Fuel Pump Relay: Testing and Inspection

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

Special Tools and Equipment







- VAG1526A
- VAG1594A
- VAG1598/31
- VAS5051 with VAG5051/1
- or
- VAG1551 with VAG1551/3B

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.


NOTE:







Fuel Pump (FP) relay is located at position 4 of central electrics in driver's footwell, left.


Test requirement:
- Battery voltage at least 12.7 V

Function test of Fuel Pump (FP) relay
- Remove driver-side storage compartment.
- Connect VAS5051 tester or VAG1551 scan tool and select the control module for engine electronics using "address word" 01. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAS5051/VAG1551 Scan Tool" Testing and Inspection
Ignition must remain switched on for this.
- Initiate output Diagnostic Test Mode and activate Evaporative Emission (EVAP) canister purge regulator valve -N80-. Refer to Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03) Testing and Inspection







- Fuel Pump (FP) relay (at position 4 of central electrics in driver's footwell, left) must trigger and Fuel Pump (FP) must run.
A - If relay does not trigger:
- Check voltage supply of Fuel Pump (FP) relay.
- Checking activation of Fuel Pump (FP) relay.
B - If relay triggers, but 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 to terminal 17 of relay socket and Ground (GND) for voltage measurement.
- Specification: approx. battery voltage

If specified value is not obtained:
- Replace central electrics.

Checking activation of Fuel Pump (FP) relay
- Switch ignition off.
- Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG1598/31 Test Box" Testing and Inspection
- Bridge terminals 1 and 65 at test box using wires from VAG1594A adapter test kit.







- Fuel Pump (FP) relay (at position 4 of central electrics in driver's footwell, left) must trigger.

If relay triggers now, but didn't during output DTM:
- Replace Engine Control Module (ECM).

If relay does not trigger:
- Remove cable bridge.
- Remove Fuel Pump (FP) relay.







- Connect multimeter to terminal 19 of relay socket and Ground GND) for voltage measurement .
- Specification: approx. battery voltage

If specified value is not obtained:
- Check wire connections.

If specified value is obtained:







- Check the following wire connection for open circuit and short circuit to Ground (GND) and B+:







- Repair open circuit or short circuit if necessary.

If no malfunctions are detected:
- Replace Fuel Pump (FP) relay -J17-.
- Re-connect Engine Control Module (ECM).

Check voltage supply for Fuel Pump (FP) and components







- Remove fuses S228, S229, and S234 (positions 28, 29, and S234) from fuse holder.
- Initiate output Diagnostic Test Mode and activate Evaporative Emission (EVAP) canister purge regulator valve -N80-. Refer to Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03) Testing and Inspection
- Connect multimeter for voltage measurement to Ground (GND) and to one terminal of the following fuses in the fuse holder.







If specified values are not obtained:
- Repeat test at another terminal of fuse socket.

If specified values are not obtained again:
- Check wire connections.

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