PDA

View Full Version : PO171 and PO401 codes Help please!



Carl333
07-22-2007, 07:46 AM
Newbie here. Read and read for hours here today.

Protege 1999 1.6 stock 70,000 miles Symptoms- Exhibiting poor acceleration, stuttering on the get go, doesn't seem to take its gas, choking. Does not stall and idles pretty smoothly.

Check engine light (for 2 years) on and the codes read as follows as of today:

PO171- bank one system too lean
PO401- EGR Flow Insufficient Dectected

This is what I have done so far.

PO401- Trying to reslove the PO401 problem, I removed the EGR and found that the valve was jammed in the closed position. After spraying several times with cleaners and manually openning and closing the valve, I finally freed it and is opening and closing freely without much resistance. Reinstalled. Above symptom is the same.

PO171- MAF Mass Airflow Sensor removed and sprayed for 10 seconds with contact cleaner. It didn't clean well. I still see some dirt but didn't want to touch the 2 wires in fear of breaking them.

Changed plugs 20,000 miles ago and looked at one plug and clean as a whistle.

Checked hoses for vacumn leaks and none that I can see. Air filter clean.

Going into the garage to test fuel pressure, maybe change fuel filter. Perhaps change o2 sensor 1st one before converter

1- Am I on the right track?
2- Did I miss anything?
3- What is a watergate actuator and how do I test if necessary?

Thank you for your responses.

Witchdoktor
07-22-2007, 08:31 AM
not to worry about a wastegate actuator, you don't have one. it's for opening a turbo.

p0171 if it isn't a vacuum leak is usually a bad maf or 1st o2 sensor. if you know someone locally you could switch sensors out to test or a scan tool to see voltage outputs would be better than throwing parts at the car. or you could just take it to the dealer.

Witchdoktor
07-22-2007, 08:34 AM
if it's the stock maf that would be my guess though.

red95_240sx
07-23-2007, 12:02 AM
Sounds like MAF problems.

Guilfordfall
08-04-2007, 12:28 AM
If the EGr is sticking, it wold be better to replace it then to clean it. The 1.6 don't go through alot of EGR valves like the 2.0L. So imo I would replace