Checking the Injection Valves — VW

Special tools, testing and measuring devices, etc. required

Test box V.A.G 1598/26
Hand-held multimeter V.A.G 1526 or multimeter V.A.G 1715
Measuring aids set V.A.G 1594
Diode testing lamp V.A.G 1527
Current flow diagram

Checking the activation

Testing conditions

Fuel pump relay OK, check:

=> Repair Group 20; Removing and fitting parts of fuel system; Checking fuel pump
Motronic Injection and Ignition System (4-Valve)
Removing and fitting parts of fuel system
Checking fuel pump

Engine speed sender OK => Page
24-68

Testing Procedure

Connect test box V.A.G 1598/26 => Page
01-71
.
Connect diode testing lamp V.A.G 1527 between Sockets 4 (blue) + 2 (red) on test box to check voltage supply of injection valves of cylinder 1 and 4.
Actuate starter.
The LED must flicker.
Connect diode testing lamp V.A.G 1527 between Sockets 13 (blue) + 2 (red) on test box to check voltage supply of injection valves of cylinder 2 and 3.
Actuate starter.
The LED must flicker.
Switch off ignition.

If the LED does not flicker:

Check voltage supply of Motronic control unit (J220) => Page
24-75
.
If no fault is found in the voltage supply of the control unit:
Replace Motronic control unit (J220)
=> Page
24-14
, Item
26
.

Check resistance of injection valves and wiring

Measure resistance of injection valves of cylinder 1 and 4 with multimeter and auxiliary cables from V.A.G 1594 between Sockets 4 (blue) + 2 (red) of test box:
Setpoint value: 7 - 8 ω

Measure resistance of injection valves of cylinder 2 and 3 with multimeter and auxiliary cables from V.A.G 1594 between Sockets 13 (blue) + 2 (red) of test box:
Setpoint value: 7 - 8 ω

If the setpoint values are not reached:

Remove the throttle valve control unit and the intermediate flange:

=> Repair Group 15; Removing and installing cylinder head; Removing and fitting the cylinder head cover
Motronic Injection and Ignition System (4-Valve)
Removing and installing cylinder head
Removing and fitting the cylinder head cover

Remove the throttle valve control unit and the intermediate flange:

=> Repair Group 15; Removing and installing cylinder head

Check the resistance of the injection valves between the contacts.
Setpoint value: 14...16 ω
Repeat the test on the injection valve cylinder 2...4.

If the setpoint value is not reached:

Replace the defective injection valve => Page
24-78
, Removing and fitting the injection valves.

If the setpoint values are reached:

Check wires between test box and plugs of injection valves for open circuit using current flow diagram.
Plug cyl. 1, Contact 2+Socket 4 (blue)
Plug cyl. 2, Contact 2+Socket 13 (blue)
Plug cyl. 3, Contact 2+Socket 13 (blue)
Plug cyl. 4, Contact 2+Socket 4 (blue)
Wire resistance: max. 1.5 ω
Also check wires for short circuit between each other.
Plug cyl. 1, Contact 2+Socket 13 (blue)
Plug cyl. 2, Contact 2+Socket 4 (blue)
Setpoint value: ∞ω
Check wires between test box and plugs of cylinder 1 - 4 for open circuit using current flow diagram.
Plug cyl. 1 - 4, Contact 1+Socket 2 (red)
Wire resistance: max. 1.5 ω
If the setpoints are not reached:
Check the cable connections according the current flow diagram:

=> Current flow diagrams, Electrical fault finding and Fitting locations

Disconnect test box V.A.G 1598/26 => Page
01-71
, Connecting test box V.A.G 1598, Disconnecting test box.

Check spraying pattern and for leaks

Warning!
Fuel system is under pressure! Before opening the system, place a cleaning cloth around the connection point. Then reduce the pressure by carefully opening the connection point.
Special tools, testing and measuring devices, etc. required

Test box V.A.G 1598/26
Measuring aids set V.A.G 1594
Tester for injection capacity V.A.G 1602
Remote control V.A.G 1348/3A with adapter cable V.A.G 1348/3-2

Test condition

Actuation of injection valves OK, check => Page
24-80
Test box V.A.G 1598/26 is connected => Page
01-71

Testing Procedure

Remove entire injection valve manifold with injection valves
=>Page
24-78
, Removing and fitting injection valves.

Reconnect injection valve manifold to fuel lines and insert injection valves in measuring device V.A.G 1602.
Connect plugs of injection valves.

Important!
To prevent destruction of electronic components and Motronic control unit, the following procedure must be followed exactly.
Pull red and blue plugs of test box off Motronic control unit.
Connect remote control V.A.G 1348/3A between Sockets 10 (red) and 8 (red) of test box with adapter cable V.A.G 1348/3-2 and auxiliary cables from measuring aids set V.A.G 1594.

Check for leaks

Actuate remote control V.A.G 1348/3A for approx. 10 seconds.

Check injection valves for leaks. No more than
2 drops/min
may exit.

Check spraying pattern

Disconnect 8-pin plug in protective sleeve on battery box.

Connect Contact 4 to Socket 8 (red) of test box with auxiliary cables from V.A.G 1594 .
Connect Socket 4 (blue) and 13 (blue) of test box with battery negative (31).
Actuate remote control V.A.G 1348/3A. Injection valves must spray in even pulses.

Note:

Replace the O-rings of the injection valves. When fitting the injection valves, make sure that the O-rings are not damaged.

To mount O-rings, moisten lightly with oil.
Disconnect test box V.A.G 1598/26 =>Page
01-71
, Connecting test box V.A.G 1598, Disconnecting test box.