Would anyone have an idea what could trip p0700,p1457,p1739 all at the same time - bad ground ??
Car is running fine.

I've removed the motor mount grounding strap and cleaned the connection points.

 

sounds like 2 different issues

evap system leak p1457 ....2 way valve, bypass solenopid valve, shut valve , hoses ..??

tranny issues..

 

P0700 sets anytime a 17xx series code sets. It is a generic trans code. Your code description is for the 3rd pressure switch. You should be able to search on here for it.

 

It may be two different issues. However, as I stated previously, it all started after an attempt to perform a timing belt change. Just wondering if lifting the engine slightly loosened a connection,etc.? Have looked, but found nothing. Will look again.
Just trying to do some analytical troubleshooting before trusting the DTC's.

 

Within the engine bay, the part that would cause P1457 is the purge valve. It's bolted to the intake manifold, #8 in the picture. Check the vacuum hoses to/from that valve. There SHOULD be enough slack for a fair amount of engine movement, such as you'd get while driving. Maybe a hose is just old & brittle & cracked?

 

This past weekend I checked all the lines around the purge valve and CVS. All appear to be ok.
I also tested the purge valve with 12v and a mighty vac. It operates
and holds and releases vacuum when powered up/down.
I then turned the ignition on and there is 12v at the purge valve plug.
However, I do not see ground continuity at any time.
Does the ECM send the ground sink signal at any particular time or is it random?
Thanks

 

I'm sure there's logic to it, but I don't know the scheme. A Helm repair book for your year probably has some information.

 

Not true. I had the p1739 set but no p0700.

 

I have just recently gone through a p1456 ordeal myself (similar to 1457) and have investigated most of these valves in great detail.

Pretty much all of the valves are operated by the ECM/PCM providing the ground connection, the 12V is applied by other means.

Also, I am very sure that the service manual stated that the purge valve is always open *after* the car reaches a certain temperature. So if you tested it below that temp then your readings or 12V (yes) and ground (no) are exactly as expected and do not indicate a problem.

Let the car warm up, then test. From my own experience I can tell you that once warm there should be a pulsing vacuum on the line from the purge valve to the canister. Just put your mightyvac on this line after unplugging it from the canister and take a measure. I believe it was about 20 inHg vacuum, but I could be wrong.

Anyway, as everyone else has already said, this is the only part of the evap system you could have touched doing the TB work you described. So go under the car, unplug the purge valve hose from the canister, test that this hose can hold vacuum with engine off, and that it produces vacuum with engine on and hot.

 

With no voltage applied to the canister vent valve it's normally open as it should be.
When I apply 12v to the cvs it holds vaccum as it should.
However, when I remove the 12v it still holds vaccum (solenoid doesn't drop out). I assume this isn't correct...?
Thanks