5th & 6th Generation (2002-2006 & 2007-2011)Toyota Camry Discussion for years: 2002-2006 & 2007-2011
Topics of discussion range from fuel economy, safety, modifications, performance all involving America's favorite family car, the Toyota Camry.
Our Camry has about 105,000 miles on it. Car is well maintained, I change the oil every 3 k or so and the air filter is clean (although it is not a factory air cleaner- it is a K&N filter). Other maint is done as specified by the warranty/maintenance book although the car is long out of factory warranty.
We occasionally pull a 800 lb pop-up tent trailer and just got back from the Sierras after driving up some pretty tall passes with it. Car ran great, got great mileage, temp gauge rock steady. I say this because it is probably the most stressful driving we do with this car. While we live in the city we are retired and the car is not exposed to constant heavy traffic, dust or snow. Mileage seems to have remained pretty steady, even with the hesitation.
Got home from the mountains and a couple days later the car began to hesitate when under load. The hesitation shows up as a slightly uneven surge when the car is going up a hill or when it is cold. About 20 mph the car seems to momentarily stop accelerating, then evens out and upwards of 40 mph I don't feel it at all. The hesitation is getting a bit worse over the last couple days in frequency, but still isn't felt on the freeway. I don't know if the hesitation is related to the recent trip to the Sierras.
I hooked up my OBD II computer to see if there are any DTCs, none shown, even left the computer on the car for a day to see if anything might pop up when the car surged, but the computer isn't seeing trouble codes.
My other thought was "got some bad gas", ran the tank out and put in new gas, fuel injector cleaner and dryer. With one new tank it hasn't helped. I haven't replaced the fuel filter yet.
Tried driving the car in 1st and 2nd gear only and found that the hesitation isn't dependent on what gear I'm in, but seems to be more about the speed and load. In neutral, slowly reving the engine, I don't detect anything that sounds or looks like a hesitation (just watching the tach).
Been reading about problems some Toyotas have had with unintended acceleration but I'm not sure that is my problem. I have to admit I didn't know that my Camry was "drive by wire" and maybe I don't understand it enough. Maybe a "reflash" might be needed?
My sense is that I should go ahead and do the next major maintenance items including plugs, but if I had a bad plug or plug coil wouldn't that show up as a Diagnostic Trouble Code item?
Could this be a bad injector or fuel filter? Wouldn't they produce a DTC?
Never saw any response to my letter but I have pursued it and if you are interested in the solution I'll put it here. The slight surge was called by the after cat oxygen sensor. Replacing the second oxygen sensor, at least that's what Toyota is telling me today, solved the problem. This is the third day that Toyota has told me that they solved the problem, with the first two efforts failures.
They have no idea why the failure of the second oxygen sensor wouldn't set up a diagnostic trouble code or been flagged by the computer.
The first efforts by Toyota included replacing the plugs and fuel induction cleaning. While I'm sure Toyota made money of overcharging for these service they did not stop the surging.
They told me that they jumpered the sensors on the exhaust stream one by one looking for a change in the surge and when they got to the second oxygen sensor it was fixed.
Whew.
I am having the same problem. I have been dealing with an OBD code of 0032 and 0420. I replaced the upstream and downstream O2 sensors and got rid of the 0420 code. This evening, i ran out to an errand with no problems, but when i headed home, the camry really hesitated during acceleration. Interestingly enough, the "check engine light" that was on, was off, but the code was still present. I think i am going to take the upstream 02 sensor back and have it replaced and go from there. Any other suggestions?
"I am having the same problem. I have been dealing with an OBD code of 0032 and 0420. I replaced the upstream and downstream O2 sensors and got rid of the 0420 code. This evening, i ran out to an errand with no problems, but when i headed home, the camry really hesitated during acceleration. Interestingly enough, the "check engine light" that was on, was off, but the code was still present. I think i am going to take the upstream 02 sensor back and have it replaced and go from there. Any other suggestions?"
