A quick search on engine-codes.com returned this:

P0599 BMW - Thermostat Heater Control Circuit High

Possible causes
- Failed Engine Cooling Thermostat
- Engine Cooling Thermostat harness is open or shorted
- Engine Cooling Thermostat circuit poor electrical connection

Read more: http://engine-codes.com/p0599_bmw.html#ixzz2X92clObS

I think the code reader at Pep Boys is screwed up.

 

Because PepBoys used a $49.95 code reader. Sh*t in, sh*t out. You got just what you paid for, and I suspect you paid nothing.

 

Haha yes i paid nothing so at least I got something even if it was ****. Ill do some more diagnostics on the t-state before I replace since most people are saying its a PITA.

Im just curious where the Cruise Control Circuit High message even comes from, and also in the link you posted which I had read previously, it stats in the "When is the code detected" section that its a p0598 code that is thrown when the T-state faults out, which added to my confusion.


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Haha yes i paid nothing so at least I got something even if it was ****. Ill do some more diagnostics on the t-state before I replace since most people are saying its a PITA.

Im just curious where the Cruise Control Circuit High message even comes from, and also in the link you posted which I had read previously, it stats in the "When is the code detected" section that its a p0598 code that is thrown when the T-state faults out, which added to my confusion.

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When an ECU reports a fault it is required by the EPA to report a generic code, in other words, one which the same code number means the same thing to everybody.

The EPA does not mandate how specific the generic code is, just that a code number be generated. This is what PepBoys got.

What the code number means is entered by the manufacturer of the scan tool. If he misidentifies codes then you get a bad interpretation which is what you got.

A top quality scanner will give you the BMW specific codes. They are far more precise in identifying faults and determining the cause. You didn't get this from PepBoys because they cannot afford to spend good money on a scanner being used by an inexperienced tire changer. If they had an $8,000 scanner being read by an ASE L1 tech with 10 years experience then they wouldn't be doing it for free. Simple as that.

 

My SES light came on the other day, took the car to PepBoys to get the code pulled today. Watched the tech plug the reader in and it read "P0599 Cruise Control Circuit High" After doing research on this and other forums I keep seeing P0599 show up as a "Thermostat Heater Control Circuit High". And everyone is saying to replace thermostat to fix the problem. Which is fine I will do that, but if that's the problem what is all this "Cruise Control Circuit High" talk coming from my BMW? Any clarification would help, I am just confused on why it wouldn't just say Thermostat Heater Control Circuit High in the first place.

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When using a generic OBDII code scanner, the reading is murky, my friend....a dark shroud of ignorance lies between you and what you seek.

You must read BMW proprietary codes -- only then will the truth be revealed! Oh, and the All Seeing Mech says: Replace your thermostat.

.

 

Hahahaha thanks CALWATERBOY


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THanks DSXMachina! I appreciate the in depth response. Everything you said makes perfect sense and I wasn't expecting a whole lot from Pepboys as you stated.

I appreciate everyone taking the time to read my post even if you didn't respond, and for the people who did respond thanks for all of ur knowledge. I am a little more informed and a little less ignorant than I was yesterday.


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THanks DSXMachina! I appreciate the in depth response. Everything you said makes perfect sense and I wasn't expecting a whole lot from Pepboys as you stated.

I appreciate everyone taking the time to read my post even if you didn't respond, and for the people who did respond thanks for all of ur knowledge. I am a little more informed and a little less ignorant than I was yesterday.

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We need your address please. We'll send you a bill. Education ain't free!

 

Your checks are in the mail, I got ur addresses from the NSA


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Your checks are in the mail, I got ur addresses from the NSA

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LOL, good attitude. :thumbup:

Are you planning on changing the t'stat yourself? Good DIY project for which many DIY threads exist. We might be able to offer some genuine help on that job if you get hung up, but the swap should be an easy job.

 

Yes ill be doing the swap myself and I have already read up on the DIYs out there. I prefer to do the repairs on my car so I know they are done right and also saving the money in labor of having a shop to it is always a plus. And of course ill be posting again if I get hung up on anything. Thanks again!


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FYI, what's probably failed is the heater element which is commanded on by the ECU when it senses that you are driving in a...um...spirited fashion and may need to have a lot more cooling, a lot sooner than normal. The element then heats up a wax pellet which expands and forces the thermostat open, rather than waiting for engine heat (via the coolant) to slowly open the t'stat. With that code, and no others, you could drive forever, but it's best to fix it so you're ready for those adrenalin moments.

 

I'm still stunned to read that you took your BMW to Pep Boys for service. :yikes: