Jetta GL Wagon L4-1.9L DSL Turbo (ALH) (2002)
^
Apply vacuum and make sure that air flap arrow- opens and closes
freely.
If flap does not open and close freely:
^
Replace EGR valve / flap.
6.
MAF sensor and EGR valve including solenoid valve, checking
^
Check correct function of MAF sensor and EGR valve including solenoid valve (see Repair Group for procedure and operation ranges).
Tip:
Since both systems work closely together, if one system malfunctions it will directly affect the function of the other. Therefore it is important to follow
the procedure carefully.
^
In addition, the MAF sensor must be full-load tested. See Repair Group 01, On-Board Diagnostic (OBD).
If MAF sensor readings are out of tolerance (even if no MIL ON condition or DTC is present), before replacing any parts (MAF sensor, -G70- or EGR
solenoid valve -N18-):
^
Ensure wiring is OK and electrical connections are clean and functioning properly.
If wiring is OK and electrical connections are clean and functioning properly.
^
Replace MAF sensor.
Tip:
For manufacturer defect only: Claim MAF sensor repair/replacement under applicable warranty.
If MAF sensor failed full-load test, and after replacement of MAF sensor full-load value still cannot be attained:
^
Check turbocharger (see appropriate Repair Group).
7.
Crankcase ventilation system, checking
^
Inspect and verify that it is functioning to OEM specifications.
8.
Engine oil level, checking
^
Check and adjust to proper level if necessary. DO NOT overfill!
9.
Fuel quality, checking
^
If condition occurred suddenly, fuel quality may be inferior.
If fuel is suspected to be of poor quality:
^
Drain and refill fuel with known good quality fuel.
10.
Carbon build-up, checking