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max a/c and max heat caused check engine light

4K views 14 replies 9 participants last post by  sheila 
#1 ·
So I drive for two hours with the heat on max. I stop the car and turn it off. turn it back on with the heat on max. I hit the Max A/C button, the engine bay starts to sound strange (although it's a quiet difference in sound I just have an ear for these things) and after about 20 seconds the check engine light turns on. I don't have access to a code reader until Monday. An idea what could be wrong?
 
#4 ·
Which would trigger the voltage light, not the CEL.

OP, there's not much point to speculating on your issue at this point. The most you can do is see if the clutch is locking and unlocking properly. Once you get the codes we can go further.
 
#5 · (Edited)
The A/C clutch spins occasionally although I'm not sure if it spins when it is supposed to or not.

I got the codes today... there is one I was only able to see from the KOEO. P1464 Air Conditioning Demand Out Of Self Test Range

Also there were the codes P0171 (lean bank 1) and P0174 (lean bank 2). I think it might just be the fuel filter needs to be replaced or something.
 
#6 ·
171/174 are due to vacuum leaks 99% of the time.
 
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#7 ·
The car stalled when I went into Neutral on steep hill. The gas tank was at 1/2 before the stall. I started it right after and it was at 1/4 tank. It took about 15-30 minutes of driving on flat ground for the tank to get back to 1/2. That's the only time it's stalled.

I read online that if turning the a/c on causes a lean condition it could be a problem with the electric fuel pump.
 
#8 ·
This morning after driving for 10 seconds all interior illumination flickered, the fuel light came on and the car stuttered a little. I was going 10 kph at the time. This all happened simultaneously for only a split second. I have a 1/4 tank and the hvac was off.
 
#9 ·
The stalling has become more frequent. The electronics freak out and then it dies. Seems like it could be a fuse or a ground but if there's a vacuum leak bad enough I suppose it could just die...

some sort of hose that says "abs vapor vent" on it melted because it was too close to the exhaust. I touched it to look at it and it broke like a twig. Have not driven the car since I broke that though.


The strange things is sometimes it runs like a champ and sometimes(usually shortly after starting ) the dash freaks out and it dies.
 
#10 ·
How's your battery? Mine started illuminating all dash lights for a brief time and it has been posted a weak battery triggers some self tests. Others have posted a weak battery causes all kinds of odd things. Mine started just fine but after testing the battery it was getting weak, replacement took care of my all dash lights illuminating and the returning to normal. You have a code, Air Conditioning Demand Out Of Self Test Range. The fuel level and self tests sound electrical to me. Don't doubt the lean is probably vacuum leak. Easy to have the battery tested.


Scott
 
#11 · (Edited)
How's your battery? Mine started illuminating all dash lights for a brief time and it has been posted a weak battery triggers some self tests. Others have posted a weak battery causes all kinds of odd things. Mine started just fine but after testing the battery it was getting weak, replacement took care of my all dash lights illuminating and the returning to normal. You have a code, Air Conditioning Demand Out Of Self Test Range. The fuel level and self tests sound electrical to me. Don't doubt the lean is probably vacuum leak. Easy to have the battery tested.


Scott
My battery died in a Walmart parking lot the other day. Luckily I was at Walmart so I just went inside and bought one. I wish I had known the battery was the issue before though. I could have paid Ford to replace the Motorcraft Maxx for a pro-rated charge. That fixed the flickering lights issue.

I think the lean codes were caused by the vapor vent hose having been melted by the exhaust. I knew I hit the vapor vent hose when I was trying to pull off the heater core hoses but I didn't realize it was so close to the exhaust. So I replaced it and no check engine lights so far.

The only issue I'm still having is somebody did a poor job of installing the viper remote starter (from previous owner) and when I use it the passenger headlight goes out for 5 minutes to one hour. Although when the battery was having issues the passenger headlight would go out too.

Oh and the Air Conditioning Out Of Self Test Range code could have been because I had the heat on when I did the KOEO test.

Last thing I can think of is if I turn the steering wheel when I'm stopped or if I'm driving slowly and I turn the steering wheel all the way to one side... the rpms shoot up and down by about 300 rpm. If I shake the steering wheel at that setting the rpms go up and down.
 
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