Fuel Temperature Sensor
Special Tools, Testers And Auxiliary Items:- VAG 1551/1552 Scan Tool with VAG 1551/3 adaptor cable
- VAG 1598/18 Test Box
- Fluke 83 multimeter (or equivalent)
- VW 1594 adaptor kit
- Wiring diagram
Test Sequence:
- Connect VAG 1551/1552 Scan Tool
- Start engine and let idle
- Press 0 and 1 buttons to select address word 01 "engine electronics"
Display will appear as shown:
Rapid data transfer HELP
select function XX
- Press 0 and 8 buttons to select Function 08 "Read measuring value block"
- Press Q button to enter input
Display will appear as shown:
Read measuring value block HELP
Input display group number XXX
- Press 0, 0 and 7 buttons to select "display group 7"
- Press Q button to enter input
Display will appear as shown:
Read measuring value block 7 ->
15.4°C 15.9°C 16.7°C
If either an implausible value appears in display zone 1 or a substitute temperature of -5.4°C is displayed, check fuel temperature sensor and wiring to the sensor as follows:
- Press -> button
- Press 0 and 6 buttons to select Function 06 "end data transfer"
- Press Q button to enter input
- Switch OFF ignition
- Disconnect fuel temperature sensor harness connector (connection to injection pump metering control)
- Measure sensor resistance at terminals 4 + 7
Specification, see diagram
Scale A shows resistance values for temperature range 0 to 50°C
Scale B the values for temperature range 50 to 100°C.
Examples:
30°C corresponds to a resistance from 1500 to 2000 Ohms
80°C corresponds to a resistance from 275 to 375 Ohms
If the specification is not obtained:
- Replace injection pump
- Display the readiness code
If DTC memory was erased:
- Create readiness code again
If specification obtained:
- Connect Test Box VAG 1598/18 to ECM harness connector
- Check wiring for open circuit between Test Box and connector -1- using wiring diagram:
terminal 7 + socket 63
terminal 4 + socket 33
Wire resistance: 1.5 Ohms maximum.
Also check wires for shorting to one another
Specification: Infinite Ohms.
If wiring OK:
- Replace Diesel direct injection system ECM J248
- Display the readiness code
If DTC memory was erased:
- Create readiness code again