P0340

SteveSAS · 12-12-2019, 06:53 PM

The ECU seems to have an issue with bank 1 and may see it off timing for some reason and wont let you start to protect motor.
But when bank 1 signal is completely missing it uses bank 2 to work out timing for bank1 (only an approx.)and runs in limp mode. Which is why it cranks for longer.
You may have an issue with the variable valve timing on bank 1 or even jumped a tooth on the timing chain. Or ECU/wiring issues.
Could be few others things as well.
Your best to take car to an auto electrician

Knio · 12-12-2019, 08:32 PM

Thanks guys! I will double check all the wiring tomorrow when I get a scope, but so far everything still seems OK and the problem repeats even after resetting everything.

I discovered last night that the car was super low on oil.. it took almost 2 quarts before getting back up to normal

and was pretty dirty. I did an oil change, but the problem persists. The low oil makes me think it could be an actual VVT problem like a gallery not getting enough oil pressure or tensioner getting clogged or something like the other threads mentioned. I'm trying to think of ways to verify the VVT before committing to tearing it all apart.

Knio · 12-14-2019, 01:32 AM

I think I found something interesting.

I checked all the signals with a scope and they all look OK individually:

phase1.PNG

bank 1 at sensor
IMG_2156_1.JPG

bank 2 at sensor
IMG_2157_1.JPG

bank 1 at ECU
IMG_2159_1.JPG

bank 2 at ECU
IMG_2160_1.JPG

crank.PNG

crankshaft at ECU
IMG_2161_1.JPG

And then I noticed this drawing in the manual and decided to test both channels:

wave.PNG
IMG_2162_1.JPG
IMG_2163_1.JPG
IMG_2165_1.JPG
IMG_2166_1.JPG

It looks like bank2 is advanced about 2ms relative to bank1, if they're supposed to be lined up like the manual shows. this would be about 5 degrees.

I also tested phase vs crank, but these did not vary at all with RPM. maybe IVT doesn't kick in before 3500, or the ecu disables it entirely in limp mode.

I'm not really sure the 5 degree out of phase is an error or not without knowing exactly what the gears look like, but this timing could be off.

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12-12-2019, 06:53 PM	#1 (permalink)
SteveSAS Base Member Join Date: Jun 2018 Location: Australia Posts: 61 Drives: 370z Rep Power: 5364	The ECU seems to have an issue with bank 1 and may see it off timing for some reason and wont let you start to protect motor. But when bank 1 signal is completely missing it uses bank 2 to work out timing for bank1 (only an approx.)and runs in limp mode. Which is why it cranks for longer. You may have an issue with the variable valve timing on bank 1 or even jumped a tooth on the timing chain. Or ECU/wiring issues. Could be few others things as well. Your best to take car to an auto electrician

12-12-2019, 08:32 PM	#2 (permalink)
Knio Base Member Join Date: May 2011 Location: Palo Alto, CA Posts: 141 Drives: 40th Rep Power: 14	Thanks guys! I will double check all the wiring tomorrow when I get a scope, but so far everything still seems OK and the problem repeats even after resetting everything. I discovered last night that the car was super low on oil.. it took almost 2 quarts before getting back up to normal and was pretty dirty. I did an oil change, but the problem persists. The low oil makes me think it could be an actual VVT problem like a gallery not getting enough oil pressure or tensioner getting clogged or something like the other threads mentioned. I'm trying to think of ways to verify the VVT before committing to tearing it all apart.

12-14-2019, 01:32 AM	#3 (permalink)
Knio Base Member Join Date: May 2011 Location: Palo Alto, CA Posts: 141 Drives: 40th Rep Power: 14	I think I found something interesting. I checked all the signals with a scope and they all look OK individually: phase1.PNG bank 1 at sensor IMG_2156_1.JPG bank 2 at sensor IMG_2157_1.JPG bank 1 at ECU IMG_2159_1.JPG bank 2 at ECU IMG_2160_1.JPG crank.PNG crankshaft at ECU IMG_2161_1.JPG And then I noticed this drawing in the manual and decided to test both channels: wave.PNG IMG_2162_1.JPG IMG_2163_1.JPG IMG_2165_1.JPG IMG_2166_1.JPG It looks like bank2 is advanced about 2ms relative to bank1, if they're supposed to be lined up like the manual shows. this would be about 5 degrees. I also tested phase vs crank, but these did not vary at all with RPM. maybe IVT doesn't kick in before 3500, or the ecu disables it entirely in limp mode. I'm not really sure the 5 degree out of phase is an error or not without knowing exactly what the gears look like, but this timing could be off.