Code P0135 O2 Sensor Heater Circuit Bank 1 Sensor 1

RYAN.TIM.J

MEMBER
2000 LEXUS GS 300
3.0L
6 CYL
2WD
AUTOMATIC
150,000 MILES

Hi, have this code from check engine light. Code clears, but then comes back on cold start. Warm start it does not. No impact evident, car drives fine.

Wondering what I am looking at to repair? I assume changing the oxygen sensor is the likely repair?

Thanks,
Tim

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5 Replies

JIS001

MECHANIC
3,411 POSTS

Majority of the time it is the A/F sensor heater element that is bad. Ohm out the 2 front upstream sensors. The 2 black wires and let us know the resistance on both sensors. Chances are the right side bank sensor is faulty. Here is a link on how to use a volt meter:

https://www.2carpros.com/articles/how-to-use-a-voltmeter

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Tuesday, December 17th, 2019 AT 12:03 AM

RYAN.TIM.J

MEMBER
57 POSTS

I checked both the front and back sensors. Black to black on the rear sensor is 15 ohm. On the front sensor is 0 or shorted or maybe open.

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Saturday, January 11th, 2020 AT 9:27 AM

JIS001

MECHANIC
3,411 POSTS

Open circuit.

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Saturday, January 11th, 2020 AT 9:42 AM

RYAN.TIM.J

MEMBER
57 POSTS

Should both the front and rear sensor be replaced at the same time? To make sure the fuel ratio stays in balance?

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Saturday, January 11th, 2020 AT 11:30 AM

JIS001

MECHANIC
3,411 POSTS

No, just replacing the one that is bad will be ok. Just make sure you get an A/F sensor and not an oxygen sensor. Big difference in price. The A/F is going to be expensive. If you are buying an aftermarket sensor I personally would recommend a Denso brand.