cantwin1

Hi all,

Got a check light on the dash yesterday. Hooked up the SCT, P2197.
https://mustangforums.com/m_3407983/tm.htm
Used search found that. I found my maf sensor fitting a bit loose, tightened
that, reset code, drove for about a half hour, no problem. Parked. Drove a
couple hours later got same code. Today, took off the CAI, tightened everything
up, reset code, drove, no problem. Parked for a bit, started and got same code.

Found this:
P2197
Lack of HO2S-21 Switch, Sensor Indicates Lean
Detailed Description
A heated oxygen sensor (HO2S) indicating lean at the end of a test is trying to correct for an over-rich condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time.
Possible causes :-
Electrical:
# Short to VPWR in the harness or HO2S.
# Water in the harness connector.
# Open/shorted HO2S circuit.
# Corrosion or poor mating terminals and wiring.
# Damaged HO2S.
# Damaged powertrain control module (PCM).
Fuel System:
# Excessive fuel pressure.
# Leaking/contaminated fuel injectors.
# Leaking fuel pressure regulator.
# Low fuel pressure or running out of fuel.
# Vapor recovery system.
Induction System:
# Air leaks after the mass air flow (MAF) sensor.
# Vacuum Leaks.
# PCV system.
# Improperly seated engine oil dipstick.
EGR System:
# Leaking gasket.
# Stuck EGR valve.
# Leaking diaphragm or EVR.
Base Engine:
# Oil overfill.
# Cam Timing.
# Cylinder compression.
# Exhaust leaks before or near the HO2S(s).

I've got headers, CAI, and Bama tune. Had this setup for quite some time, no issues.
Any suggestions? Experience with this particular code? Suggestions on what to try
next?

Thanks!!

aircare84

Swap the O2 sensors side-to-side & see if you end up getting a P2196. If so, sounds like the O2 sensor had gone bad.
Also, If you've got O2 sensor extenders, I'd check the connections & make sure they are clean & tight.
I got a few P2196 codes after my header install, but usually after or during a hard rain. Swapped the sensors, cleaned the connections & haven't had a code since.

cantwin1

Thanks! Was looking for an easy...try this...type idea.
I extended the sensors myself, with wire and solder. We did have a good rain last week, possible water got into my electrical tape wrap. Will swap them and see what happens.

cantwin1

OK, just got back from about a 40 min. test drive after switching the 02 sensors. Stopped in a parking lot for about 10 min. to let it cool a bit. Trying to simulate the situation when the error code came back on the last two times. So far, so good, no error. Only thing I did was switch the sensors, cleaned the soot off of them, and blew some air thru the holes in the sides of them.

Will post back in a day or two with an update.