he guys I'm new i have a 99 monte z34. i am throwing these codes
P0102
VAF A low circuit
P0171

Can you please tell me what they are and the best fix.

Thanks in advance

 

P0102 - Mass or Volume Air Flow Circuit Low Input




Symptoms
- Engine stall
- Engine running rough
- Excessive fuel consumption
- Excessive smoke
- Engine Light ON (or Service Engine Soon Warning Light)
Possible causes
- Dirty mass air flow sensor
- Dirty mass air filter
- Mass air flow sensor harness is open or shorted
- Mass air flow sensor electrical circuit poor connection
- Intake air leaks
- Faulty mass air flow sensor
Tech notes
Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.

P0171 - System Too Lean Bank 1


Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
Possible causes
- Intake air leaks
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection
Tech notes
Dirty air filter of faulty air flow sensor are common causes for the P0171 code of the problem.

 

thanks a lot. ill try air filter first then move on to the maf. i thought the maf was the likely culprit but wanted to get opinions before spending the money

 

get a can of maf cleaner and see if that'll fix it

 

(I dont think the airfilter will change the codes)


Also try just unplugging the MAF sensor...and see if it runs any better or different....


I noticed you didnt post how its running or performing....

(I have the same vehicle)

 

it starts and runs fine. after about 5 minutes it will shudder under throttle and at a stop it will start losing rpm then stall

 

clean the maf with only maf cleaner, there's a chance it'll clear up the problem. Otherwise you may be forced to buy a new one

 

A quick check to see if it is the MF......unplug it and then start it up and see if it idles and stays running.....

If it fixes the shuttering and stahling......then you know the MAF is bad... If it is.....try cleaning it with MAF cleaner.....I ended up replaceing mine......as it was bad after 130,000 miles......

If that wasnt the cure...I would check your fuel pressure at the fuel rail...
Could be its time for a new fuel pump....