With Manufacturer's Scan Tool

Exhaust Gas Recirculation (EGR), checking





Special tools and equipment
^ Fluke 83 multimeter
^ VW 1594 Adaptor kit
^ VAG 1598/22 Test Box
^ VAG 1551/1552 Scan Tool with VAG 1551/3 adaptor cable
^ Wiring diagram

Test sequence

Note: The EGR return function is checked via Function 04 (Basic Setting). Through this procedure the valve for EGR is metered every 10 seconds, so that in measured value block 003 the extreme values for the EGR (air mass sensor) in display field 3 can be read.

- Connect VAG 1551/1552 Scan Tool:

- Start engine and let idle.
- Press 0 and 1 buttons to select Address word 01 "Engine electronics":





Indicated on display
- Press 0 and 4 buttons to select Function 04: "Basic setting".
- Press Q button to enter input.





Indicated on display
- Press 0, 0 and 3 buttons to select "Display group 3".
- Press Q button to enter input.





Indicated on display: (1 to 4 = Display zones)
Display in field 2 must fluctuate every 10 seconds between EGR active or EGR inactive.
Displays in display zones 3 and 4 must fluctuate within following control range:

Note: If a constant value of 550 mg/H is indicated in display zone 3, check Mass Air Flow sensor.

If EGR NOT active:
Specification display zone 3: 420 to 560 mg/stroke
Specification display zone 4: 0 to 5%

If EGR active:
Specification display zone 3: 170 to 340 mg/stroke
Specification display zone 4: 95 to 100%

If specifications not obtained:
- Check mechanical EGR valve.
- Check vacuum hoses.
- Check EGR Vacuum Regulator solenoid valve as follows:
- Press (Arrow) button.
- Press O and 6 buttons to select Function 06: "End transfer"
- Press Q button to enter input.
- Switch ignition off.





- Disconnect harness connector -1- from EGR valve -2-.
- Measure resistance across valve.
Specification: 14 to 20 Ohms

If specification not obtained:
- Replace EGR Vacuum Regulator solenoid valve -N18-.

Note: At room temperature, resistance lies in the the lower tolerance range and in the upper range at operating temperature.

If specification obtained:
- Switch ignition on.





- Measure supply voltage at valve connector terminal 1 and at engine Ground.
Specification: approximately battery voltage

If specification not obtained:
- Switch ignition off.





- Connect Test Box VAG 1598/22 to ECM wiring harness.
- Check wiring for open circuit between Test Box and harness connector using wiring diagram.

Up to MY 1999
^ Socket 1 + terminals 2 + 28
^ Socket 2 + terminals 29

From MY 2000
^ Socket 1 + terminals 1 + 2
^ Socket 2 + terminal 61
Wire resistance: 1.5 Maximum
- Check wires for short to one another, to vehicle Ground and to battery Positive (+).
Specification infinite Ohms

If wiring OK:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control