Exhaust Gas Recirculation System, Checking

Refer to "On Board Diagnostic (OBD II), Readiness Code - Reading/Creating".

Exhaust Gas Recirculation System, Checking





Special tools, workshop equipment, test and measuring appliances and auxiliary items required:
- Fluke 83 Multimeter or equivalent
- VAG 1598/22 Test Box
- VW 1594 Adaptor kit
- VAG 1551/1552 Scan Tool with VAG 1551/3 adaptor cable
- Wiring diagram

Test sequence:
EGR (exhaust gas recirculation) function is checked via Function 04 (basic setting). Using this procedure, the EGR valve is pulsed every 10 seconds so the extreme values for Mass Air Flow can be read out in Measuring value block 003.

- Connect VAG 1551/1552
- Start engine and let idle
- Press 0 and 1 buttons to select Address Word 01 "Engine electronics"

Display will appear as shown

Rapid data transfer HELP
Select function XX

- Press 0 and 4 buttons to select Function 04 "Basic setting"
- Press 0 button to enter input

Display will appear as shown

Basic setting HELP
Input display group number XXX

- Press 0, 0 and 3 buttons to select "Display group 3"
- Press 0 button to enter input

Display will appear as shown

System in basic setting
820 rpm EGRn.active 500 mg/H 0%

Zone 2 display must fluctuate every 10 seconds between EGR active and EGRn.active.

Zone 3 and 4 displays must fluctuate within the following control range:

NOTE: If a constant value of 550 mg/H is displayed in display zone 3 it could be that the EGR valve is mechanically sticking or the Mass Air Flow sensor could be faulty. For the MAF sensor, check DTC memory to see if 00553 is stored.

Specification for display: EGRn. active (EGR not active)
- Specified range in display zone 3: 380 - 540 mg/lift
- Specified value in display zone 4: 0%

Specification for display: EGR active
- Specified range in display zone 3: 150 - 320 mg/lift
- Specified value in display zone 4: 99%

NOTE: The values in display zone 3 are pressure dependent and therefore altitude dependent. The figures given are for sea level. If because of altitude, the measured values deviate greatly, then check if there is a difference of at least 100 mg/c between the EGR active and EGRn. active displays in display zone 3.

If specifications not obtained:
- Check mechanical EGR valve
- Check vacuum hoses

Check EGR Vacuum Regulator Solenoid valve N18 as follows:
- Press -> button.
- Press 0 and 6 buttons to select Function 06 "End data transfer"
- Press 0 button to enter input
- Switch OFF ignition.





- Pull connector -1- off valve -2-.
- Measure resistance between valve terminals.
Specification: 14 to 18 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 at operating temperature in the upper tolerance range.

If specification obtained:
- Switch ON ignition.





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

If specification not obtained:
- Switch OFF ignition.





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

Terminal 1 + sockets 2 + 28
Terminal 2 + socket 29
Wire resistance: max. 1.5 Ohms

- Also check wires for shorting to one another, to vehicle Ground and Battery positive.
Specification: Infinite Ohms

If wiring OK:
- Replace Engine Control Module J248
- Check DTC memory and if necessary create Readiness code.

NOTE: If DTC memory has been erased, the Readiness code must be created. Refer to "On Board Diagnostic (OBD II), Readiness Code - Reading/Creating". Testing and Inspection