Check Engline Light, Code P0135

Hello

2003 Tacoma. Runs ok.

Got

$27 Ancel AD310 Classic Enhanced Universal OBD II Scanner Car Engine Fault Code Reader CAN Diagnostic Scan Tool, Read and Clear Error Codes for 1996 or Newer OBD2 Protocol Vehicle (Black)

this ODB II scanner. Only one code.

P0135
O2 Sensor Heater
Circuit Bank 1 Sensor
1

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Can anyone supply a checklist of what I should be doing to fix this?

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Replace O2 sensor (upper)

 

They usually run okay, but waste gas.

 

Thanks for response.

Some sites like this one say the problem is often a bad connector or fuse, and it can be a waste of money to spend

$143 Denso 234-9001 Upstream Air Fuel Ratio Oxygen Sensor with 10.6” 4-Wire Harness, for Auto Trans Equipped Vehicles

$135 on a new O2 sensor without checking other things first. Thoughts?

 

You can fiddle around with the connector & fuses, but it's usually heater element that goes bad inside the sensor.

 

Upstream are always more expensive than downstream. Downstream is usually the one that goes bad.

Exposed more to the elements. Good Luck

 

Thanks.

This seller has a "Denso" for $99 + shipping. Any reason to think that these could be knockoffs?

 

Pictures look legit, what they send you might not be. I never deal fleabay. Lots of "shady" sellers on there.

RockAuto has it for $127.00 I think. I deal with them all the time. Never had a problem. Fast shipping.

 

Robnik,

I was about to buy this on RA and saw this message at checkout:

Manufacturers recommend replacing O2 sensors in pairs (both Upstream or both Downstream). And older, slower sensor can cause an imbalance in the engine management system, leading to poor fuel economy and possible damage to the catalytic converter.


Guessing this doesn't apply here since there is only one upstream sensor?

 

^^^Sounds like a service writer at a dealership

sure, would be better to RR both
but
If there is no code tripping for the second O2 sensor, it’s working

 

I believe it's the intake air temp.sensor

 

Are there two upstream sensors on these 1st gen Tacomas? The bold text I pasted above seems to be saying I should replace BOTH upstream sensors or BOTH downstream sensors, but I thought there's only one of each?

 

Just replace the upstream. They're like light bulbs, you can't predict when they fail.

"If ain't broke, don't fix it!"

https://www.youtube.com/watch?v=pm7wqfKAEUs

 

One up, one down.

 

... have read or whatever somewhere sometime that these O2 sensors May Be 'Working' but with Age they might not be working Efficiently

i took a peeky at the upstream on under my rig and I have absolutely NO CLUE how that is ever going to be coming out for replacement after 27+ years original

 

When I “decided “ to RR my sensor
I started spraying PB…….every day……for a week prior to install!
Wasn’t too bad

 

Those nuts on mine look QUITE weathered

 

How am I supposed to remove this? Is there a nut/bolt to remove?

 

I've seen a method using a torch and careful air chisel to chip at it and still save the stud threads