Fuel Pump Relay: Testing and Inspection

Fuel pump relay and connections, checking


NOTE:
- Voltage to the fuel pump and certain injection components is supplied through the fuel pump relay -J17-.
- The fuel pump relay -J17- is activated only with the engine running. The relay receives a ground through the Engine Control Module (ECM) after the ECM detects an RPM signal.

Required special tools and test equipment
- VAG 1551 or VAG 1552 Scan Tool (ST) with VAG 1551/3 adapter cable
- VAG 1598/22 test box
- Multimeter US 1119 (Fluke 83 or equivalent)
- VW 1594 connector test kit
- Wiring diagram

Testing requirements
- Battery voltage - minimum 11 volts

Checking function of fuel pump relay -J17-
- Initiate output Diagnostic Test Mode (DTM) and advance to test of cylinder 1 fuel injector -N30-.Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03)" Testing and Inspection

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 be activated 5 times discharging fuel.







The fuel pump relay (on relay panel position 4) must engage.
- If relay doesn't engage, check actuation of fuel pump relay.
- If fuel pump doesn't run, check actuation of fuel pump and components.

Actuation of fuel pump relay, checking
- Switch ignition off.
- 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
- Using test leads from VAG 1594, connect test box sockets 2 and 4.
- Switch ignition on

The fuel pump relay must engage.

If the relay engages now, but didn't during the output Diagnostic Test Mode (DTM):

- Replace ECM.
- Carry out adaptation of throttle valve control module to ECM.
- Check readiness code.If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code.
Refer to "Moniters, Trips and/or Drive Cycle (Readiness Codes)/Checking Readiness Code" Testing and Inspection
Refer to "Moniters, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code Testing and Inspection

If the relay doesn't engage:
- Switch ignition off.







- Remove fuel pump relay from its socket in relay panel.
- Connect multimeter US 1119 (Fluke 83 or equivalent) to terminal 19 of relay panel socket and ground.
- Switch ignition on.
Specified value: battery voltage

If the specified value is not obtained:
- Repair wiring using applicable wiring diagram.

If the specified value is obtained:
- Switch ignition off.







- Connect multimeter US 1119 (Fluke 83 or equivalent) to socket terminal 16 of relay position 4 in relay panel and VAG 1598/22 test box socket 4.

- Check wiring for open circuit or short circuit to B+ or Ground.

If wiring is OK:
- Replace fuel pump relay -J17-.

Checking actuation of fuel pump and components







- Remove fuses 28, 29, and 34 from fuse panel.
- Initiate output Diagnostic Test Mode (DTM) and advance to test of cylinder 1 fuel injector -N30-.Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03)" Testing and Inspection


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 be activated 5 times discharging fuel.


- Connect multimeter between Ground and left or right terminal of following fuses:

Fuse number Specified voltage at left or right terminal

28 approx. battery voltage
29 approx. battery voltage
34 approx. battery voltage

If the specified value is not obtained:
- Repair wiring using applicable wiring diagram.

If wiring is OK:
- Replace fuel pump relay -J17-.