Overheating or...? P1299 code October 01, 2016, 12:00:32 am I've got a problem. I started on a cross-country trip this afternoon, but after three hours of driving my low oil light came on, as well as the check engine light. I pulled over immediately. My UltraGauge showed a P1299 code: "Cylinder head temperature sensor detected engine overheating condition."I had checked the oil before leaving, and it was in the middle of the dipstick's range. After stopping, I should have rechecked the oil level before doing anything, but instead I added a quart and then checked. The oil level was just at the top of the range, so it didn't seem as if it had been low, despite the low oil warning light.After about twenty minutes I restarted the engine, and the low oil light was off. I reset the engine code and got back on the road, but after ten minutes or so the oil and check engine lights came back on again, and I pulled over again. Rechecked oil level; still full. Same P1299 code.This time when I looked under the hood, I noticed that some coolant had overflowed the recycling canister and splashed onto the fusebox cover. Yet the engine temperature, which I watch on the UltraGauge, had never gone above 210-215° F., which is pretty typical for this rig.One more piece of info: as far as I can tell, the engine did not go into "limp mode," which I understand limits one to about 30 mph max. There was some loss of power, but I was still rolling along at 60 until I pulled over.For what it's worth, something similar happened a month or so back: low-oil light and P1299 code. That time I pulled over and after adding a quart, cleared the code and drove another 500+ miles without further incident. I've drive a couple thousand miles since then with no problems... until tonight. And the problem tonight didn't appear until I'd already driven 140+ miles and was headed downhill from Flagstaff. It's not hot, I'm staying at about 60 mph, and I'm not stressing the engine. in fact, I'm towing a 1,500-pound cargo trailer instead of my 3,600-pound car, so this is less stress than usual.So what's going on? Is my engine really reheating? Is the cylinder head temperature sensor giving false readings?I'm currently sitting by the roadside outside of Flagstaff, researching the problem before deciding either to try to proceed slowly to Winslow, or to call Coach-Net and get towed back to Flagstaff. Any suggestions will be gratefully received! 1 Likes
Re: Overheating or...? P1299 code Reply #1 – October 01, 2016, 12:10:51 am Dang Andy ... I so sorry to hear this. After a quick google search:1. Possible causes - Low engine coolant2. Faulty Cylinder Head Temperature Sensor3. Cylinder Head Temperature Sensor harness is open or shorted4. Cylinder Head Temperature Sensor circuit poor electrical connection You've eliminated at least #1. I continue to search and see if I can discover anything that might be helpful to you.One more item ... a cut & paste which might help if the engine is actually not hot.This code indicates that the engine cylinder head temperature sensor indicates the truck is overheating and going into a fail safe strategy. You need to first check the coolant level, if it is low then look for an external leak somewhere. If the level is ok then it could just need a thermostat replacement. If the engine actually does not even seem to be overheating or hot then it could be the sensor giving it a false reading.Additional Information. Andy, there is very long thread on this topic at false overheat indication code P1299 - Ford Truck Enthusiasts Forums with several solutions to include a plugged radiator, bad radiator hose, and various faulty sensors. Hope this additional information helps. 1 Likes
Re: Overheating or...? P1299 code Reply #2 – October 01, 2016, 12:54:08 am Many thanks for the quick response! I've pulled over at a deserted Shell station near Winona, AZ. Fortunately it was only a couple of miles from where I was pulled over to the exit, and I had no further warning lights or codes while driving here. I'll spend the night here and then troubleshoot tomorrow. At worst, I can get Coach-Net to tow me the 15 miles or so back to Flagstaff, where there's sure to be a place that can work on this rig. (Anybody have any recommendations?) Too bad it's the weekend, though; that could make matters more difficult."there is very long thread on this topic at false overheat indication code P1299 - Ford Truck Enthusiasts Forums with several solutions to include a plugged radiator, bad