What happens??? DTC 172, 185 and 186 | Ford Explorer Forums - Serious Explorations

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What happens??? DTC 172, 185 and 186


October 27, 2009
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City, State
Year, Model & Trim Level
'93 Sport
I buy the X 93 and after 8 Km the check engine come on.

I clean the MAF, change the MAF housing for a 70 mm housing (bad idea) and then put again the original MAF housing an re-clean the MAF sensor, again, after 8 Km the engine check come on.

Trouble codes is 172, 185 and 186, what happens? I need change the MAF sensor? can I put a Ford Ranger 2.3 MAF sensor in the 70 mm MAF housing? or Ranger sensor in the X housing? :scratch:

All those codes basically point to an oxygen sensor that is giving a lean signal to the PCM. The thing that makes lean codes difficult to diagnose is that there are so many possible things that can make the engine run lean.

question: Are those all CM codes, or do you also get the 172 from the KEOR test (assuming that you've ran the KOER test)? If you haven't run the KOER test, yet, I would suggest you do that and see what codes you get. KOER codes can usually be considered "hard faults", which can make them a little easier to diagnose.

By the book, the first test with most O2 sensor/fuel control codes is to check fuel pressure.

From other symptoms (condition of exhaust and/or spark plugs), would you agree with the codes that the engine is running lean, or does the engine actually appear to be running rich (might point to a bad O2 sensor)? Some people consider an O2 sensor to be a maintenance item. If it has been a long time since the O2 sensor was last changed, you might consider changing it.

Any vacuum leaks (vacuum leaks can make the engine run lean)?

I put new spark plugs, new O2 sensors, all are CM codes, no vacuum leaks (I believe)

I haven't run the KOER test, today in the night...:salute: