O2sensor troubles

[Kewopdecam]

My check engine light has been on for a while and it's a p1135 code which ended up being the o2 sensor. So I replaced both o2 sensors, had the check engine light turned off and in about 25 miles the code came back. I'm trying to figure out if the o2 sensors are broken or if they're being grounded somehow.

I took it to a mechanic and he told me my 4runner 2002 model is a California make and can only use o2 sensors from the dealer. I asked another mechanic about this and he said the guy was making stuff up. I'm just trying to figure out if I need to buy new o2 sensors or if the isssue lies elsewhere.


Right now I just got a full tank and I'm going to see if my mpg is normal. If so then I would think the o2 sensors are working fine.

Any tips on this dilemma? Thanks

 

[TheDurk]

You can buy Denso sensors anywhere (I recommend Amazon) and they will be identical to the dealer. Don't use Bosch, they don't play well. On a 2002, P1135 is the heater on the front A/F sensor. If you installed the correct Denso A/F sensor, check the heater resistance (see on-line FSM). If good, your problem is in the connectors or wiring.

http://www.ncttora.com/fsm/1996/SIL/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/di/eg5vzfe/cip1135.pdf

For more info, we have this thing called a search function. Put P1135 in there and see what happens...

 

[Kewopdecam]

Thanks for the reply. I bought a bosch and a denso part. It's a long story.

When I was told the 02 sensor was out I decided to replace both. The denso however happens to be the one the P1135 code was about. I bought the denso from amazon. This is the one I purchased

Amazon.com: Denso 234-9002 Oxygen Sensor (Air and Fuel Ratio Sensor): Automotive

Now, I'm not that car savy and I read that PDF but I don't really understand how to check the heater resistance. You think maybe the bosch part is causing the coding? Should I replace that with a denso part to keep all things even?

 

[TheDurk]

Thanks for the reply. I bought a bosch and a denso part. It's a long story.

When I was told the 02 sensor was out I decided to replace both. The denso however happens to be the one the P1135 code was about. I bought the denso from amazon. This is the one I purchased

Amazon.com: Denso 234-9002 Oxygen Sensor (Air and Fuel Ratio Sensor): Automotive

Now, I'm not that car savy and I read that PDF but I don't really understand how to check the heater resistance. You think maybe the bosch part is causing the coding? Should I replace that with a denso part to keep all things even?

No, I don't see how a Bosch in back could cause a heater fail code in front. If you see a P0420 in the future, suspect the Bosch.

The link I posted is the P1135 master page. For the resistance check, you have to follow the link in there to this page:http://www.ncttora.com/fsm/1996/SIL/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/sf5vzfe/afrs/insp.pdf

 

[Kewopdecam]

Okay, so I went to an atuoparts store and got my car scanned again just to make sure it was the same P1135 code. Apparently the code now is P0141 and the definition is

Heated oxygen sensor - Bank 1 Sensor 2

So, I'm thinking thats the other o2 sensor correct? Is this one on amazon what I need?

http://www.amazon.com/Denso-234-420...002&vehicleType=automotive&newCar=1&carId=001

I appreciate all the help.

 

[TheDurk]

Okay, so I went to an atuoparts store and got my car scanned again just to make sure it was the same P1135 code. Apparently the code now is P0141 and the definition is

Heated oxygen sensor - Bank 1 Sensor 2

So, I'm thinking thats the other o2 sensor correct? Is this one on amazon what I need?

http://www.amazon.com/Denso-234-420...002&vehicleType=automotive&newCar=1&carId=001

I appreciate all the help.

Yes, that is the rear (downstream) sensor, and NO!! that 234-4209 is a Universal type, which requires you to cut the plug off the old sensor and solder it on to bare wires on the new one. A 2002 4Runner takes a Denso 234-4261 Downstream O2 sensor (OE style). This means it comes with the correct plug already on. This one:

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=234-4261&x=16&y=20

I admit it costs $30 more but it doesn't sound like you are ready for the whole soldering wires thing. I am capable, but it's worth the extra money to me to have factory connections in a stressful place like an exhaust pipe.
Sounds like it didn't take long for the Bosch sensor to cause problems. Maybe you can take it back?

 

[Kewopdecam]

ah okay, good catch! So this means the Bosch one I had put in wasn't playing well with my 4Runner right?

I could probably put my old one back in since I never got a code for that, but I rather have two new ones. I'll order this and hopefully in a week I'll be posting how I have no more codes on my 4Runner

thanks