radiator hose, and various faulty sensors."Yes, I read a fair amount of that thread while stopped on the shoulder. (It seems to mostly refer to V6 in Ford's F150 trucks, but the symptoms sounded awfully familiar to what I've seen.) I should have mentioned that the coolant level was about an inch about the "cold level" mark in the tank--which I gather is normal for a engine that has been running for awhile--so the problem isn't low coolant. If anything, the spilled coolant o the under-hood fusebox (which is adjacent to the tank) would seem to suggest too much coolant. (Or possibly overheating, but again, the engine temps weren't any higher than I usually see.)I see no evidence of a radiator-hose leakage or low coolant, but a plugged radiator is a possibility--there's some sludgy-looking stuff at the bottom of my coolant tank, which makes me wonder what's in the radiator. I had been planning to have the cooling system flushed and hoses replaced this winter; guess I should have done it sooner!It could be a bad thermostat. And a faulty cylinder head temperature sensor is also possible--I have no way to test that, but from what I've read, it has been known to happen. But the apparent coolant overflow worries me--that's never happened before. I should add that the oil is not milky, so I don't think it's a blown head gasket. 1 Likes
Re: Overheating or...? P1299 code Reply #3 – October 01, 2016, 01:04:36 am In my experience, a blown head gasket would result in an obviously HOT engine and your engine isn't HOT. One person reported that the error code disappeared after replacing the old and worn radiator cap. So let's hope it's something simple like that. Since I have fast and unlimited Internet, I'll search for recommended places in Flagstaff. A little later ...I found strong recommendations for Flagstaff Auto Repair at 928-526-9159 at 3830 E Huntington Dr, Ste 9, Flagstaff, AZ 86004. The average Yelp rating was 4.8 based on 48 reviews.I also found favorable Yelp reviews for Babbit Ford at 918-774-5063 at 11 N Verde St. ,Flagstaff, AZ 86001. At least with Ford, their repairs have a warranty that could help further down the road.I didn't look for any RV repair business which may not be of great help with this problem. It's 12:20 AM and so I'm signing off, but I'll check back during my regular middle of the night stroll. Take care Andy Baird. 1 Likes
Re: Overheating or...? P1299 code Reply #4 – October 01, 2016, 01:26:13 am Plus one on the radiator cap- though it may not be that simple, many overlook replacing caps when they work on the system. If the spring is weak it will release coolant at lower pressure. Good luck! 1 Likes
Re: Overheating or...? P1299 code Reply #5 – October 01, 2016, 01:29:52 am Spent the last hour researching this with no firm cures found.So here is my suggestion.Verify the temperature reading, on the Ultra Gauge, is accurate. Shoot your infrared thermometer at the thermostat housing, after warming the engine. It should be close to what the gauge indicates.If OK, I would suspect a bad connection or ground. Pull the doghouse and renew or at least wiggle every connector you can find.Find the engine and chassis grounds and renew them. I have found bad grounds to be the cause of many mysterious problems like this.Larry 1 Likes
Re: Overheating or...? P1299 code Reply #6 – October 01, 2016, 01:40:27 am If the temperature of the engine is the same as what is shown on the Ultra Gauge, the sensor is probably fine. Since there is only one temp sensor, then the problem is most likely electrical.Computers (ECM) very rarely go bad, it is the absolute last thing to replace.Before doing anything else, do verify that the cooling system is OK.Larry 1 Likes
Re: Overheating or...? P1299 code Reply #7 – October 01, 2016, 02:49:31 am First I have to say: this group is amazing! Within ten minutes after I posted, Ed responded with solid information, then followed up with more links and service recommendations. Larry, you spent an hour researching and came up with specific troubleshooting ideas that I will put into practice tomorrow. Paul, you pointed out an often-overlooked source of trouble in older engines. My 2003 rig doesn't have a radiator cap, but I know that other members will benefit from your tip. All this late on a Friday night, in the space of a little over an hour!At this point I don't have much to add to what I said earlier, because I'll wait until morning to do further testing. There are houses nearby, and I don't want to wake