My grand daughter has a 2000 2.0 liter 5 speed Jetta with 47,000 miles. The check engine light came on and she called me. I put a scanner on and got one trouble code, P1128, which the Bently Manual identifies as "Long Term Fuel Trim Mult., Bank1 System too Lean". I cleared the code and it didn't return after a short ride. She indicated that the engine showed no change in the way it ran when the Check Engine Light came on. Can anyone tell me what this code means, and what the fix is. Any help would be appreciated.

 

IN MOST NEWER CARS THE CHECK ENG LIGHT HAS MORE TO DO WITH EMISSIONS THEN THE ENG.....I LOOKED THE CODE UP ON MY MITHELL SOFTWARE AND IF I WERE TO GUESS I WOULD SAY ITS A LEAK WITH YOUR SECONDARY AIR SYSTEM....... THIS WON'T CHANGE THE WAY THE CAR RUNS.......... DRIVE AND SEE IF IT COMES BACK..........IF IT DOES CHECK ALL YOUR VACUME LINES FOR LEAKS.... GOOD LUCK

 

Thanks for the information. After several days of driving the check engine light came on again. We will check the vacuum hoses and hope for a cheap and simple solution. I spoke with a local vw mechanic and he also thought the MAF is a possible suspect.

 

Bank 1 system refers to emissions, which could be O2 sensor, too. Shop around for that, in my case a dealership was cheaper

 

Thanks for this suggestion. The local guy I spoke to indicated that he doubted that it would be an o2 sensor because they would also send a second code which would be the cause of the o2 sensor signal. Either way, I'm waiting to find out since my son-in law has scheduled it into the shop.

 

It turns out it was the MAF, and because the car only has 40,000 miles on it VW covered the cost of parts and labor. Apparently they had a huge problem with MAF failures and have been replacing them by the thousands.

 

This is an interesting discussion. thank you for sharing
Good post. I appreciate it
Many thanks to ur post. I love it.
Hi guys, Im a newbie. Nice to join this forum.

 

I got this code, but how do I know if its the front sensor or the rear sensor?

 

This problem with the p1128 code occurs when you have a bad mass airflow sensor. p1128 code means Long Term Fuel B1 System Too Lean which happen to me once.I went to the dealer for its fix.

 

Lovely09 is right, I had the same trouble, and It was because the mass air flow wasn't working well