Could a motor mount result in a CEL?

[SpeedySolara]

Allow me to explain...

When I put my car in reverse I get a big jolt due to a bad rear motor mount. As a result, the top portion of the OEM y-pipe has suffered a small crack and is causing a minor exhaust leak which I believe is giving me a P0420 CEL code. Am I making an accurate assumption? I'd like to also mention I just changed my catalytic converter with a brand new aftermarket cat (for the second time this year) & my O2 sensor was replaced at the beginning of 2011 with an OEM O2 sensor. With that being said, I highly doubt the cat or sensor are throwing this code. What do you guys think it could be?

[PaulR]

Allow me to explain...

When I put my car in reverse I get a big jolt due to a bad rear motor mount. As a result, the top portion of the OEM y-pipe has suffered a small crack and is causing a minor exhaust leak which I believe is giving me a P0420 CEL code. Am I making an accurate assumption? I'd like to also mention I just changed my catalytic converter with a brand new aftermarket cat (for the second time this year) & my O2 sensor was replaced at the beginning of 2011 with an OEM O2 sensor. With that being said, I highly doubt the cat or sensor are throwing this code. What do you guys think it could be?

Hi SpeedySolara,

The P0420 code could definitely be the OEM y-pipe. The ECM isn't (usually) able to tell whether the issue is with the sensor or hardware, and since you have replaced the most common faulty hardware components for this car, I am willing to bet that may be your problem.

[SpeedySolara]

Thank you for your response Paul. I actually got the y-pipe welded/repaired and it fixed the jolting BUT it only lasted two days before it cracked again. I wasn't able to tell if the crack was causing the CEL because it came back on so quickly. Do you think rear motor mount continues to cause the stress crack? If not, what else could it be? Finally, from where do you adjust the transmission kick down and how do you know if it's adjusted correctly?

[chriscarter]

You people really don't bother reading previous threads and posts, do you?

[PaulR]

Thank you for your response Paul. I actually got the y-pipe welded/repaired and it fixed the jolting BUT it only lasted two days before it cracked again. I wasn't able to tell if the crack was causing the CEL because it came back on so quickly. Do you think rear motor mount continues to cause the stress crack? If not, what else could it be? Finally, from where do you adjust the transmission kick down and how do you know if it's adjusted correctly?

The second picture on this link is the kickdown cable: http://www.toyotanation.com/forum/showt ... hp?t=53223

On my Solara, there was a little stopper. That stopper, when set to factory specs, is as close the rubber grommet as possible. I made it as tight as possible just to see what happened during a test drive. It shifted extremely hard, like a race car, as some might say.

If you don't mind my asking, how did they weld it back together? Since that piece undergoes normal heat and vibration, it takes quite a bit of stress on any welds. Where is the weld on the pipe?

[SpeedySolara]

If you don't mind my asking, how did they weld it back together? Since that piece undergoes normal heat and vibration, it takes quite a bit of stress on any welds. Where is the weld on the pipe?

The stress crack is on the top of the first bend on the y-pipe. They put the tig welder on top of the pipe and welded it.

[PaulR]

If you don't mind my asking, how did they weld it back together? Since that piece undergoes normal heat and vibration, it takes quite a bit of stress on any welds. Where is the weld on the pipe?

The stress crack is on the top of the first bend on the y-pipe. They put the tig welder on top of the pipe and welded it.

Did they use anything to patch it or just the electrode to fill it in? Does your engine shake (more than normal) when the engine is on? I definitely think the Y pipe could be under more stress because of the bad rear mount, but I've also seen bad welds crack out almost instantly.

[SpeedySolara]

Did they use anything to patch it or just the electrode to fill it in? Does your engine shake (more than normal) when the engine is on? I definitely think the Y pipe could be under more stress because of the bad rear mount, but I've also seen bad welds crack out almost instantly.

I think they just used the electrode and no shaking just jolts in reverse and sometimes when changing gears.

[Brandoe91]

why don't you try and get a used y pipe from the junkyard. Also the jolted you feel could also be from a bad front mount.I had the same jolt when I shift to R . I thought it was the rear mount but when I took the engine out of my es300 the other day, the rear mount was good while the bushing in the front was gone.