Fuel Pump Relay: Testing and Inspection
Fuel Pump Relay -J17-, Checking And Checking Actuation
Fuel pump control module -J538- and certain injection system components are supplied with power by way of the Fuel pump relay -J17-.
A requirement for the energization of the Fuel pump relay -J17- is that the engine is running. In other words, Ground is not applied to the relay (via the engine control module) until engine speed pulses are detected in the engine control module.
Requirement
- Battery voltage at least 12.7 V
Checking operation of fuel pump relay
- Remove driver's storage compartment.
- Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 - Engine electronics" from list. Ignition must be on. Connecting VAS 5051 Scan Tool
- Start final control diagnosis and actuate EVAP canister purge regulator valve - N80-.
- Fuel pump relay (on central electrics on left in driver's footwell, position 4) must be energized and both fuel pumps (one in tank, other on outside) must run.
A If relay is not energized:
- Check power supply of fuel pump relay.
- Check actuation of fuel pump relay.
B If relay is energized but fuel pumps do not run:
- Check power supply from fuel pump relay to Fuel pump control module -J538- and components powered by fuel pump relay. Testing and Inspection
Checking power supply of fuel pump relay
- Disconnect fuel pump relay.
- Connect multimeter for voltage measurement as follows:
Central electrics on left in driver's Measure to
footwell, position 4 Contact
17 Body Ground
- Specification: approx. battery voltage
If reading does not match specification:
- Replace central electrics.
- Connect multimeter for voltage measurement as follows:
Central electrics on left in driver's Measure to
footwell, position 4 Contact
19 Engine Ground
- Switch on ignition.
- Specification: approx. battery voltage
If reading does not match specification:
- Check wiring.
If readings match specifications:
Checking actuation of fuel pump relay
- Switch off ignition.
- Re-insert relay.
- Connect test box V.A.G 1598/31 at wiring harness to engine control module. Actual engine control module is not to be connected. Wiring And Component Check Using Test Box V.A.G 1598/31
- Use leads from adapter set V.A.G 1594 A to jumper contacts 1 and 65 at test box.
- Switch on ignition.
- Fuel pump relay (on central electrics on left in driver's footwell, position 4) must be energized
If relay is now energized, but not during final control diagnosis:
- Replace engine control module.
If relay is not energized:
- Switch off ignition.
- Disconnect cable link.
- Disconnect fuel pump relay.
- Check for open circuit and short to Ground/positive in the following wiring:
Central electrics on left in driver's Test box V.A.G 1598/31
footwell, position 4 Contact Socket
16 65
- Eliminate open circuit in wiring/short circuit if necessary.
If no fault is found:
- Replace Fuel pump relay -J17-.
- Reconnect engine control module.
Checking voltage supply to components powered by fuel pump relay
- Take out fuses S228, S232 and S234 (positions 28, 32 and 34) in fuse box.
- Start final control diagnosis and actuate EVAP canister purge regulator valve -N80-.
NOTE: This step is designed to energize the fuel pump relay. It remains energized for one minute. Each time the next control element (e.g. secondary air injection solenoid valve -N112-) is selected before the above period has elapsed, the one-minute energization time recommences. The engine must be started briefly to initiate final control
diagnosis again.
- Connect multimeter for voltage measurement to Ground and to one contact of following fuses in fuse box.
Fuse Specification at one of the contacts
S228 approx. battery voltage
S232 approx. battery voltage
S234 approx. battery voltage
If readings do not match specifications:
- Repeat test at other contact of fuse socket.
If readings still do not match specifications:
- Check wiring.
If no fault is found:
- Replace Fuel pump relay -J17-.
- Re-insert fuses.