Fuel Pump Relay: Testing and Inspection
Fuel Pump Relay And Connections, Checking
The fuel pump relay is located at relay position 4 on the relay panel on the left side under the instrument panel.
Checking function of fuel pump relay -J17-
- Remove storage shelf in left-front footwell.
- Remove fuses 28, 29 and 34 from fuse panel.
- Connect VAG 1527B LED voltage tester between Ground and one of the two terminals for fuse 28.
- Briefly crank starter.
- LED test light must light up.
- Fuel pump relay must be actuated (sound and vibration)
If the fuel pump does not respond:
- Check power supply wiring.
If the LED test light does not light up:
- Repeat test at other terminal of fuse 28.
If the LED light still does not light up:
- Check wiring for open or short circuits between fuse 28 and terminal 30 at relay position 6, using the applicable wiring diagram. Repair wiring as necessary.
- Connect VAG 1527B LED voltage tester between Ground and one of the two terminals for fuse 29.
NOTE: This step lets the fuel pump run without the engine running. The closed throttle position switch must be closed during the test, or the selected fuel injector will discharge fuel when it is actuated 5 times.
- Initiate output Diagnostic Test Mode (DTM) and advance to test of cylinder 1 fuel injector -N30-. Refer to "Oxygen Sensor Behind Catalyst/Sensor and Sensor Control"
- LED test light must light up
- Fuel pump relay must be activated
- Fuel pump must run
If the LED test light does not light up:
- Repeat test at other terminal of fuse 29.
If the LED test light does not light up:
- Check wiring for open circuit between fuse 29 and terminal 30 at relay position 6, using the applicable wiring diagram. Repair wiring as necessary.
- Connect VAG 1527 LED voltage tester between Ground and one of the two terminals of fuse 34.
NOTE: This step lets the fuel pump run without the engine running. The closed throttle position switch must be closed during the test, or the selected fuel injector will discharge fuel when it is actuated 5 times.
- Initiate output Diagnostic Test Mode (DTM) and advance to test of cylinder 1 fuel injector -N30-. Refer to "Oxygen Sensor Behind Catalyst/Sensor and Sensor Control"
- LED test light must light up
- Fuel pump relay must be activated
- Fuel pump must run
If the LED test light does not light up:
- Repeat test at other terminal of fuse 34.
If the LED test light does not light up:
- Check wiring for open circuit between fuse 34 and terminal 31 at relay position 6, using the applicable wiring diagram. Repair wiring as necessary.
Checking fuel pump relay voltage supply
- Remove fuel pump relay -J17- from relay panel position 6.
- Switch ignition on.
- Connect multimeter US 1119 (Fluke 83 or similar) and check for voltage at relay socket:
- Terminals 28 (B+) and 34
- Terminals 32 (B+) and 34
- Specified values: approx. Battery Positive Voltage (B+)
If voltage is NOT OK:
- Repair wiring according to applicable wiring diagram.
Checking fuel pump relay signal
- Fuel pump relay -J17- removed
- Fuses 28, 29 and 34 removed from fuse panel
- Connect VAG 1527B LED voltage tester between relay socket terminals 28 (B+) and 29.
LED test light must light up (dimly).
- Briefly crank starter; LED test light must continue to light up (dimly).
If the LED test light does not light up while cranking the starter, check wiring as follows.
- Connect VAG 1598/22 test box to ECM harness connector. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1598/22 Test Box" Testing and Inspection (Numbers marked on ECM connector match those on test box).
- Connect multimeter US 1119 (Fluke 83 or equivalent) to check for open circuit between relay socket terminal 29 and test box socket 4.
Specified value: max. 1 Ohms
If resistance is NOT OK:
- Repair wiring using applicable wiring diagram.
If the wiring is OK, but the LED test light does not light up:
- Replace Engine Control Module (ECM).
If the wiring is OK, and the signal to the fuel pump relay is OK:
- Replace fuel pump relay -J17-.
- Reinstall fuses.