Fuel Pump Relay: Testing and Inspection
Fuel Pump (FP) Relay -J17- And Activation, Checking
Recommended special tools and equipment
- V.A.G 1526A multimeter
- V.A.G 1594A connector test kit
- V.A.G 1598/31 test box
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.
Test requirements:
- Battery voltage at least 12.5 V
- Ignition switched off.
Function test of Fuel Pump (FP) relay
- Remove driver-side storage compartment.
- Connect test box to wiring harness of Engine Control Module (ECM), ECM is not connected. Test Box, Connecting For Wiring and Component Test
- Bridge terminals 1 and 65 at test box using wires e.g. from V.A.G 1594 A adapter test kit.
- Switch ignition on.
- Fuel Pump (FP) relay (at position 4 of central electronics in driver's footwell, left) must trigger and Fuel Pump (FP) must run.
A. If Fuel Pump (FP) runs:
- Check voltage supply of Fuel Pump (FP) relay
- Checking activation of Fuel Pump (FP) relay
B. If 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 for voltage measurement as follows.
Central electronics in driver-side Measure to
footwell, left, position 4
Terminal
17 Ground (GND)
Specified value: approx. battery voltage
If specified value is not obtained:
- Replace central electronics.
- Connect multimeter for voltage measurement as follows.
Central electronics in driver-side Measure to
footwell, left, position 4
Terminal
19 Ground (GND)
- Switch ignition on.
- Specified value: approx. battery voltage
- Switch ignition off.
If specified value is not obtained:
- Check wire connections for open circuit according to wiring diagram.
- Specified value: Wire resistance max 1.5 Ohms
If specified values are obtained:
Checking activation of Fuel Pump (FP) relay
- Remove cable bridge
- Remove Fuel Pump (FP) relay.
- Connect test box to wiring harness of Engine Control Module (ECM), ECM is not connected. Test Box, Connecting For Wiring and Component Test
- Check the following wire connection for open circuit according to wiring diagram.
Central electronics in driver-side Test box Socket
footwell, left, position 4
Terminal
16 65
Specified value: Wire resistance max 1.5 Ohms
- Check the wire for short circuit to B+ and Ground (GND).
- Specified value:Infinite Ohms (no continuity)
- If necessary, repair wire connection.
If no malfunctions are detected:
- Replace Fuel Pump (FP) Relay -J17-. or
- Replace Engine Control Module (ECM).
Check voltage supply for Fuel Pump (FP) and components
- Remove fuses S228, S232, and S234 (positions 28, 32, and 34) from fuse holder.
- Connect multimeter for voltage measurement to Ground (GND) and to one terminal of the following fuses in the fuse holder.
- Operate starter briefly.
Circlip Specified value at one of the terminals
S228 approx. battery voltage
S232 approx. battery voltage
S234 approx. battery voltage
If specified values are not obtained:
- Repeat test at another terminal of fuse socket.
If specified values are not obtained again:
- Check wire connections for open circuit according to wiring diagram.
- Specified value: Wire resistance: max. 1.5 Ohms
If no malfunctions are detected:
- Replace Fuel Pump (FP) Relay -J17-.
- Re-insert the fuses.
Assembly is performed in reverse order of removal, note the following:
- Install driver side storage compartment.
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory see "Mode 3: Check DTC memory". Mode 3: Check DTC Memory
2. If necessary, erase DTC memory see "Mode 4: Reset/erase diagnostic data". Mode 4: Reset/Erase Diagnostic Data
3. Generate readiness code. Readiness Code, Generating
- End diagnosis and switch ignition off.