Hi Folks,
I could use your insight and help.
2000 Camry CE, 5 Speed Manual trans with 186,000 on the clock. This car runs great and I want to keep it.
Just got the P04020 code, Catalyst system efficiency below threshold Bank 1.
Spent a few hours online researching this and seems like my initial options are:
A gallon of lacquer thinner in a quarter tank of gas (or any commercial product)
Replace the downstream O2 sensor
Take off the catalytic converter and wash in soapy water
Am I on the right track?
Please let me know your thoughts on how to deal with this.
Thank you for your time.
Cheers
its possible its just a o2 sensor especially if its never been changed. it also could be a wire to the o2 sensors that is broken or chaffed. I have had a connector to a o2 sensor that was dirty because a power steering pressure sensor was leaking and power steering fluid leaked into the connector. if your code reader has the option to see if the o2 sensors are cycling properly, check that first. you would also see if power is getting to each of them.
Every engine today has a pre-cat. The correct term is warm-up cat. The issue that Pat Goss referred too was common with the Nissan 2.5l engine because the cat was really close to the exhaust valves and that engine uses a lot of valve overlap in place of an egr valve. I have not heard of this issue with Toyotas.