Hi Everyone,
I know this subject has covered over time, but not for SII. I am not sure if any other S2 has recieved this Check Code before. A few believe in the S1 area this a vacuum leak usually. Any new info.

I have:
BHR Coils ~50k (maybe time to change out)
HFC w/ 3" mp
RB intake
RB Race Exhaust
89k+ Miles
Track the care pretty frequently, but not much this year.

Havent felt any power loss, so I dont think its major problem. I has noticed a lot of back firing thought and idle isnt a lil lil rough.

 

Look for a vac leak...most likely thing for that code

Otherwise it could be a lot of things....injector, fuel supply etc....

 

I haven't popped the hood yet, but thanks for info.
Do you think it could be exhaust leak? That has been mentioned before...

 

It would have to be before the o2 sensor...so unless you have had the manifold off...or you have a header that could have warped...less likely

Most common if the VFAD is removed (if you have an aftermarket intake)...is for the VFAD nipple plug to have fallen off.....

 

The Vfad is the first one I am going to check. I read that also. I havent touched the Header, so that should be unlikely.

THANKS!

 

Wouldn't a vacuum leak cause a rich A/F not a lean. As the PCM would just dump fuel to compensate for an unmetered leak.

 

if the PCM has to add too much fuel, then it is too lean.

this is from the S1 manual, System too lean

DETECTION CONDITION

• The PCM monitors the short term fuel trim (SHRTFT) and long term fuel trim (LONGFT) when under closed loop fuel control. If the fuel trim is more than the specification, the PCM determines that the system is too lean.

POSSIBLE CAUSE
• Front HO2S malfunction
• Excess air suction in intake-air system
• Leakage exhaust gas
• MAF sensor malfunction
• Fuel line pressure malfunction
• Fuel pump unit malfunction
• Leakage fuel
• Ignition system malfunction

– High-tension lead malfunction
– Incorrect power supply to ignition coil
– Ignition coil malfunction

• Insufficient compression

– Metering oil pump malfunction
– Engine oil condition malfunction
– Rised oil pressure
– Oil passage malfunction
– Engine malfunction

• Fuel injector malfunction
• PCM malfunction

 

I was under the impression the PCM monitored the A/F and sent corrections to the STFT, and LTFT as needed in order to obtain the desired A/F for the set condition.

Their is no STFT or LTFT tables for the PCM to compare to.