cobalt91

Isnt the egr tube working off the bank 2 cat? Would the leak affect both systems? If the flange for the cat is damaged bad enough to cause a leak, replacement of it is a must. Once this is done then test the sensors.

RA40

iTrader: (6)

Take a 10 count and let's see what the error code is before embarking on what the programming is behind the codes. I'm glad you guys have access to this material. In the end we're on the same team to help. The personal commentary in this exchange is unnecessary and leave that outside this discussion.

The solution will be a sealed exhaust and new O2 sensors for banks 1-2. Fingers crossed that the cat is within spec after this extended operating error period and that the EGR is not plugged as well.

LScowboyLS

obviously

This is incorrect.

quick primer:

Fail safe mode is the ECU's process of following a predefined set of rules for what to do in the case of particular fault detected in the system, which may or may not take the system out of closed loop.

In most cases, the resulting Fail-Safe Operation to be executed is in fact going to take the system out of closed loop, because the usual Fail-Safe Operation is typically some drastic "open loop" type of adjustment, such as Max. timing retardation, but not this time, in the case of the O2 heaters, the Fail Safe Operation that is invoked is to simply turn off the heater circuit to the particular O2 sensor which the abnormality was detected in, until the next KEY OFF cycle.

In the case of a post-cat O2 sensor, this will normally result in a code, but not a change in the how the vehicle runs, because you are not coming out of closed loop, nor are you entering the back-up function (Toyota's name for what we commonly call "limp home" mode,) which is the ECU going by a set of predefined levels (such as 5° BTDC ignition timing, calculated injection duration, etc.) which typically will light the MIL light but not store any codes. The ECU does not ever use post-cat information to make any changes in how the vehicle runs. Again, to reiterate, this is done on purpose, for emissions and other reasons I explained in post #23

this is a common misconception, perhaps yamae can clarify it even better than I have above, I am running out of ways to say the same thing


yes, the common egr tube leak would definitely cause problems in bank 2, although the OP said his leak was at the flange right where the cat connects, but if you are asking if a leak at the flange would affect the EGR system adversely, I am not sure that would actually cause an EGR problem or an EGR code necessarily. The EGR system is a lot more forgiving of what runs through it than is an O2 sensor or a cat.

I fully agree that this car is never going to run like it should until the exhaust leak is completely fixed, and any good muffler shop can do this, and likely without buying any expensive parts, those guys are magical with a torch! - I also will be very surprised if the bank 2 cat is not ruined at this point as a result of the leak going on for years and corresponding rich running roasting the cat.

DaveGS4

iTrader: (2)

Lscowboyls, please exit this thread. There is no need for personal commentary