I have a 06 2.0 SC. I have 3 error codes that are popping up.

P0036 = Heater Control Circuit Sensor 7
P0135 = O2 Sensor Heater Cicuit Malfunction (Bank 1 Sensor 1)
P0141 = O2 Sensor Heater Cicuit Malfunction (Bank 1 Sensor 2)

A few months ago I have just the P0135 code and replace the sensor. Shortly after all my troubles the check engine light returned. Can anybody help me locate the sensors mentioned above to guarantee I replace the correct parts. And if anyone knows what to do about the P0036 code that would be very helpful. Thanks

 

The sensors will be in the downpipe on your car. Check the wiring because since you are getting all 3 codes and a new sensor didn't fix the problem, you might have some bare spots on the wires that's causing the issue

 

Most likey a corroded or broken heater ground or power wire....just had one today with a corroded wire two inches up from plug

 

So I need to look for a sensor "in" the down pipe? Do you kow where I can find a photo or diagram of that?

 

Not trying to be a dick but why not just crawl under the car and look at the downpipe? There will be 2 things plugged into the downpipe. The one closest to the motor is sensor 1, the other one is sensor 2

 

Thank you

 

One other question. What is the difference between an upstream and a downstream sensor? Not the location but the functionality of them. I am trying to buy parts but can't seem to see why one costs more than the other. thanks for any help.

 

Upstream is what the computer reads to determine the changes it needs to make in fueling. Basically tells the computer if the car is running rich or lean and it figures out how to compensate for it based off that reading. The downstream sensor is only there to determine if the catalytic converter is functioning properly. Downstream also gives a rough temperature reading of the exhaust after it goes through the cat

 

I know this is like 8 years late, but what would the normal voltage to the o2 sensors look like?

From what I’ve read, they should be between .1 and .9V. I don’t really know much about oxygen sensors or how they work but I’m trying to learn. Is this typical for O2 sensor voltage?

 

Yes this is typical behaviour of a working O2 sensor. It oscillates and as long as it stays within range, it's working. The O2 sensors tell your computer the exhaust mixture and if it catches signals of oxygen in your exhaust, it means that the gasoline isn't burning correctly (rich/lean).

Quick video with more detail: