Checking EGR valve — VW

AGD AHG AKU ASX
Special tools, workshop equipment, test and measuring appliances and auxiliary items required

V.A.G 1526 A Hand multimeter or multimeter V.A.G 1715
V.A.G 1594 A Adapter set
V.A.G 1598/18 Test box
for 68-pin control unit
V.A.G 1598/22 Test box
for 80-pin control unit
V.A.G 1598/31 Test box
for 121-pin control unit
Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
Current flow diagram

Check conditions

Fuses must be OK.
The battery voltage must be at least 11.5 V.

Test sequence

Pull 2-pin connector off EGR valve (N18) -arrow-.

Measure resistance between valve contacts.
Specification:
Engine codes AGD, AHG:
52.5...62.5 ω
Engine codes AKU, ASX:
14.0...20.0 ω

Note:

At room temperature the resistance is in the area of the lower tolerance and when engine is at operating temperature in region of upper tolerance.

If the specification is not obtained:

Replace EGR valve (N18).

Checking voltage supply for EGR valve (N18)

Connect hand multimeter V.A.G 1526 with aux. cables from V.A.G 1594 to connector contact 1 and engine earth.
Switch on ignition.
Specification: min. 11.5 V
Switch off ignition.

If the specification is not obtained:

Engine code AGD (with 68 pin control unit)

Connect test box V.A.G 1598/18 to control unit wiring harness. The engine control unit -2- is not connected.

Check wiring for open circuit between test box and connector using current flow diagram.
Contact 1+ socket 68
Contact 2+ socket 25
Wire resistance: max. 1.5 ω

Engine codes AGD, AHG, AKU:

with 80-pin control unit

Connect test box V.A.G 1598/22 to control unit wiring harness.

Check wiring between test box and connector for open circuit according to current flow diagram.
Contact 1+ socket 2
Contact 1+ socket 28
Contact 2+ socket 29
Wire resistance: max. 1.5 ω

Engine codes AGD, AKU, ASX:

with 121-pin control unit

Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.

Note:

Gradual introduction of valves with new connector.

Vehicles with old connector shape

Check wiring between test box and connector for open circuit according to current flow diagram.
Contact 1+ socket 1
Contact 1+ socket 2
Contact 2+ socket 61
Wire resistance: max. 1.5 ω

Vehicles with new connector shape

Check wiring between test box and connector for open circuit according to current flow diagram.
Contact 1+ socket 1
Contact 1+ socket 2
Contact 2+ socket 61
Wire resistance: max. 1.5 ω

Continued for all engine codes

Additionally check wires for short to one another, to vehicle earth and to battery positive.
Specification: ∞ω
Additionally check the wiring for short to battery positive or earth.
Additionally check wires for short to one another.

If no fault is detected in the wiring:

Renew engine control unit:

=> Repair group 23; Renewing, coding and adapting engine control unit; Renewing engine control unit
4-cyl. Diesel engine, Mechanics
Renewing, coding and adapting engine control unit
Renewing engine control unit