With Manufacturer's Scan Tool
Fuel Injectors, Checking
Special tools and equipment
- VAG1551 Scan Tool (ST) or VAG1552 mobile scan tool with VAG1551/3 adapter cable
- VAG1598/22 test box
- Multimeter (Fluke 83 or equivalent)
- Diode test lamp VAG1527
- VW1594 adapter set
- Wiring diagram
Test requirements
- Fuses 28 and 32 OK
- Engine speed sensor OK. Engine Speed (RPM) Sensor, Checking
- Battery (B+) voltage at least 11.5 V
- Fuel pump relay OK
Test sequence
WARNING! Fuel system is under pressure! Before opening the system place a cloth around the connection. Then release pressure by carefully loosening the connection.
- First check activation of fuel injectors via output Diagnostic Test Mode (DTM). [1][2]Output Diagnostic Test Mode (DTM), (Function 03)
If one or more fuel injectors do not click:
Checking activation and voltage supply
If fuel injectors of cylinder No.2 or 3 do not click:
- Remove intake manifold upper section. Service and Repair
NOTE: Seal the intake ports in the in take manifold lower section or in cylinder head with a clean cloth.
- Disconnect fuel injector harness connector of cylinder No.2 and 3.
- Connect VAG1527B voltage tester using auxiliary cables from VW1594 to harness connector terminals of cylinder 3.
- Operate starter and check voltage supply for No.3 cylinder fuel injector.
LED must flicker.
- Repeat check at fuel injector harness connector for No.2 cylinder.
If fuel injectors of cylinder No.1 or 4 do not click:
- Separate fuel injector harness connector of cylinder No.1 and 4.
- Connect VAG1527B voltage tester using aux. cables from VW1594 to harness connector terminals of cylinder 1.
- Operate starter and check voltage supply for No.1 cylinder fuel injector.
LED must flicker.
- Repeat check at fuel injector harness connector for No.4 cylinder.
- Switch ignition off.
If the LED does not flicker on any cylinder:
- Connect diode test lamp to cylinder 4 fuel injector harness connector, terminal -1- and Ground (GND).
- Initiate output Diagnostic Test Mode (DTM) again and activate No.4 cylinder fuel injector.
LED must light up.
- Repeat check at fuel injector harness connectors for cylinders 3-1.
If the LED does not light up:
- Switch ignition off.
- Check wire between 2-pin harness connector terminal -1- and Fuel Pump (FP) relay -J17- for open circuit according to wiring diagram.
Wire resistance: max. 1.5 ohms
If the LED flickers on one or several cylinders:
- Remove wiper arms and plenum chamber cover.
- Connect VAG1598/22 test box to control module wiring harness.
- Check wiring between test box and fuel injector 2-pin harness connectors for open circuit according to wiring diagram.
- Injector 1: terminal -2- + socket 73
- Injector 2: terminal -2- + socket 80
- Injector 3: terminal -2- + socket 58
- Injector 4: terminal -2- + socket 65
- Wire resistance: max.1.5 ohms
- Additionally, check wires for short to one another.
Specified value: Infinity ohms
- Check wiring for open circuit between fuel injectors (terminal -1-) according to wiring diagram.
Wire resistance: max. 1.5 ohms
- If no malfunction is found in the activation or voltage supply, check resistance of fuel injectors.
Checking resistance of fuel injectors
- Check resistance of fuel injectors between terminals.
Specified value: 14.0-18.0 ohms
NOTE: The resistance figures are valid for approx. 20°C. At higher temperatures the resistance figures will increase.
If the specified value is not obtained
:
- Replace faulty fuel injector See "Intake Manifold Lower Section, Disassembling and Assembling", item 7. Service and Repair
Pay attention to the following when installing the fuel injector:
- Replace O-rings on all fuel injectors and lightly moisten with clean engine oil.
- Insert fuel injectors vertically and in the correct position into the fuel rail and secure using retaining clips.
- Fit fuel rail with fuel injectors installed and secured on intake manifold lower section and press in evenly.
- Check DTC memory. If necessary, repair any malfunctions and erase DTC memory.
Reading Diagnostic Trouble Codes
Clearing Diagnostic Trouble Codes
- Display readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If DTC memory has been erased or the Engine Control Module (ECM) was disconnected from permanent battery (B+) voltage, the readiness code must be generated again. Monitors, Trips, Drive Cycles and Readiness Codes