PCM Code Help

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Sep 27, 2007 | 10:57 AM

11sec_C5Z51

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Racer

Joined: May 2006

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From: Houston TX

PCM Code Help

P0171 Fuel System Trim Lean Bank 1

What is setting this code? and which Bank is Bank 1?

Sep 27, 2007 | 03:30 PM

jirasvet

Burning Brakes

Joined: Jul 2007

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From: hill billy hell

Quote:

Originally Posted by 11sec_C5Z51

P0171 Fuel System Trim Lean Bank 1

What is setting this code? and which Bank is Bank 1?

PCM is detecting a lean condition from Bank 1 which is the driver side. This condition is determined from the switching Of O2 sensors from rich to lean. The PCM determines how much fuel to add or take away trough fuel trim value.
The long term fuel trim reading which use the O2s have a + or - range of up to 25%. If you are in the + range your system is lean. If you are in the - range your system is rich. For a DTC P0171 to set you have to be above +25%.
Most tuners shoot for +/- 5% for LTFT.
Is this the only code?
Not to jump to far a head but one cause could be an exhaust leak, bad O2, injector,or fuel system is not keeping up on high demand. ie fuel pump, fuel filter

Last edited by jirasvet; Sep 27, 2007 at 04:27 PM.

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