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Forum namePerformance/Engine
Topic subjectcheck engine PO172 code
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=123013
123013, check engine PO172 code
Posted by Snail_GS, Jun-10-06 01:24 PM
Had this code for a few days now, car is running rich and when coming to a stop the car either idles really low or stalls. I'm thinking fuel pressure regulator, any idea folks?

PS PO172 is my only code.
123014, RE: check engine PO172 code
Posted by turbo8u, Jun-10-06 11:14 PM
ok this is what you got:

first of all, reset it. see if it, or any other one, comes back.

PO172 52 Fuel System Rich MAP sensor output / Injector / Fuel pressure / Intake air leaks / Heated oxygen sensor / Adjust S-AFC

check accordingly
123015, RE: check engine PO172 code
Posted by Snail_GS, Jun-11-06 02:45 AM
I have cleared the code before came back the next day. Dont have a safc guess I will check map sensor also. btw where do you guys get filters for your missinglink, missed placed all the ones I had not too long ago.
123016, RE: check engine PO172 code
Posted by baxsom, Jun-11-06 11:05 AM
you can use the foamy earplugs or even cigarette butts. i had a piece of an eggcrate mattress in mine working fine for a while.
123017, RE: check engine PO172 code
Posted by turbo8u, Jun-11-06 07:19 PM
Originally posted by turbo8u
ok this is what you got: first of all, reset it. see if it, or any other one, comes back. PO172 52 Fuel System Rich MAP sensor output / Injector / Fuel pressure / Intake air leaks / Heated oxygen sensor / Adjust S-AFC check accordingly


do you have a datalogger? hows the car idle? do you have a fuel pressure gauge, and if so whats the pressure? with the datalogger youll be able to see the oxygen sensor cycle in open loop, if it sticks at any certain voltage for a long time, its probably faulty.

also if you have an ohmmeter it wouldnt hurt to check the map sensors resistance and see if its in spec (use the tech manual)

just tryin to help
123018, RE: check engine PO172 code
Posted by Snail_GS, Jun-12-06 06:33 AM
thanks for the info turbo8u, I myself dont have a datalogger but a buddy of mine does.
123019, RE: check engine PO172 code
Posted by ner947, Jun-12-06 06:40 AM
Originally posted by turbo8u
check the map sensors resistance


I've never done that before... why would you want to send current from an ohm meter through that sensor? Maybe there is a way to check the vitality of that sensor through measuring the resistance that I don't know about. As far as I know, the easiest way to check if it's working is to get a datalogger and watch the output or tap the output wire with a voltmeter and check to see you get ~4.5 volts with the engine stopped and a much lower reading while it is running at idle.
123020, RE: check engine PO172 code
Posted by turbo8u, Jun-12-06 04:14 PM
Originally posted by ner947
Originally posted by turbo8u check the map sensors resistance
I've never done that before... why would you want to send current from an ohm meter through that sensor?


You're not supposed to check resistance with any current flowing. Typically an ohmmeter has a 5-10amp fuse and it will pop. No current flowing when youre using and ohmmeter, no power. Just checks for continuity, excessive resistance, and shorts, etc.

123021, RE: check engine PO172 code
Posted by Snail_GS, Jun-13-06 11:27 AM
ok looks like my idle problem was caused of the missinglink element filter fell off. car idles fine so far thanks for the info guys