Tip & How-To about Chevrolet Impala

How to resolve a mass air flow sensor code : ALL vehicles.

How to resolve a DTC , p0171, or p0174 code. This code usually does not appear on your vehicles dash, but rather a "check engine" light will display.
If you have an OBD II reader,( some auto parts centers will allow you to borrow theirs) plug it into your vehicle (usually under the passenger side dash) and pull the code.
This code usually means that your MAF ( mass air flow sensor) is reading the air/fuel mixture and senses a problem or may be dirty.
There are a couple of things you will need to solve this problem.
- You will need a can of mass air flow sensor cleaner, and a screwdriver.
Step one : Depending on which vehicle you have you must locate the MAF.
It is usually inline on the air cleaner intake or air "box".
Step two : Unplug the connector from the MAF, and loosen the hose clamp holding it tight.
Step three : Pull the MAF out and be VERY careful DO NOT drop it !
Step four : Make sure you are in a well ventilated area, and place the MAF gently onto a clean rag or absorbent towel, spray the inside of the MAF that looks like a honey comb, and make sure you DO NOT touch the small sensor wire !
Step five : DO NOT dry off the MAF it will dry quickly, re-assemble and test out your vehicle, we usually hear people tell us they notice a difference right away in the performance of their vehicle.

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I have a 1997 Chevy Blazer with the 4.3 engine. The Service Engine light keeps coming on. I scanned the codes and replaced the O2 sensor just before the catalytic converter. The light is still coming on and the following codes are coming up: P0140 01/06, P0146 02/06, P0140 pd 03/06, P0146 pd 04/06, P0171 pd 05/06, P0174 pd 06/06. What do these mean and what do I need to do to fix the problem? Thanks, Craig

P0146 pd means pending code
Pending codes and DTCs? Posted on November 12, 2010 by fcrmaster
When reading codes from your vehicle the fault code reader may show them as pending codes or normal Diagnostic Trouble Codes (DTC).
Pending codes (also known as continuous monitor codes) will be registered when an intermittent fault occurs. If that fault does not happen again after x number of start/stop cycles, the ECU will erase the code from memory. If the fault is persistent it becomes a DTC.
If you have read pending codes it is advisable to check the codes again after a week or so. If there is no apparent problem with the vehicle it is safe to erase the codes too and check back. But always make a note of any fault codes with the date and mileage of a vehicle.
If the codes read include a DTC then you need to investigate further. This you can either do yourself or advise your garage. If, again, you don't see an apparent problem (depending n the severity of the code) with the vehicle you can note the codes down and erase them. Then check again after a week or a few days depending on how often the vehicle gets used. If a repair has been made (previous owner) the DTC may just not have been reset after the repair.
The other numbers behind the code 01/06 , 02/06, 03/06 , 05/06 ,04/06 These don't mean anything . cheap code reader .
DTC P0140 HO2S Circuit Insufficient Activity Sensor 2
DTC P0146 HO2S Circuit Insufficient Activity Bank 1 Sensor 3
DTC P0171 Fuel Trim System Lean Bank 1
DTC P0174 Fuel Trim System Lean Bank 2
Sorry but this is something you should take to a qualified repair shop that has a diagnostic tool that can view sensor scan data.
Causes of lean condition trouble codes P0171 P0174 GM 5 3L
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Ford windstar check engine light comes on after stopping when starting to get moving again shows p0171 & p0174 codes why??

P0171 indicates a lean condition. The most common cause of this is a defective mass air flow sensor. Also check if any vacuum leaks. P0174 OBD-II Trouble Code


Technical Description

System Too Lean (Bank 2)


What does that mean?

Basically this means that an oxygen sensor in bank 2 detected a lean condition (too much oxygen in the exhaust.

Note: This DTC is very similar to P0171, and in fact your vehicle may show both codes at the same time.

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Thanks.


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check engine light on

Generally when these codes appear it is due to insufficient fuel pressure. Test your fuel pump to ensure it is within specs. Have you changed your fuel filter?
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