Chevy / GM P0171 or P0174 System To Lean Bank 1 Bank 2

Рет қаралды 10,829

Күн бұрын

I'm going to go over some common issues causing the P0171 and P0174 error codes in Chevy and GM vehicles, indicating a system too lean in both Bank 1 and Bank 2. Under standing fuel trim numbers can aid greatly in get to the source of the problem.
We start by conducting a smoke test on the intake to detect any leaks. Next, we assess the condition and performance of the mass air flow sensor and fuel pressure test to ensure they meet specifications. Further inspections include the PCV valve and the brake booster, along with other critical components like fuel pressure regulator, that could lead to a lean-running engine.
Whether you're a DIY enthusiast looking to understand more about your vehicle or a professional mechanic honing your skills, this video provides step-by-step guidance on diagnosing and fixing lean engine problems and understanding fuel trim reading on a scanner.
#ChevyRepair #LeanBank1Bank2 #AutoRepair #CarMaintenance #DIYMechanic #P0171 #P0174 #FlatRateMechanic
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Пікірлер: 13

@FlatRateMechanic Ай бұрын

This is the smoke leak checker I got on Amazon amzn.to/4ccprqC. It works great!

@andrewfredrick7017 24 күн бұрын

this was very helpful thank you! i bought the smoke tester, it's great. found a tiny leak where the intake boot clamps to the throttle, but no change after that was tightened. did a water spray all over the intake manifold gaskets and no steam out of the exhaust. smoke tested the exhaust as well and nothing. my long term fuel trim is around 18% on both banks at low load or idle and drops to around 10% under medium throttle. i did notice my intake air temp was considerably off from actual air temperatures and very slow to respond to changes ( from sitting in a parking lot, hot start on a hot day, to diving down the highway at 55, it changed very slowly and never read the right temp, was always high by about 5-10%) new maf on the way, i think mine is original, 20yrs old, 264k on it. cleaning it didn't have any impact.

@stevemaltez4123 Ай бұрын

Excellent

@justinlong977 15 сағат бұрын

I have these codes and ltft numbers when I TAP and release the throttle the truck revs up and stays at the high rpm on its own for a second or two then settles.

@robertrazo57 2 күн бұрын

So if I accelerate and my bank 2 trim goes down from 20 to 0 does that indicate bad fuel pump?

@AbramDorny-xt2lm 3 ай бұрын

Thanks for posting the video. 2004 Yukon 5.3L threw a MAF sensor code, so I replaced with a Delphi MAF just this past week. Code cleared, and now I have 171 and 174. If I understand your comments, with more driving is it possible the fuel trim numbers settle out to be in spec and stops throwing those codes?

@tasaiyaxaypanya3140 2 ай бұрын

I got a 5.3 Silverado and just replaced Maf and getting the same code, did u figure it out?

@CHRISFREE84 29 күн бұрын

@@tasaiyaxaypanya3140Same thing did you find a fix

@ws2664 3 ай бұрын

You should have pulled up the data pid for the mass airflow sensor and see what the grams per second flow reading was, that might have told you something. Was that new sensor after market or dealer? great vid other wise.

@FlatRateMechanic 3 ай бұрын

We put a denso MAF - I've had pretty good luck with this brand. Wouldnt recommend after-market

@venacorchea 25 күн бұрын

I replaced the Maf sensor, the intake gasket, replaced a PCV valve and the tubing and there’s not any other leak, now I have a P0174 code. Should I have to replace the oxygen sensors? Help!!! I already spent $700 pus the parts.

@hotcamaro9145 10 күн бұрын

There's some decent info buried in here, but the terms and language being used to describe some of it is wrong. Examples... Fuel trim is almost NEVER zero Fuel trim at idle isn't terribly helpful for a lot - trims under load matter much, much more - especially long-term trims. Specific issues with the 2014-2018 high pressure fuel pump design causes fuel leaks directly into the valves which causes a "rich" condition. This will set the MIL and DTC's but the only way to diagnose the bad LTFT's is while actively driving the vehicle. "Within 5% of zero" should like have been described as "within a range of plus or minus 5%" as "5% of zero" is zero...

@FlatRateMechanic 7 күн бұрын

I'm grateful for your detailed explanation and corrections on the terminology regarding fuel trim. Your input helps improve the accuracy of the content shared.