p0171 & p0174
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p0171 & p0174
This codes pop up(p0171 and po174). The long term fuel trim is reading +28% in idle. I have checked all the vaccum lines and the intake it seem ok. I'm reading good signal from the mass flow sensor according to haynes book.
When i'm monitoring the O2 upstream sensors bank 1 and bank 2, the oscillating waveform in idle voltage transitions from near minimum (0.1 v) to near maximum (0.80v).That's a good signal, but when I press the brakes than the signal drop flat 0 volts and the short term fuel trim goes high to +25 %.
Is this normal or it's a problems with the brake booster causing a vacuum leak?
any advice would help
Thanks
When i'm monitoring the O2 upstream sensors bank 1 and bank 2, the oscillating waveform in idle voltage transitions from near minimum (0.1 v) to near maximum (0.80v).That's a good signal, but when I press the brakes than the signal drop flat 0 volts and the short term fuel trim goes high to +25 %.
Is this normal or it's a problems with the brake booster causing a vacuum leak?
any advice would help
Thanks
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