5 CEL codes
 

p0138 ; p2270 ; p0125 ; p2096.

i have been doing research, i know what all these codes mean individually but, all together maybes me believe something happened.

- im figuring p0138(rear o2 high voltage) and p2270(rear o2 stuck lean) could be resolved my replacing my rear sensor?

-p0125 Insufficient coolant temperature for closed loop fuel control.. i have not a clue what this is about..?!

-p02096 Target A/F feedback system too lean .. Could this also resolved by replacing the o2 sensor?

im nervous driving around if the car is running lean i dont want to damage the engine.

some background info on the car: 2004 MT 88k mi, ~7k on a new engine from mazda,
I just replaced my stock cat which blew out with another stock cat (stupid, but it was for sale for cheap)

any help would be pretty sweet! thanks guys

That's 3 different sensors (the 3rd is the coolant temp sensor likely not reporting accurate temp), but all related, and I think in the same wiring harness. I'd honestly look to see if something is chewing on your wiring harness, or any other source of shorting.

hmmm. its interesting you say that because i recently lost power to my cigarette lighter. i havent looked at fuses yet, but maybe its a coincidence or related.

if p02096 isnt a reading from an o2 sensor, where is it getting its lean code from.

do you think having replaced my cat without doing the computer/ sensor reset could have had any effect?

The O2 sensors are 4-wire sensors, a heater wire, a sensor wire, and the returning ground for each. The wires might not be all shorting, or all separated. Could have shielding stripped or melted, etc...

It only gets lean/rich from the front O2, but it's entirely possible for a wrong signal to come across. Since the reading is based on returning voltage, a steady voltage, or a voltage that won't go past a certain point (up or down), it can easily return a 'stuck' code (depending on which end or where they are stuck).

thats good knowledge thank you,
so do you think there is any relation between the oxygen sensor codes and the coolant code?
im aware of the issues the rx has with the coolant sensor

The coolant sensor issue is the coolant level sensor. The code you have is the ecu trigger that enters closed loop and lower fueling once the engine warms up. The ecu doesn't see the engine warming up within the specified time and throws the code. Typically it's a stuck open thermostat but with the other issues I think a wire harness problem is the root cause, and the engine is up to temp, the ecu just doesn't know it. Plug in an obd2 reader to see coolant temps and the are probably being mis-reported.

So while technically each code could be a hardware failed, the coincidence of 3 different sensors in the same harness reporting malfunctions that all relate to signals not moving like they should...

It's just far more likely that it's a problem in the harness.