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P0171 - System Too Lean - Bank 1

1064 Views 8 Replies 5 Participants Last post by  davidtranlds
Hi everyone,

Name's David from the land down under.

I've recently purchased a used Holden Cruze 2012 SRi-V JH Series II, 1.4L turbo petrol.

I had a check engine light come on, but after some driving, it went away.

Day or two later, it came on again and now it's permanently on whilst I drive.
I had also refueled with Unleaded 95 (manual says to use 91 but 95 also worked for a little extra performance), not sure if the light returned after or before I used the 95, but recently received my OBDII reader and that's how I got the code above.

I noticed the STFT would be around the -3% to +4% when idling, but LTFT would be around +30%.
When accelerating and driving/cruising, they'll both float around the -5% to +5%, sometimes going up to +10% depending on when I'm accelerating or decelerating heavily, or something, too random for my basic knowledge to pinpoint.

I do notice when I come almost to a stop, STFT jumps to around +15% then drops back down again once I've stopped, or start accelerating again.

I did some basic troubleshooting, tried the water spray method but I think it was too windy or something.
Anyways, tried the purge valve and when the car's on idling, there's suction, so I believe that's one problem.

But based on the above STFT and LTFT details, could there be anything else?

1 - 1 of 9 Posts
Check hose between the air filter and the throttle body for cracks. Lazy people will bend that hose when checking or changing the air filter. This will allow in unmetered air causing a lean condition.
1 - 1 of 9 Posts