Fuel Injectors, Checking

Fuel Injectors, Checking

Special tools and equipment
- VAG1598/31 test box
- VAG1526 multimeter or VAG1715 multimeter
- VAG1527B voltage tester
- VAG1594 connector test kit
- Wiring diagram

Test requirements







- All fuses must be OK.
- Engine speed (RPM) sensor must be OK, checking. Testing and Inspection
- Battery voltage must be at least 11.5 volts.
- Fuel Pump (FP) relay must be OK.

Test sequence
- First, test activation of the fuel injectors via output Diagnostic Test Mode (DTM). [1][2][3]Output Diagnostic Test Mode (DTM) (Function 03)

If one or more injectors do not click:

Check voltage supply.







- Disconnect 10-pin harness connector -1- to fuel injectors.


NOTE: The B+ supply for the fuel injectors is at connector terminals 7 and 8.







- Using adapter cables from VAG1594 connector test kit, connect multimeter once each between connector terminal 7 + vehicle Ground (GND) and connector terminal 8 + vehicle Ground (GND).
- Operate starter and the test voltage supply for fuel injectors.
Specification: 11 to 15 V

If specified values are not obtained:
- Check wire connection from terminal 7 and from terminal 8 to Fuel Pump (FP) relay according to wiring diagram.

Checking activation







- Using adapter cables from the VAG1594 connector test kit, connect VAG1527 voltage tester to disconnected 10-pin connector between terminal 1 + 7 for activation of fuel injector, cyl. 1.
- Operate starter and then test voltage supply for fuel injector of cylinder 1. LED must flicker
- Repeat test at fuel injectors 2 through 6
terminal 2 + 7 for activation of fuel injector, cyl. 2
terminal 3 + 7 for activation of fuel injector, cyl. 3
terminal 4 + 7 for activation of fuel injector, cyl. 4
terminal 5 + 7 for activation of fuel injector, cyl. 5
terminal 6+ 7 for activation of fuel injector, cyl. 6

If LED does not flicker:
- Switch ignition off.







- Connect VAG1598/31 test box to control module wiring harness. Engine Control Module (ECM) is not connected.







- Using adapter cables from VAG1594 connector test kit, connect multimeter for resistance measurement between test box and 10-pin connector:
fuel injector 1: Terminal 1 + socket 96
fuel injector 2: Terminal 2 + socket 112
fuel injector 3: Terminal 3 + socket 88
fuel injector 4: Terminal 4 + socket 113
fuel injector 5: Terminal 5 + socket 97
fuel injector 6: Terminal 6 + socket 89

Wire resistance: max: 1.5 Ohms

- Also check wires for short circuit to each other. Specification: Infinity Ohms

If no malfunctions are found in wires:







- Perform resistance measurement at 10-pin connector to fuel injectors once each between:

Connector terminals 1 + 7
Connector terminals 2 + 7
Connector terminals 3 + 7
Connector terminals 4 + 7
Connector terminals 5 + 7
and connector terminals 6+ 7.

Specification: 13 to 19 Ohms (at 20 °C).

If one or more specified value(s) are not obtained:
- Check the appropriate wire and connector to fuel injector.
- Remove intake manifold for this:


NOTE: Seal the intake channels in intake manifold and in cylinder head using a clean rag.

If no malfunctions are found in wires or connectors:


WARNING!
Fuel system is under pressure! Before opening system, place rags around the connection point. Then release pressure by carefully loosening connection.


- Replace faulty fuel injector.

Note the following when installing the fuel injectors:
- Replace O-rings on all fuel injectors and wet them slightly with clean motor oil.
- Insert fuel injectors into fuel rail perpendicular and in the right position, and secure them with retaining clips.
- Position fuel rail on cylinder head using secured fuel injectors and apply uniform pressure to press it in.
- The connectors must audibly engage on valves when attached.

After successful repair:
- Read readiness code. If DTC memory was erased or the Engine Control Module (ECM) was disconnected from the continuous B+ supply, the readiness code must be re-generated. Monitors, Trips, Drive Cycles and Readiness Codes Monitors, Trips, Drive Cycles and Readiness Codes