QuestionI have a caravan that keeps getting check engine light after starting. Codes 24,25,32. Changed tps and didnt help. After restartiing several times, it goes out for the day and runs great until next day, then same thing. All hoses and connectors are fine. On the a/c problem, not getting cool. replaced the compressor wth a rebuilt, the expansion valve and drier. Pressures are 28-30 low and 190-210 high. A/c cool but not cold. Output temp is 68-70 degrees. if you can offer any ideas, please let me know. I have evacuated and pumped down system for 1.5 hours yesterday and got a little better but still not cold. HELP with your expertise iif you can.
Answer25 iac, target idle not reached, vacuum leak
24 tps low, doesn't agree with map
32 EGR
OK, tonight I'm working out of a 97 driveability book but the two digit codes really haven't changed much over the years.
Basically the 24 code could mean the TPS circuits are having issues but more importantly I think it's the second description, TPS does not agree with MAP. In this scenario, at initial start up the computer knows what ballpark it's supposed to be in for idle. Using other sensors it fine tunes. This code is telling us that the computer knows where's it's supposed to be based on the position of the throttle plate and other sensors but for some reason the MAP sensor says that the pressure inside the manifold is NOT where it's supposed to be.
Next we've got 25. Idle air control motor circuits again like TPS is a possibility but more importantly it says it's not able to bring the engine RPM to a point it wants to by using the IAC motor. It could also point to a vacuum leak but most of the time we'd see a high idle, hear a hissing noise or something of that nature.
The last code I think is the kicker. EGR WILL cause a big driveability problem because it's allowing exhaust to enter the intake in situations where the computer is not intending and more importantly, CORRECTING for this extra air. EGR leaks are basically a vacuum leak that will sneak up on you. The particular code can be electrical or mechanical. Given your symptoms I would say it's mostly mechanical.
Check engine light and driveability side of things the crystal ball says put on an EGR valve with new solenoid and see how the thing drives.
A/C. A bit more tricky. Pressures are good enough to have another 10-15 degrees lower so I would be suspicious of things like a heater valve that's not fully closed or a blend door that is not fully shut. I've not had the pleasure of pulling too many "AS body" minivan dashes so I can't remember if they even use a vacuum operated heater valve. But... in the event that it does you'd be looking for a valve that has four heater hoses attatched to it and a vacuum line. Clamp off the two hoses leading to the dash and wait maybe as much as 10 minutes. The temp should drop even more since there's no more hot water running through the heater core and what's in there has been chilled by your working a/c system.
If you don't have a heater valve then a blend door would be doing all of your work for you. It's subject to binding up, cable fray, and if vacuum operated then the vacuum line could be pinched, corroded or disconnected all together. Now... I mentioned vacuum line and you've got engine problems... MIGHT be related but I doubt it so don't get too excited.
What you'll have to do is determine how the heat side of things is controlled. If you don't have a heater valve then you'll have to lay under the dash and try and trace down the blend door cable. You'll have need to make sure that you're getting full movement out of it, there's no binding and the cable's not frayed.
I really think it's not related to the a/c charge side of things. Oh... one thing I forgot, always take temp readings at the center vents, coldest setting and MAX air/recirculate mode setting. Shut the doors and roll up all the windows and measure after about 5 minutes. Make sure the door is unlocked :)
Doug
