Heys guys. I recently picked up an 01 is300. Bought from a coworker because it had “issues” and he was tired of messing with it. After cold soak the car will idle/run/shift great for about 1 minute max. Throws fault p1121 for APPS. I put a new APPS on it first which didn’t change anything. After that found a good used complete TB and put it on with same results. Replaced all plugs and put new connectors on coils. New MAF sensor. After MAF car idled better but still had same issues with very bad hesitation with any throttle input. Replaced APPS and TCM connector after they broke when removing. Removed all loom on passenger side of engine and harness looks fine. Back probed vpa and vpa2 at ecu and voltages are in spec with apps at rest and fully turned. I’m at the point to where all it can be in my head is the ECU. Just wanted to run this by the guys that’s been around this platform for a while before I forked the money over for a new ECU.
Any news so far..?
Do you have a Scan Tool capable of reading Live Data?
Seems like it's been a while, just wanted to chime my own 3 cents in for the future.
It is weird that the car will Run for a Minute and then Stall, even weirder that MAF Sensor made things better, it could be an unrelated issue that trips this specific Code. If you have a Scan Tool, first of all check the Freeze Frame Data, which will tell you what ECU saw at the moment, which would be a way to confirm a problem, then, depending on what you see, check the Engine Live Data, or keep the Backprobes with something like an Oscilloscope and go for a ride, see if the Values will get out of normal range.
Other than that, you can simply disconnect the APPS and see what happens, yes, you will only have a pretty narrow Mechanical Backup, but if the car won't stall without the Sensor, and you will get P1120 code instead, it can tell a lot as well.
