Fuel Pump (FP) Relay -J17-, Testing and Activating

Fuel Pump (FP) Relay -J17-, Testing And Activating







Special tools and equipment
- VAG 1526 A
- VAG1594A
- VAG 1598/31
- VAS 5051 with VAS 5051/1

The fuel pump and some of the injection system components receive their voltage supply via fuel pump (FP) relay -J17-.

Fuel pump (FP) relay -J17-will only close if the engine is turning over. In other words, the relay is only Grounded (via the engine control module) when the engine control module is receiving engine revolution impulses.

Test requirement:
- Battery voltage not less than 12.7 V

Testing operation of fuel pump relay
- Remove storage compartment on driver's side.
- Connect the vehicle diagnostic, testing and information system VAS 5051, Vehicle Diagnostic, Testing and Information System VAS 5051, Connecting and Selecting Functions , and select the vehicle system "01 - Engine electronics" from the menu. When doing this the ignition should be switched on.
- Start output diagnostic test mode, Output Diagnostic Test Mode (Function 03) and activate evaporative emission (EVAP) canister purge -N80-.







- The fuel pump relay should pick up and the fuel pump should run. (Relay is located in relay position 4 in micro central electrics on left of driver's footwell).

A - If the relay does not pick up:
- Test voltage supply to fuel pump relay.
- Test activation of fuel pump relay.
B - If the relay picks up but the fuel pump does not run:
- Test voltage supply to fuel pump and other components (via fuel pump relay).

Testing voltage supply to fuel pump relay
- Disconnect fuel pump relay.







- Connect multimeter (voltage measurement range) to Ground and contact 17 on relay panel.
- Specification: approx. battery voltage

If the specification is not obtained:
- Replace central electrics unit

Testing activation of fuel pump relay
- Switch off ignition.
- Connect test box VAG 1598/31 to wiring harness for engine control module. Do not connect to the engine control module itself. Scan Tool Testing and Procedures
- Bridge contacts 1 and 65 on the test box using test leads from adapter set VAG 1594 A.
- Switch on ignition.







- The fuel pump relay should pick up. (Relay is located in relay position 4 in micro central electrics on left of driver's footwell).

If the relay picks up now but not during the output diagnostic test mode:
- Install a new engine control module.

If the relay does not pick up:
- Switch off ignition.
- Disconnect cable bridge.
- Disconnect fuel pump relay.







- Connect multimeter (voltage measurement range) as follows:

Central electrics on left of Measure against
driver's footwell, position 4
Contact
19 Engine Ground

- Switch on ignition.
- Specification: approx. battery voltage

If the specification is not obtained:
- Check the wiring.

If the specification is obtained:
- Test for open circuit and short to positive or Ground in the following wiring connection:

Central electrics on left of Test box VAG 1598/31
driver's footwell, relay Socket
position 4 Contact
16 65

- Correct any open/short circuit as necessary.

If no malfunction is found:
- Install a new fuel pump (FP) relay -J17-.
- Reconnect the engine control module.

Testing voltage supply to fuel pump and other components







- Remove fuse Nos. S228, S232, S234 and S243 (sockets 28, 32, 34 and 43) from fuse holder.
- Start output diagnostic test mode, Output Diagnostic Test Mode (Function 03) and activate evaporative emission (EVAP) canister purge -N80-.
- For each of the following fuse positions in the fuse holder, connect the multimeter (voltage measurement range) between Ground and one of the fuse contacts:

Fuse Specification (for one contact)
S228 Approx. battery voltage
S232 Approx. battery voltage
S234 Approx. battery voltage
S243 Approx. battery voltage

If the specifications are not obtained:
- Repeat the test on the other fuse contact.

If the specifications are again not attained:
- Check wiring

If no fault is found:
- Install a new fuel pump (FP) relay -J17-.
- Install fuses.