Fuel Pump Relay: Testing and Inspection

CHECKING FUEL PUMP RELAY -J17-:
- Remove storage unit in left-front footwell.
- Remove trim from A-pillar, lower right.
- Pull back carpet in right floor outlet, remove cover from electronics box.
- Remove circuit breakers -2- and -3- (brown and red holders).
- Remove fuse 17 from fuse panel.
- Connect VAG 1527B voltage tester between Ground (GND) and either of the fuse 28 terminals using jumper wires from the connector test kit VW 1594.
- Briefly operate starter.
- Fuel pump relay must be felt and heard ("click").
- Voltage tester must light up.

If fuel pump relay does not operate:
- Check triggering.

If voltage tester does not light up:
- Repeat test on other terminal for fuse 17.

If voltage tester still does not light up:




- Check wiring between fuse 17 and socket 30 at relay position 6, and repair as necessary.




- Connect voltage tester between Ground (GND) and each terminal of fuse 29, in sequence.
- Use scan tool "Output Diagnostic Test Mode" function 03 to trigger fuel pump relay -J17-.
- Fuel pump relay must be felt and heard ("click").
- Voltage tester must light up.

If voltage tester does not light up:
- Repeat test at terminal 2 of red circuit breaker holder.

If voltage tester still does not light up:




- Check wiring for continuity between circuit breaker holder and socket 31 at relay position 6, and repair open circuit as necessary.




- Connect voltage tester between Ground (GND) and brown circuit breaker holder, terminal 1.
- Use scan tool "Output Diagnostic Test Mode" function 03 to trigger fuel pump relay -J17 -.
- Fuel pump relay must be felt and heard ("click").
- Voltage tester must light up.

If the voltage tester does not light up:
- Repeat test at terminal 2 of brown circuit breaker holder.

If the voltage tester still does not light up:




- Check wiring for continuity between circuit breaker holder and socket 30 at relay position 6 according to wiring diagram, and repair open circuit as necessary.

CHECKING VOLTAGE SUPPLY:
- Remove fuel pump relay -J17- from the fuse relay panel, relay position 6.
- Switch ignition ON.
- Connect multimeter (Fluke 83 or equivalent) between sockets 28 (B+) and 34, then between sockets 32 (B+) and 34.
- Specified value: approx. battery positive voltage (B+).

If the specified values are not obtained:
- Check for open circuit using wiring diagram, correct as necessary.

CHECKING FUEL PUMP RELAY TRIGGERING:




- Connect voltage tester between sockets 28 (B+) and 29.
- Voltage tester must light up for approx. 1 second and then go out. Tester must stay lit while operating starter.

NOTE: Only by operating the starter is it possible to make the voltage tester LED go out, otherwise it will appear dimly lit (due to low current draw).




If voltage tester does not light up, check wiring as follows:
- Connect VAG 1598/19 test box to ECM harness connector (ECM is left disconnected).
- Switch multimeter (Fluke 83 or equivalent) to measure resistance (Ohms) and check for continuity between relay socket 29 and test box socket A5 using jumper wires from connector test kit VW 1594.
- Specified value: max. 1 Ohms.

If the specified value is not obtained:
- Check for open circuit using wiring diagram, and correct as necessary.

If the wiring is OK and the voltage tester does not light up:
- Replace ECM.

If the fuel pump relay triggering and the wiring is OK:
- Replace the fuel pump relay.
- Re-insert the removed fuses.