Fuel Pump Relay: Testing and Inspection

Voltage is supplied to the Fuel Pump (FP) and several components of the injection system via the Fuel Pump (FP) relay - J17 -.
For Fuel Pump (FP) relay - J17 - to close, it is required that engine is turning. This means that the relay does not receive Ground (via ECM) until the ECM recognizes RPM signals.







NOTE:
Fuel Pump (FP) relay is located at position 4 of micro-central electrics in driver's footwell, left.


Test requirement
- Battery voltage at least 11 V

Function test of Fuel Pump (FP) relay
- Remove driver - side storage compartment.
- Connect VAS5051 tester or VAG 1551 scan tool and select control module for engine electronics using "address word" 01.
Ignition must remain switched on for this.
- Initiate Output Diagnostic Test Mode and activate Evaporative Emission (EVAP) canister purge regulator valve - N80.
- Fuel Pump (FP) relay (at position 4 of micro - central electrics in driver's footwell, left) must trigger and Fuel Pump (FP) must run

If relay does not trigger:
- Check activation of Fuel Pump (FP) relay.

If Fuel Pump (FP) does not run:
- Check voltage supply for Fuel Pump (FP) and components (via Fuel Pump - FP - relay).

Check activation of Fuel Pump (FP) relay
- Switch ignition oft.
- Connect VAG 1598/31 test box at wiring harness to ECM, do not connect ECM.
- Connect socket 65 and socket 2 of test box to each other using wire from VAG 1594 connector test kit.
- Switch ignition on.
- Fuel Pump (FP) relay (at position 4 of micro-central electrics in driver's footwell, left) must trigger

If relay triggers now, but didn't during output DTM:
- Replace Engine Control Module (ECM).

If relay does not trigger:
- Switch ignition off.
- Remove Fuel Pump (FP) relay.







- Connect multimeter to terminal 19 of relay socket and Ground for voltage measurement.

If specified value is obtained:
- Switch ignition off.

- Check the following wire connection for open circuit and short circuit to Ground and B+ :

Micro-central electronics in VAG 1598/31 test box socket
drivers-side foot-well, left,
position 4 terminal
16 65

- Repair open circuit or short circuit if necessary.
- If wire connections are OK, replace Fuel Pump (FP) relay - J17 -

Check voltage supply for Fuel Pump (FP) and components







- Connect multimeter to Ground and to one terminal of the following fuses in fuse holder for voltage measurement.

Locking clip Specified one of the terminals
S28 approx. battery voltage
S32 approx. battery voltage
S34 approx. battery voltage
S43 approx. battery voltage

If specified values are not obtained:
- Repeat test at another terminal of fuse socket.

If specified values are not obtained again:
- Check wire connections.
- If wire connections are OK, replace Fuel Pump (FP) relay - J17-.