With Manufacturer's Scan Tool

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







Special tools and equipment required
- VAG 1526A
- VAG 1594A
- VAG 1598/31
- VAS5051 with VAS5051/1

The fuel pump and certain components of the injection system are supplied with power by way of the fuel pump (FP) relay-J17-.
The fuel pump (FP) relay -J17- is only energized when the engine is running, i.e. the relay is only connected to Ground (via the engine control module) when engine speed pulses are detected in the engine control module.

Test requirements:
- Battery voltage at least 12.7 V

Functional check of fuel pump relay
- Remove driver's storage compartment:
- Connect testing and information system VAS5051 and select vehicle system "01 Engine electronics". Ignition must be switched on. Connecting VAS 5051 Scan Tool
- Initiate Output Diagnostic Test Mode (DTM) and actuate evaporative emission (EVAP) canister purge regulator valve -N80-. Output Diagnostic Test Mode (DTM) (Function 03)







- Fuel pump relay (on central electronics in driver's footwell on left, position 4) must trigger and fuel pump must run.

A - If relay does not respond:
- Check voltage supply of fuel pump relay.
- Check activation of fuel pump relay.

B - If relay is energized but fuel pump does not run:
- Check voltage supply for fuel pump and components (via fuel pump relay).

Checking voltage supply of fuel pump relay







- Disconnect fuel pump relay.
- Connect multimeter as follows to measure voltage.

Central electronics in driver's Measure to
footwell on left, position 4
terminal
17 Chassis Ground (GND)

- Specified value: approx. battery voltage

If specified value is not obtained:
- Replace central electronics.
- Connect multimeter as follows to measure voltage:

Central electronics in driver's Measure to
footwell on left, position 4
terminal
19 Chassis Ground (GND)

- Switch ignition on.
- Specified value: approx. battery voltage

If the specified value is not obtained:
- Check wiring connections.

If specifications are obtained:

Checking activation of fuel pump relay

- Switch ignition off.
- Reconnect relay.
- Connect test box VAG 1598/31 to wiring harness for engine control module; do not connect engine control module. Wiring and Component Testing Using VAG1598/31 Test Box
- Bridge terminals 1 and 65 at test box with leads from adapter kit VAG 1594A.
- Switch ignition on.







- Fuel pump relay (on central electronics in the driver's footwell on the left, position 4) must trigger.

If the relay responds now, but not during output DTM:
- Replace engine control module.

If the relay does not respond:
- Switch ignition off.
- Disconnect cable link.
- Disconnect fuel pump relay.







- Check for open circuit and short to positive or Ground in following wiring connection:

Central electronics in driver's Test box
footwell on left, position 4 VAG 1598/31
terminal Socket
16 65

- Repair any open/short circuit as necessary.

If no DTC is found:
- Replace fuel pump (FP) relay -J17-.
- Reconnect engine control module.