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2000 Jetta GLS Check Engine Code P1128: Causes, Fixes & Solutions

Model: 2000 Jetta GLS Fault Code: P1128 Posted: 2007-01-21 11:13

I own a 2000 Volkswagen Jetta GLS 2.0L 4-cylinder with 92,000 miles. The check engine light has been on since day one — I purchased the vehicle at 82,000 miles. Initially, after driving it for about 30 days, the check engine light activated. I took it to Advanced Auto Parts and received two codes: Cylinder 1 misfire and gas cap unsecured (which was confirmed as stolen). After replacing the gas cap and clearing the codes, I noticed the vehicle began to sputter specifically in 2nd and 3rd gears. It would run normally for about one to two minutes before returning to sputtering. After completing flight school, I drove it from West Palm Beach, FL to Syracuse, NY. In New York, vehicles require an inspection to remain on the road — if the check engine light is on, it fails automatically. A mechanic inspected the spark plugs, which were in good condition, and performed a tune-up. Later, another shop scanned the vehicle and reported a 'Throttle Control Arm' issue. After clearing this code, it returned within a day. I then visited a third repair shop that diagnosed Code P11208 (P1128) — which relates to the Mass Air Flow (MAF) sensor control of air/fuel mixture. I replaced the fuel filter as a next step, but the sputtering persisted in 2nd and 3rd gears. I’ve since researched potential causes including MAF sensors, catalytic converters, oxygen sensors, and vacuum leaks. I purchased an OEM Mass Air Flow sensor from eBay, but after installation, the car ran poorly and stalled immediately — no signs of vacuum leaks were detected. I currently have limited funds to invest in further repairs. I am planning to drive this vehicle to Texas in two weeks and need a reliable fix for Code P1128. Can anyone provide guidance on what components should be checked or replaced to resolve this issue? Any help would be greatly appreciated.

Related fault codes
P1128
Comments (2)
Anonymous 2007-08-11 21:12

I experienced the same issue — bought my 2000 Jetta GLS about two weeks ago for $100. It sputtered badly. We replaced spark plug wires, spark plugs, mass air flow sensor, and coolant temperature sensor. The sputtering stopped after installing the MAF sensor, but then it passed emissions testing before the check engine light came back on. A scan revealed trouble code P1128 — which relates to the Mass Air Flow sensor's control of air/fuel mixture. What parts should I inspect or replace for this code? Thanks.

Anonymous 2007-08-13 06:50

Code P1128 in a 2000 Jetta GLS is typically linked to the Mass Air Flow sensor or its associated electronic throttle control system. The most likely cause is either a faulty MAF sensor or an issue with the electronic throttle body. A proper diagnosis using an OBD-II scanner and possibly a throttle body reset or replacement may be required. Consider checking for sensor signal errors, wiring issues, or vacuum leaks before replacing parts.