Is your car hesitating or stumbling at low loads, low rpm? That's what mine was doing. It never "stalled", ran well at high speeds. on the freeway climbed hills without problems, got great mileage, and so on. Mine never had a OBD Code, that was the problem.
The Toyota mechanic told me that he found the problem by carefully "bypassing" each sensor going from the engine to the tail pipe. When he got to the O2 sensor I gather he "bridged" it into operating it correctly (actually he bridged the O2 sensor and it wasn't in the circuit at all as he explained it to me). I went to my Camry book and puzzled over this. I don't think that bridging the O2 sensor would always work (perhaps not at cold idle) but I guess it made the hesitation end so they just logically decided to replace it. It is too bad that the OBD II computer didn't show the failure, but maybe it failed in a way that was just "inside" the acceptable values the O2 sensor was supposed to read, but still causing this minor, but frustrating hesitation.
Oakland Toyota said that due to this experience they would inform Toyota Corporate of the problem and the solution to see if there are others having the same difficulty. If Oakland Toyota started some kind of thread for the corporation your Toyota Dealer might be able to find it.
Last edited by raleighmclemore; 03-15-2012 at 10:50 PM.
I discovered that Toyota put 2004 parts on the 2003 Camry. The guy at Autozone apparently worked for Toyota for a while and asked me to look at my manufacture date (inside the driver door). Mine was 08/2003, so we tried the 04 part. Code went away and it accelerated nice and smooth. I had never run into this problem before and i do all the work on my car.
Hope this helps.
The downstream/rear o2 sensor serves one purpose. To compare emissions readings with the pre cat o2/af sensor and decide if the catalyst efficiency is ok. If not it triggers a P0420 CEL. I have mine blocked off with a spark plug anti-fouler so I don't trigger the code. Its doing basically nothing now and all is fine. The downstream/rear o2 sensor had nothing to do with the hesitation problem. Upstream/front air/fuel/o2 sensor "could" do that. MAF sensor a vacuum leak from the air intake possible too.
Yeah I was aware of that. I replaced it anyway a couple weeks ago. Once I replaced the upstream o2 sensor, the hesitation issue was resolved, however, the check engine light came back on just now... Have to check the code. I fear I'm going to have to replace the cat converter.... $2000+ in CA. back to the drawing board.
As stated above, all you need is the spark plug anti-fouler mod for $7. Package comes with 2. For the I4 Camry only 1 should be used.
The mod resolves bad (IMO) factory ECU programming. Bad because Toyota assumes that a catalytic converter that falls below 90% efficiency will fail a state smog test so a P0420 is triggered. Wrong! By changing the location of the downstream o2 sensor in relation to exhaust flow emissions, restricting the flow of emissions around the sensor, and keeping the sensor cooler, the P0420 vanishes. At some point you will fail a smog test, or have issues with a clogged cat, but that will be several years, maybe the life of the car before that happens.
The spark plug anti-fouler needs a mod - drill the end off - to fit the tip of the o2 sensor when screwed in. Many say use 1/2" drill bit. But I found on the Camry its important to use only 1 anti-fouler because the extra length will be hitting the oil pan, no good. So you want the tightest fit possible at the sensor tip. I used 3/8" and rounded it out till the sensor just barely fit through. There are many pictures of the anti-fouler in action, do a search to see some.
Why does a cat lose its efficiency and trigger a P0420? Usually oil consumption or anything heavy in oils or lubricants put in the gas or brake lines like seafoam, mmo, etc. Oils and lubricants have high flashpoint, dont entirely burn off, adding "load" to the catalyst media. Once the load gets too high or the catalyst media inside the cat "gets wet", efficiency drops off because the cat cant get hot enough to burn off exhaust contaminants.
A P0032 CEL should be the upstream af/02 sensor. Its physically broke (according to the ECU). Use a denso for replacement, they are cheap and toyota's ECU recognizes them. Do not use universals or alternate types. They may calibrate incorrectly. .
Yeah this is a stock vehicle. I came home, plugged in the computer and nothing came up and the check engine light is off... wondering if i have a short somewhere.
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