diagram for specified value

Range A displays resistance values for the temperature range of 0...50 degree C, range B displays resistance values for the temperature range of 50...100 degree C.

Read-out examples:
30 degree C corresponds to a resistance of 1500 to 2000 Ohm
80 degree C corresponds to a resistance of 275 to 375 Ohm

If specified value is not obtained:
- Replace injection pump, item 3. Procedures
- Erase DTC memory of control module for Diesel-Direct fuel injection system, Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specified value is obtained:
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test

Vehicles with 80-pin control module





- Check for open circuit in wires between test box and connector according to wiring diagram.
Terminal 4 + socket 76
Terminal 7 + socket 53
Wire resistance: max. 1.5 Ohm

Vehicles with 121-pin control module





- Check for open circuit in wires between test box and connector according to wiring diagram.
Terminal 7 + socket 111
Terminal 4 + socket 103
Wire resistance: max. 1.5 Ohm

Continuation for all vehicles
- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinite Ohm

If no malfunctions are detected in wires:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- Service and Repair
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes