So I have an unusual problem with my 2006. Since I got the car at 160k, it will throw a P0352 or P0353 once every few weeks- but has no performance problems. Did it 4-5 times in September and October. Stopped doing it for 6,000 miles. Started again early April. I initially replaced the coils with AM Denso units, no change. Load tested the IGF wiring and engine computer powers and grounds- ok. Tried a used engine ecu- no change. Finally caught the event on my digital scope. Let's begin with a known good example. Here we see the ICE crank sensor (BLUE) and cam sensor (RED) making smooth sine wave patterns on a 2009 at idle. Compare that to my 2006- also at idle. You can see a bunch of hash or EMF "noise" in the cam sensor signal. Here is the 2006 with more data- ICE motivating the car . Crank sensor (BLUE). cam sensor with hash/noise (GREEN). The engine has normal ignition operation; the IGT command for cylinder 2 (RED), and the IGF confirmation signal for all cylinders (Yellow-ish). Now here is the glitch event. the ICE is stopped but the car is moving in light throttle EV mode. You can see lots of noise and hash in both crank and cam circuits- apparently enough to cause the engine computer to falsely and erratically trigger the ignition and injectors. The IGT isn't regular which causes sporatic IGF- setting my codes. The only (assumed) possible source is the inverter- with the crank and cam sensors acting as antennas. My question is- has anyone seen/heard of this kind of failure? Any possible fault repair other than replacing the inverter? (could put capacitors across the sensor wiring to suppress the high frequency noise, but that''s a band-aid). thanks
Yes very common. Lower engine bearing damage causing subsonic vibration which distorts the cam/crank pgs the ecu gets confused and will throw roving misfires. Put the Car in inspection mode get under the front of the car and listen.
I don't have the 2006 wiring diagram in front of me at the moment ... I don't remember whether any of those circuits has a shield, and I don't remember where they're grounded. There's usually a network of white-with-black-stripe wires that are grounds, and a more exclusive network of brown wires to be quieter grounds for certain sensors. And the diagram shows the ground points they should be connected to, which might be things I would check.
Thank you but no - when the fault occurs the ICE is OFF and stationary (can't have engine bearings causing problems when they aren't moving)- also if I shift the car to neutral while the ICE is running, the inverter MG1/MG2 controls turn off (ie, the switching transistors in the inverter) and the electrical noise is gone while the ICE stays running
Also, if I do need to get another inverter , is there a preferred (improved) part number I should look for, or is any one for any Gen2 decent enough.
For future reference, here is the workup for DTCs P0351 P0352 P0353 P0354 - https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/2054m/cip0351.pdf
I will look closer at the ecu grounds but the data doesn't indicate that's the problem. Both cam and crank sensors share a common ground (NE-) back to the ecu which is connected inside to the main grounds (E1, E01, etc). My scope ground was connected to vehicle chassis. Any voltage drop on the sensor or ecu grounds should result in the sensor waveforms "floating" or being above the 0V point on the scope. My captures look to be pretty spot on- areas where the cam sensor isn't actively making a sine wave are very close to or at zero. I guess I have to look at the HV shielding grounds. Whatever it is shows up in everything I have scoped so far. It seems to affect the cam sensor more- I assume because it is physically located clser to the inverter than the crank sensor. Posted via the PriusChat mobile app.
