Fuel Pump Relay and Relay Activation, Checking
Fuel Pump Relay and Relay Activation, Checking
Special tools, testers and auxiliary items required
• Multimeter (V.A.G 1526 A)
• Connector test kit (V.A.G 1594 A)
• Test Box (VAG1598/31)
• Vehicle diagnostic, testing and information system ( VAS 5051)
• Adapter (VAS 5051/1)
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.
• The fuel pump relay is located on the 9-unit- relay carrier on the left in the driver's footwell, position 1.
Requirements
• Battery voltage at least 12.7 V
Functional check of Fuel Pump (FP) Relay (J17)
- Remove driver's storage compartment.
- Connect vehicle diagnostic, testing and information system (VAS 5051) and select vehicle system "01 -Engine electronics" in selection. Refer to => [ VAS5051, Connecting and Selecting Functions ] VAS 5051, Connecting and Selecting Functions. Ignition must be switched on.
- Initiate Output Diagnostic Test Mode (DTM) and activate ACF solenoid valve (N80). Refer to => [ Output Diagnostic Test Mode ] Output Diagnostic Test Mode.
• Fuel pump relay (on the 9-unit-relay carrier in the driver's footwell on the left, position 1) should pull and fuel pump should run.
A - If relay does not respond:
- Check voltage supply of Fuel Pump (FP) Relay ( J17).
- Check activation of Fuel Pump (FP) Relay (J17 ).
B - If relay is energized but fuel pump does not run:
- Check voltage supply for fuel pump and components (via Fuel Pump (FP) Relay (J17)).
Checking voltage supply of Fuel Pump (FP) Relay (J17)
- Disconnect Fuel Pump (FP) Relay (J17).
- Connect multimeter as follows to measure voltage.
• Specified value: Approx. battery voltage
- Connect multimeter as follows to measure voltage:
- Switch ignition on.
• Specified value: Approx. battery voltage (B+)
If specified values are not obtained:
- Check wiring connections.
If specifications are obtained:
Checking activation of Fuel Pump (FP) Relay (J17)
- Switch ignition off.
- Re-insert relay.
- Connect test box (VAG1598/31) to wiring harness for engine control module; do not connect to engine control module (ECM). Refer to => [ Electrical Testing, with Test Box VAG 1598/31 ] Electrical Testing, With Test Box VAG 1598/31.
- Switch ignition on.
- Jumper terminals 1 and 65 at test box with leads from adapter set V.A.G 1594A.
• Fuel Pump (FP) Relay (J17) (on the 9-unit-relay carrier in the driver's footwell on the left, position 1) should pull fuel and fuel pump should run.
If the relay responds now, but not during Output Diagnostic Test Mode (DTM):
- Replace Engine Control Module (ECM). Refer to => [ Engine Control Module without Metal Anti-Theft Housing, Replacing ] Engine Control Module Without Metal Anti-Theft Housing, Replacing.
If the relay does not respond:
- Switch ignition off.
- Disconnect cable link.
- Disconnect Fuel Pump (FP) Relay (J17).
- Check for open circuit, short to positive, or short to ground (GND) in following wiring connection:
- Repair any open/short circuit as necessary.
If no malfunction is found:
- Replace Fuel Pump (FP) Relay (J17).
- Reconnect ECM.
Checking voltage supply of fuel pump and components
- Disconnect fuses (S228), (S229) and (S234) (positions 28, 32 and 34) in fuse holder.
- Initiate Output Diagnostic Test Mode (DTM) and activate EVAP Canister Purge Regulator Valve (N80). Refer to => [ Output Diagnostic Test Mode ] Output Diagnostic Test Mode.
- To measure voltage, connect multimeter to Ground (GND) and to one terminal of following fuses in fuse holder.
If specified values are not obtained:
- Repeat test at other terminal of fuse base.
If specified values are still not obtained:
- Check wiring connections.
If no malfunction is found:
- Replace Fuel Pump (FP) Relay (J17).
- Reinstall fuses.