With Generic Scan Tool

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

Recommended special tools and equipment







- VAG1526A hand multimeter
- VAG1594A connector test kit
- VAG1598/31 test box

Voltage is supplied to the Fuel Pump (FP) and several components of the injection system via the Fuel Pump (FP) Relay -J17-.

Engine must be turning for Fuel Pump (FP) Relay -J17- to close. This means that the relay does not receive Ground (GND) (via ECM) until the ECM recognizes RPM signals.

Test requirements:
- Battery voltage at least 12.5 V
- Ignition switched off.

Function test of Fuel Pump (FP) relay
- Remove driver-side storage compartment
- Connect test box to wiring harness of Engine Control Module (ECM); ECM is not connected.
- Bridge terminals 1 and 65 at test box using wires e.g. from V.A.G 1594 A adapter test kit.
- Switch ignition on.







- Fuel Pump (FP) relay (position 1, at 9-pin relay carrier in driver's footwell, left) must trigger and Fuel Pump (FP) must run.

A - If Fuel Pump (FP) runs:
- Check voltage supply of Fuel Pump (FP) relay
- Checking activation of Fuel Pump (FP) relay

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

Check voltage supply of Fuel Pump (FP) relay
- Remove Fuel Pump (FP) relay.







- Connect multimeter for voltage measurement as follows.

9-pin relay carrier in driver's footwell, left side, position 1 Measure to
Terminal
1 Chassis Ground (GND)

- Specified value: approx. battery voltage

- Connect multimeter for voltage measurement as follows:

9-pin relay carrier in driver's footwell, left side, position 1 Measure to
Terminal
3 Chassis Ground (GND)

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

- Switch ignition off.

If specified values are not obtained:
- Check wire connections for open circuit according to wiring diagram.
- Specified value: Wire resistance max 1.5 Ohm

If specified values are obtained:

Checking activation of Fuel Pump (FP) relay
- Remove cable bridge.
- Remove Fuel Pump (FP) relay.
- Connect test box to wiring harness of Engine Control Module (ECM); ECM is not connected.







- Check the following wire connection for open circuit according to wiring diagram:

9-pin relay carrier in driver's footwell, left side, position 1 Test box Socket
Terminal
5 65

- Specified value: Wire resistance max 1.5 Ohm

- Also check the wire for short circuit to B+ and Ground (GND).
- Specified value: Infinite Ohm (no continuity)

- If necessary, repair wire connection.

If no malfunctions are detected:
- Replace Fuel Pump (FP) Relay -J17-.

or

- Replace Engine Control Module (ECM).

Check voltage supply for Fuel Pump (FP) and components







- Remove fuses S228, S232, and S234 (positions 28, 32, and 34) from fuse holder.
- Connect multimeter for voltage measurement to Ground (GND) and to one terminal of the following fuses in the fuse holder.
- Operate starter briefly.

Fuse Specified value at one of the terminals
S228 approx. battery voltage
S232 approx. battery voltage
S234 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 for open circuit according to wiring diagram.
- Specified value: Wire resistance max 1.5 Ohm

If no malfunctions are detected:
- Replace Fuel Pump (FP) Relay -J17-.
- Re-insert the fuses.

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1 - Check DTC memory, see "Mode 3: Check DTC memory".
2 - If necessary, erase DTC memory, see "Mode 4: Reset/erase diagnostic data".
3 - Generate readiness code. With Generic Scan Tool

- End diagnosis and switch ignition off.