Fuel Pump Relay: Testing and Inspection

Fuel Pump (FP) Relay -J17 And Relay Activation, Checking







NOTE: The fuel pump relay is located in the central electrics in the left-hand footwell, relay position 4


A - Checking Fuel Pump (FP) relay -J17
- Remove storage bin in front left-hand footwell







- Remove fuel pump fuse from fuse holder and connect diode test lamp VAG1527 between Ground and one of the two contacts for the fuel pump fuse.
- Operate starter briefly.

The fuel pump relay should pick up (can be felt and heard) and the diode test lamp should light up.
- If fuel pump relay does not pick up, check activation.
- If fuel pump relay picks up but diode test lamp does not light up, repeat test on other terminal.







- If diode test lamp still does not light up, test for open circuit in wiring between fuel pump fuse and terminal 23 in relay position 4. If necessary, rectify open circuit.
- If voltage supply, activation and wiring for fuel pump relay are OK, install new fuel pump relay.

B - Checking voltage supply and activation of fuel pump relay


NOTE: Activation of the fuel pump relay can also be tested using the final control diagnosis. Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM)" Testing and Inspection


- Remove fuel pump relay -J17 from central electrics, relay position 4.

Checking voltage supply
- Switch ignition on.







- Connect hand-held multimeter VAG1526 between Ground (GND) and relay panel contact 19 (B+; terminal 15 from ignition switch). Disconnect, then re-connect between Ground (GND) and relay panel contact 17(permanent B+; terminal 30 from battery).
Specification: approx. battery voltage in each case
- If values are not as specified, rectify open circuit.

Checking activation







- Connect diode test lamp VAG1527 between B+ and contact 16 on relay panel (Ground connection via engine control module).
- Operate starter briefly.
- The diode test lamp should light up and remain lit when the starter is operated.


NOTE: Diode test lamps with a low current draw do not go out completely but continue to glow faintly until the starter is operated.


- If activation, wiring and power supply for fuel pump relay are OK but fuel pump relay still does not pick up, replace fuel pump relay.

If the diode test lamp does not light up, test the wiring as follows:
- Connect VAG1598/31 test box to wiring harness for engine control module. Do not connect to the engine control module itself. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG1598/31 Test Box" Testing and Inspection
- Connect hand-held multimeter between contact 16 on relay panel and socket 65 on the test box, then test wiring for open circuits.
- Rectify open circuit if necessary.

If there is no open circuit and the diode test lamp still does not light up:
- Replace Engine Control Module (ECM).
- Reinstall fuel pump fuse.