i have a 2002 s2k i just put a new motor in. Everything is pretty solid except i have a CEL P0135. heater circuit malfunction. I replaced the sensor and that didnt work so according to alldata i need to go back and start testing wires with a volt meter.

my biggest concern though is limp mode. my car is running SUPER rich. like 8mpg. and it keeps going into limp mode almost every time i drive it.

so is the sensor CEL the issue here or is it something im not seeing.

the car has NO OTHER symptoms besides running rich and the one CEL

 

Oh and I'm attempting to get a hold on a reader so i can read the codes when it goes into limp mode

 

IMO: Yes.
The primary O2 sensor is telling the ECU what to do in regard to mixture etc.
(So is the sec. O2, MAP sensor, throttle position sensor etc.., some are more important than others I guess)

Without proper data / missing data the ECU is clueless.

 

Ok so i read it in limp mode and it is showing up as a MAP sensor ?

any thoughts ?

Summary:

-MAP Sensor beyond electrical range
-Heater Circuit Malfunction in the upstream sensor
- Limp mode everytime i drive it.
- getting 8 mpg

 

check your MAP sensor....