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Old 06-24-2001, 12:29 PM   #1
Scooby Newbie
Member#: 1442
Join Date: May 2000
Location: Baltimore, MD USA
1999 2.5 RS
Aspen White

Question MY 99 CE Light: Fuel Trim Error

Alrighty, I have a custom intake on a MY99 RS. It's been on the car since late winter. A couple weeks ago, I got my first check engine light. Took it to the dealership, they checked it out and said there was a fuel trim error. "Nothing to worry about", and reset the light. About a week later, the light came back. This time, I took it to a local garage where the owner owns a couple soobs. He got the same message on the OBD2. He told me the manual lists several pages of tests to be done - BIG $$. Apparently, one bank of cylinders never has the fuel/air mixture altered. I decided to take this question to the experts before I spend lots of cash on tests. Anyone have any suggestions?

Dan Z.
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Old 06-25-2001, 07:39 AM   #2
Scooby Newbie
Member#: 1442
Join Date: May 2000
Location: Baltimore, MD USA
1999 2.5 RS
Aspen White


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Old 06-25-2001, 08:33 AM   #3
Scooby Specialist
Member#: 689
Join Date: Dec 1999
Chapter/Region: NESIC
Location: Lebanon, NH, USA
2005 Outback 2.5 XT
Champagne Gold Opal


The only time I got that code was when I was messing around with my fuel system and other exhaust-related components. Thinking nothing of it, I cleared that code along with numerous misfire codes.

My observation is that the ECU sets up a long-term fuel trim on a rolling average, and takes between 1-3 hours or driving to compensate for big changes in the emission control system. Although, I usually get a batch of misfire codes, and can't duplicate that one time I got the fuel trim code.

I can only guess at why you got this code:
1. Your catalytic convertor failed.
2. You filled up with a very bad tank of gas.
3. Your fuel injectors are failing or leaking.
4. You have a leak in the EGR or elsewhere in the emissions control system.
5. You have an exhaust leak somewhere between the engine and the catalytic convertor.

Did the dealership look the car over?

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