I have 1999 Toyota Corolla with about 150,000 miles. The check engine light had come a couple of months ago and the dealer said the charcoal canister needed to be replaced ($400). Within a couple of weeks after we had the charcoal cannister replaced, the charcoal cannister replaced, the check engine light came on again. Now the dealer says it is the bank 2 oxygen sensor (another $400). We had the catalytic converter replaced within the last three years and I have had the charcoal cannister replaced before. The car does burn a little oil. I read one of the cartalk discussions that there could be several factors causing the error code. My questions are:
1. What bad will happen if I don’t replace the oxygen sensor?
2. Is is possible that the error code is more general than the dealer says, and they are just replacing parts in order.
3. How difficult is it to replace the oxygen sensor myself?
A bad O2 sensor will likely result in increased fuel use and reduced gas mileage. Not good.
Do you know the actual code? If so, post it here. It will help.
$400 seems high for an O2 sensor. If you have the correct tool for sensor removal and installation (and you can get at the sensor) you should be able to replace this yourself. Parts stores sell the tool and the sensor.
After 10 years the old sensor may be difficult to remove, so be prepared for that.
Another option is to take the car to an independent mechanic. They are usually less expensive than the Toyota dealer.
Replacing two canisters in 10 years is highly unusual. “Topping off” your gas tank on some cars can cause fuel to get through the vent line and into the charcoal canister, saturating the charcoal bed and causing failure of the canister. Do you do this?
The oxygen sensor likely failed because of prolonged mild oil burning. The residue of this can coat the surface of the sensor making it inoperative. It needs to “feel” the passing exhaust to measure the amount of oxygen. Nothing in this recommendation sounds out of place to me.
The costs are high, however. There’s no reason to be taking this vehicle to a dealer. You can cut your costs by finding a reputable independant shop.
I went back and looked at my invoices. The dealer replaces the charcoal cannister in January 2007 when code PO446 registered. That code came up again in May 2008 and they replaced the cannister again without charge. In May 2009 code PO136 came up. We did not get the work done at that time. When we took it back in to get it fixed for inspection, code PO446 came up and we paid to replace the charcoal cannister. After that, the light came on again and now they say that it is PO136.
- Poor fuel milage and carbon buildup.
2.Absolutely, IMO o2 sensor codes are most of the time NOT the o2 sensor, but something further up the line throwing the o2 code:) like lean or rich fuel. Get someone with a better machine to run diag.
3.Not very, depending on it’s location, autozone sells a speacial socket that will fit on them but has a slot for the wires to go through.
***2.Absolutely, IMO o2 sensor codes are most of the time NOT the o2 sensor, but something further up the line throwing the o2 code:) like lean or rich fuel. Get someone with a better machine to run diag. ***
This error seems to be too much Oxygen at the downstream O2 sensor. The only thing upstream that is likely to cause a P0136 would be a hole in the catalytic converter or exhaust pipe that is letting air in. Anything further upstream – e.g. a lean fuel mixture, would presumably cause an error at the upstream O2 sensor as well or instead.
Not very, depending on its location, autozone sells a special socket that will fit on them but has a slot for the wires to go through.
They do, but it’s not needed if the O2 sensor is not going to be reused. One can just cut the wires and use a regular socket.
The big thing is that an O2 sensor that has been in the car for a decade is likely to be REALLY hard to remove. Since it is the downstream sensor, replacing it almost certainly means working under the car which means jackstands or (better) ramps. And probably access will be poor because they will have mounted the sensor such that a rock or block of ice can’t easily strip it off the car. In my limited experience getting them loose involves breaker bars with two or three foot pipe slipped over them to increase leverage … and maybe repeated applications of heat from a propane torch and PB-Blaster as well. It might be necessary to remove the section of the exhaust system with the O2 sensor in it just to get access to the sensor. And that will mean dealing with nuts and bolts that are probably hopelessly rusted and have to be ground off or otherwise brute forced. Not recommended to any but the most determined shade tree mechanic I think.