The Impossible Lean and MAF Code...
04-05-2019, 08:21 PM
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The Impossible Lean and MAF Code...
To say I'm at my wits end with my car is an understatement, lol. I've dealt with many issues over the past couple of years, but the most recent ones have me utterly confused.
My car is an 09 Audi S5, and it currently has 106,000 Miles.
I've documented a lot of my issues/repairs here (including a carbon clean and self cleaning my injectors
https://www.audizine.com/forum/showt...Problems/page2
For the past several months I've dealt with the same codes popping up. At this point I see them every single day:
- MAF implausible signal
- Bank 1 too lean off idle
- Bank 2 too lean off idle
Recently I've smoke tested for vac leaks and found one from the intake hose to the throttle body- tightened it, but no improvement.
Today, I replaced my MAF with a brand new one. Took the car out and within 10-15 min the MAF single implausible code popped up again (it also triggers a parking break malfunction and ESP malfunction on my dash). Along with that, my fuel trims were heading in the direction of tripping lean codes:
- Adaptation (Idle) Bank 1, sensor 1: -4.78%
- Adaptation (Partial) Bank 1, sensor 1: 19.92%
- Adaptation (Idle) Bank 2, sensor 1: -4.88%
- Adaptation (Partial) Bank 2, sensor 1: 22.27%
I'm at a loss for what this could be. Injectors? HPFP's? Mystery vaccuum leak that I missed? ECU?
Any help is greatly appreciated. Happy to provide any more info needed. I could go on for pages about specific problems I've had and fixes I've tried, but I want to keep the initial post to essential information.
I have a VAG401 by XTool, and it's what I've been using to somewhat diagnose what's going on.
I've also noticed my upstream O2 sensor voltages are abnormally high under measuring block 032. They almost never drop below 1v. At idle they're 1.45v, and when driving I've seen them up to 5v (usually when letting off the gas).
My car is an 09 Audi S5, and it currently has 106,000 Miles.
I've documented a lot of my issues/repairs here (including a carbon clean and self cleaning my injectors
https://www.audizine.com/forum/showt...Problems/page2
For the past several months I've dealt with the same codes popping up. At this point I see them every single day:
- MAF implausible signal
- Bank 1 too lean off idle
- Bank 2 too lean off idle
Recently I've smoke tested for vac leaks and found one from the intake hose to the throttle body- tightened it, but no improvement.
Today, I replaced my MAF with a brand new one. Took the car out and within 10-15 min the MAF single implausible code popped up again (it also triggers a parking break malfunction and ESP malfunction on my dash). Along with that, my fuel trims were heading in the direction of tripping lean codes:
- Adaptation (Idle) Bank 1, sensor 1: -4.78%
- Adaptation (Partial) Bank 1, sensor 1: 19.92%
- Adaptation (Idle) Bank 2, sensor 1: -4.88%
- Adaptation (Partial) Bank 2, sensor 1: 22.27%
I'm at a loss for what this could be. Injectors? HPFP's? Mystery vaccuum leak that I missed? ECU?
Any help is greatly appreciated. Happy to provide any more info needed. I could go on for pages about specific problems I've had and fixes I've tried, but I want to keep the initial post to essential information.
I have a VAG401 by XTool, and it's what I've been using to somewhat diagnose what's going on.
I've also noticed my upstream O2 sensor voltages are abnormally high under measuring block 032. They almost never drop below 1v. At idle they're 1.45v, and when driving I've seen them up to 5v (usually when letting off the gas).
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