Check engine, trac off and vsc light on at same time, have error codes! read on...
05-22-17, 11:45 PM
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Check engine, trac off and vsc light on at same time, have error codes! read on...
I seriously need your help. A P0420 error code popped up yesterday and my emissions inspection is next month AGGH! I love my 2002 Lexus ES300 (128K miles) and I just don't want to let it go if I have to pay a crapload of money to replace fix the cat on Bank 1.
I want to mod an O2 sensor before bringing it into a dealer. BUT I have no clue which 02 sensor to mod.
Q: In your professional opinion, which O2 sensor do you think I should mod (please see attached photo)?
Ps Thank you for your professional advice in advance!
DIYDD
I want to mod an O2 sensor before bringing it into a dealer. BUT I have no clue which 02 sensor to mod.
Q: In your professional opinion, which O2 sensor do you think I should mod (please see attached photo)?
Ps Thank you for your professional advice in advance!
DIYDD
05-23-17, 05:20 AM
#2
The upstream O2 sensor that needs to be replaced is the front one (radiator side). It is recommended to buy an OE "plug and play" replacement such as Denso to avoid problems. To help ease removing the old one, spray the threads ahead of time with PB Blaster or equivalent.
05-23-17, 08:03 AM
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this one?
The upstream O2 sensor that needs to be replaced is the front one (radiator side). It is recommended to buy an OE "plug and play" replacement such as Denso to avoid problems. To help ease removing the old one, spray the threads ahead of time with PB Blaster or equivalent.
Ps HomerJay, I am trying to do what this
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Thank you so much!
Frustrated ;/
DIYDD
05-23-17, 09:21 AM
#4
Sorry, I am not able to view your pictures or video. You need an upstream (which means before the cat.) bank one O2 sensor. BTW I am not a professional mechanic, but happy to help.
05-23-17, 09:56 AM
#5
Actually that's incorrect - you need to deal with the downstream sensor. P0420 is something like "catalyst below efficiency threshold." The upstream O2 sensors are used by the ECU for closed-loop fuel operation. The ECU compares the downstream sensor to the readings from the upstream sensors to determine if the catalyst system (any of the three cats) are not performing to spec.
"Modding an O2 sensor" - an O2 sensor spacer on the downstream sensor - and obviously I'm not condoning this (and note that it will fail visual if your state does that), such as
...will pull that sensor out of the exhaust stream and fool the ECU into thinking everything is fine. Then your car will pass smog as long as the cats aren't degraded to the point that it fails the sniff test.
"Modding an O2 sensor" - an O2 sensor spacer on the downstream sensor - and obviously I'm not condoning this (and note that it will fail visual if your state does that), such as
...will pull that sensor out of the exhaust stream and fool the ECU into thinking everything is fine. Then your car will pass smog as long as the cats aren't degraded to the point that it fails the sniff test.
05-25-17, 03:00 AM
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Downstream?
Actually that's incorrect - you need to deal with the downstream sensor. P0420 is something like "catalyst below efficiency threshold." The upstream O2 sensors are used by the ECU for closed-loop fuel operation. The ECU compares the downstream sensor to the readings from the upstream sensors to determine if the catalyst system (any of the three cats) are not performing to spec.
"Modding an O2 sensor" - an O2 sensor spacer on the downstream sensor - and obviously I'm not condoning this (and note that it will fail visual if your state does that), such as https://www.amazon.com/Blox-Racing-B...ct_top?ie=UTF8
...will pull that sensor out of the exhaust stream and fool the ECU into thinking everything is fine. Then your car will pass smog as long as the cats aren't degraded to the point that it fails the sniff test.
"Modding an O2 sensor" - an O2 sensor spacer on the downstream sensor - and obviously I'm not condoning this (and note that it will fail visual if your state does that), such as https://www.amazon.com/Blox-Racing-B...ct_top?ie=UTF8
...will pull that sensor out of the exhaust stream and fool the ECU into thinking everything is fine. Then your car will pass smog as long as the cats aren't degraded to the point that it fails the sniff test.
Ps Several mechanics quoted a minimum of a $1000 and the car is running perfectly.
Thanks for your professional help.
DIYDD
05-25-17, 07:38 AM
#7
You need to address both downstream sensors (Sensor 2 on each bank). I'm unfamiliar with the post-2001 1MZ-FE motors, since my newest one is an '01 and only has one downstream sensor, not two.
(Also I'm not a professional)
(Also I'm not a professional)
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05-25-17, 09:11 AM
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sensor?
DIYDD
05-25-17, 07:17 PM
#9
Yeah, both downstream. P0420 won't be specific as to which bank is not catalyzing efficiently AFAIK (but keep in mind I only have 1MZ's with a single downstream sensor).
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Beingreen89 (02-19-24)
10-02-19, 10:11 PM
#12
Intermediate
If you have a code on one bank/sensor.... Swap sensors to see if the problem follows the suspected bad one. If the code doesn’t follow the suspected sensor, that CAT is bad. If it follows the suspected sensor, the sensor is bad.
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