Check engine light on (evap system leak)

Redjeepht

Redjeepht

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I stopped at Orlieys to have them look up the reason for the check engine light that came on two days ago. It said (check gas cap) or Evap system leak (small)... I am pretty positive I know what it is. And I am feeling really stupid, because it's my fault...

I didn't notice the disconnected vacuum line (going into the firewall), and I tried to charge the AC. I tried to use the O'riley rental kit & the basic cans (even after a lot of research/YouTube I still manage to struggle with the "filling part" -( is it getting refrigerant in, sort of guessing...) Anyway, I just gave up and returned the tool. Then, a few weeks later, I found a section of the vacuum line missing, I put in some tubing & clamps, and The air starts blowing about the vents much better (still not cold, just improved blowing). I pull a vacuum & it's NOT holding a vacuum. This is where I should have stopped and figured out what to do. But I put in some refrigerant and then took it out because the pressure was still high.

So I just returned the tools and figured it would have to wait. I guess that was a mistake, leaving the pressure high ( I made sure to not have the air on at all, so I was hoping that would keep it okay until I got it fixed.

The other day I noticed a hissing noise from the hood after a drive. I open it up and the radiator has a tiny crack on the top, coolant sizzling. SO I'm guessing this is the cause of the check engine light.

Hopefully I can get some helpful adcice, 1. how do I relieve pressure from the system? 2. Is there anything besided the radiator the may be damaged to the overpressure? do I fix pressure/jb weld small crack/refill radiator. OR Do i fix thehigh pressure and then replace w/ new radiator?
 
IF the radiator has a crack with coolant sizzling out; that is the first thing to take care of.
You will need to replace the radiator before you overheat the engine.
IF the A/C system pressure is too high; the High Pressure CutOut (system safety) should stop the compressor from causing damage to the system.
I am of the opinion that unless you know what you are doing (prior experience); owners should not be adding refrigerant to their A/C system.
Take the Jeep in to a qualified technician to resolve your A/C problems.
 
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Evap code might be as simple as a new gas cap.

My 97 needed a new charcoal cannister and solenoid.

Grab a Denso radiator off Rock Auto. Check your fan clutch.

-Mac
 
These auto parts stores reading codes for people is really a disservice. Great for selling parts, not so great for actually fixing cars.
 
You have multiple unrelated issues.

If the rad is cracked, the first thing you need is a radiator and coolant. This has nothing to do with the evap code or AC system.

For the evap leak, you probably only need a gas cap. This is most likely the cause of the code.

The vacuum line through the firewall is used to control the location the air comes out.

If your AC system won't hold a vacuum, you have a leak, so you're pressure won't be high long. AC work is something I wouldn't suggest learning by yourself.
 
JKP said:
You have multiple unrelated issues.

If the rad is cracked, the first thing you need is a radiator and coolant. This has nothing to do with the evap code or AC system.

For the evap leak, you probably only need a gas cap. This is most likely the cause of the code.

The vacuum line through the firewall is used to control the location the air comes out.

If your AC system won't hold a vacuum, you have a leak, so you're pressure won't be high long. AC work is something I wouldn't suggest learning by yourself.
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Thanks for the replies, everyone. I'll order the radiator & gas cap and then take it in for the AC leak. Hoping that its not crazy expensive since it at least blows, but I might as well pay up because it's really hot in FL. And working AC in the Jeep would make it "perfect" and I enjoy it already.
 
Wow. Good luck. I had all those problems, just not all at once. Of course, the radiator came first (took it to mechanic). Then, I must have run it for two more years, until state emissions said that the check engine light must be fixed. Two mechanics and $1000 dollars later, that was fixed. The air conditioning was last and that has been blowing ice cold for another two years. You probably should have just taken it to a certified mechanic unless this is a fun learner for you.
 
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ChasUGC said:
Wow. Good luck. I had all those problems, just not all at once. Of course, the radiator came first (took it to mechanic). Then, I must have run it for two more years, until state emissions said that the check engine light must be fixed. Two mechanics and $1000 dollars later, that was fixed. The air conditioning was last and that has been blowing ice cold for another two years. You probably should have just taken it to a certified mechanic unless this is a fun learner for you.
Click to expand...

Yeah, it is kind of a fun learner for me. I definitely enjoy trying to save money by doing as much as I can myself. I just filled it up with Redline MT-90, (my first time ever replacing transmission fluid, filled through the shifter). Unfortunately, it's not any better and still grinding.

I think I won't have much trouble replacing the radiator, I've done a motorcycle radiator and a car a/c condenser before.

I am still contemplating the A/C repair for myself vs a mechanic. I know how to pull a vacuum and the parts on Amazon are pretty cheap for a complete kit. I feel like the compressor is faulty because it was not turning on, which is what needs to happen for the refrigerant can to be drawn into the system. As far as I can see, everything is pretty accessible, and ( I don't think it would be too hard to unbolt the old components/ throw new o-rings & new components & fill it slowly)

Also, I got the new gas cap and the check engine light did not go away.
 
For the rad, just loosen the bottom bolt on ea side, don't take them out, as the holes in the rad mount are slotted. Much easier to drop the new one in and set it on the two bolts.

