I have a check engine code P1604 QDM1, i have seen a few posts saying its either the evap canister, boost solenoid, or tcc, Which should i replace, the tranny is brand new but i did change the fluid last week, could i have messed something up, fluids are good, and the tranny is brand new about 40,ooo km ago. The evap canister that little can near the washer fluid tank, that may be wrong? Ill change the boost solenoid and see what happens.

i'll go with the boostcontrol solednoid its so easy to change

Is there anything wrong with your boost? If not, why are you changing it? Does your TCC lockup smoothly at 48 mph?

I'm not a big fan of shotgunning parts to fix a problem. The Evap could easily be the problem, and is much more likely if you have no boost problems.

I also have this 1640 code and am trying to track it down. It looks like you have a 95? I have a spare canister and extra purge valve that I picked up at a junkyard.

I just had a thought, Bill...and vets, do you suppose an evap canister purge valve could give a bad reading to the ECM/PCM if vacuum lines were rotted or broken? Thinking back mine started probably around the time the mod bug had a grip on me. CAI

Well I have a cai and just put on a smaller supercharger pulley about two months ago and the cai has been on there for about 1.5 years. Its the first time the check engine light has been on in my car. What should I do, its a new tranny maybe only 40,000 km max, change the evap canister, and boost solenoid and go from there? any suggestions anyone?

I'm looking into the manual. If yours is like mine, then everything is working fine and you get a check engine light.

I think it'* the evap, but going to post more once I consult the manual in front of me.

like willren said, dont change your boost control if you have no boost problem, useless

i change mine but i was having terrible loss of boost, my car was only running 16.4 ...
now 15.2

dont waste money on a boost control solenoid,... if you have normal boost

Ok, if your boost is working fine and your TCC is working fine, then you'd want to look at the evap purge. Aka charcoal canister. On top there is a solenoid. Once the motor is on and running and air temp is at least 50 degrees it will begin working in 25 seconds if the motor is warmed up and 2.5 minutes if it is cold.

Mine was warmed up already and 25 seconds after start up I touched the soleniod with my finger and I could feel it clicking/working. My problem in intermittent and I believe the valve stops working or I have another issue. If your evap is working and the code is still on, post it here and we'll diagnose it further.