AC is not hard, but you need to thoroughly read up on it in the FSM if you have never done it before. FSMs are available under Resources.

However, the AC compressor is not turning on because the system is empty and the low pressure switch is shutting it off to prevent compressor damage. You can partially fill the system when it's under a vacuum just by attaching a can and it will flow into the vacuum. However, once it stops flowing, you will need to start the Jeep and turn the AC on. You will most likely have to jumper the low pressure switch initially to get the compressor to turn on and suck in refrigerant.

Did you clear the evap code and it came back?

If you are going to work on your Jeep, I'd suggest getting a bluetooth OBDII code reader that works with your cell phone to read codes, reset codes, monitor various engine parameters, etc. They are not that expensive.

Also, please fill in your profile info on your Jeep, it makes it much easier for folks to help you out.

If I was in you area, I'd be glad to help out, but Tampa is a bit far, haha. But there are lots of folks willing to share their knowledge on here.
 
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JKP said:
For the rad, just loosen the bottom bolt on ea side, don't take them out, as the holes in the rad mount are slotted. Much easier to drop the new one in and set it on the two bolts.

AC is not hard, but you need to thoroughly read up on it in the FSM if you have never done it before. FSMs are available under Resources.

However, the AC compressor is not turning on because the system is empty and the low pressure switch is shutting it off to prevent compressor damage. You can partially fill the system when it's under a vacuum just by attaching a can and it will flow into the vacuum. However, once it stops flowing, you will need to start the Jeep and turn the AC on. You will most likely have to jumper the low pressure switch initially to get the compressor to turn on and suck in refrigerant.

Did you clear the evap code and it came back?

If you are going to work on your Jeep, I'd suggest getting a bluetooth OBDII code reader that works with your cell phone to read codes, reset codes, monitor various engine parameters, etc. They are not that expensive.

Also, please fill in your profile info on your Jeep, it makes it much easier for folks to help you out.

If I was in you area, I'd be glad to help out, but Tampa is a bit far, haha. But there are lots of folks willing to share their knowledge on here.
Click to expand...

I'll fill in the profile info. Also, the Evap code (reason for the CEL) did actually seem to go away with the new gas cap. Thanks for the advice on the radiator replacement.
 
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OKay. New radiator installed. Super easy! (I wrench pretty slow, so it just took me a little while). Besides the new radiator brackets not accepting the previous screws. I ran down to the hardware store and got some bolts/nuts because I couldn't even tell if the new one was threaded. new radiator came with 4 fittings that were not on the removed radiator. Are those for auto models? I left them in the bag.

Test drive, everything running good, checked the coolant overflow reservoir, still at full line.

(the belt is super squeaky, looks a little old too, so that will be soon.)

Also, @JKP, In a previous post you wrote the the A/C system is empty. When hooked up to the A/C gauge tool, it reads high pressure on the low-pressure side. Also, forgot to mention that the Little actuator thing on the passenger side under the dash is damaged. I'm going to look in the service manual.
 
I said when you pull a vacuum on the system and it's empty, the compressor won't run because of the low pressure cut off switch.

If you have charged the system, and the gauge is reading high, is the compressor running when you are taking this measurement?
 
JKP said:
I said when you pull a vacuum on the system and it's empty, the compressor won't run because of the low pressure cut off switch.

If you have charged the system, and the gauge is reading high, is the compressor running when you are taking this measurement?
Click to expand...

No, I don't think it was running when i was doing the measurement. It would spin the pulley if it was running right? It did not spin.
 
You were measuring what is known as the static pressure when the compressor is not running. The low and high sides will equalize when it's not running. There is no set pressure for this, but it tends to be 80 - 100 PSI. You can't measure the low or high pressure unless the compressor is running.
 
You might be aware but sending just in case. If you turn the key to the on position and off 3 times and on the third leave in the on position….dont start it. The codes will read out on the odometer display.
 
2001slvrstntj said:
You might be aware but sending just in case. If you turn the key to the on position and off 3 times and on the third leave in the on position….dont start it. The codes will read out on the odometer display.
Click to expand...

I did not know that. Thanks.

Also, I just ran into a problem. I guess something with the installation yesterday is not doing so well. It's leaking and the CEL is on. Maybe it's a hose. Or it could very likely be the two PLASTIC Screw in things on the bottom facing the engine, I reused those from the old radiator. Because the new radiator had 4 brass fittings that could be screwed in, but they looked like they were supposed to plug into something.
 
Gotcha. The code was P0455 again. The Evap leak. I did fill up gas this morning... I made sure the cap was on okay, removed the negative from battery and reattached 10 mins later. CEL did not come on.

As for the radiator, it wasn't too low, so i just put a clamp on the reservoir hose because it was missing one (and loose enough for liquid to leak from) So that should be good, I'll keep a close eye on it though.
 
Might be time to check the evap cannister and solenoid. For 2003 I think they're tucked up next to the fuel filler neck.

My 97 was easy...bolted to the fender.

After the Jeep warms up you should be able to feel the solenoid clicking.

-Mac
 
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