up the neighbors. To summarize the general picture: a oil-pressure earning light and a P1299 (cylinder head overheating) code from the engine computer, occurring after several hours of driving and then recurring a few miles down the road. Engine tenepratures around 210-215° F., as has been typical in this rig for the past two years. (They went up about 10° after I had a larger transmission cooler added in 2014.) No 30 mph "limp mode," as far as I can tell. (I have experienced that mode once, with a "lean left bank" code, and it's impossible to ignore.) No evidence of low coolant, but some coolant overflow. Oh, there is one other thing, and this could open a whole can of worms: last month I found and cleaned out a good-sized rodent nest in the area directly below the coolant reservoir. There was no evidence of coolant leakage there, and as I said, my coolant level is not low now, but we all know that rodents can chew through all sorts of things, including sensor wires.The problem with that idea, though, is that after cleaning it out, I drove several hundred miles without a sign of trouble. And tonight, the rig ran fine for three hours, and only then suddenly started throwing codes. If a wire or hose had been chewed through, one would expect it to malfunction long before now. I'll take a closer look at that area tomorrow by daylight, but for now it seems a weak hypothesis.I'll keep the group posted on what I find out. 1 Likes
Re: Overheating or...? P1299 code Reply #8 – October 01, 2016, 11:23:57 am Andy,Perhaps you found this already but here's a video on YouTube that may help.https://youtu.be/0f-zaQJsg2wBest of luck my friend.Kent 1 Likes
Re: Overheating or...? P1299 code Reply #9 – October 01, 2016, 11:35:15 am Andy,And then there was this one. Different engine but an interesting corollary...https://youtu.be/7Xl00o_BoZYKent 1 Likes
Re: Overheating or...? P1299 code Reply #10 – October 01, 2016, 02:33:07 pm Could be a vacuum leak in one or more hoses caused by rodent activity.Thus not allowing a sensor to operate correctly. Does it idle well?Babbitt Ford in Flagstaff worked on my 96 many years ago when I had the rodents get into mine. 1 Likes
Re: Overheating or...? P1299 code Reply #11 – October 02, 2016, 12:21:43 am Many thanks, Kent--those videos were very helpful!Since things settled down today, and since it was Saturday morning with no shops open for two days (and then maybe busy), I decided to press on and in the process, gather more clues.One idea (thanks, Larry!) was to wait for the indicated (via ODBII reader) temperature to show 250º or so, and then quickly pull over and measure the thermostat housing using a contactless IR thermometer—to see if it was actually high, or just reading high. But each of the 2-3 times it spiked I were not able to pull over right away (guard rail, etc.) And the spikes only last a few seconds: for example, this afternoon I saw the temperature spike from 221° to 258° in less than twenty seconds, then fall back to 221° in the same amount of time. Almost forty degrees in just twenty seconds?? It’s hard to believe that a mass of metal like the V10 engine could heat up and cool down that fast. That makes me think the indicated temperatures, at least when spiking, are false.At any rate, here are the current ideas and factors, summarized, for those who are playing along at home (and everyone's input has been very valuable and appreciated — in information, ideas, and camaraderie).If the high temps are real:1) Air bubble(s) in the cooling system. The idea is that as they pass through the engine, that leads to temperature spikes. Arguing in favor of this, a cooling hose was (purposely) cut during the installation of a heater valve a month or so back. On the other hand, others who have installed this valve have not burped their systems, and the hose is quite high up in the system (near the firewall leading to the heater core). Another "con" to this theory is that the oil light/check engine light came on during the "warning lights and check engine light” phase. Not sure that would happen with just simple air in the cooling system. I also think I have read that in this case the heater doesn't put out very warm air even when the engine is spiking. The heater today seemed normal.Oh, and another "negative" to this idea is that when the temp is spiking, the cooling fan doesn't come on. And yet I know it has been functioning at certain times in the recent past, and has its own thermostat, independent of the normal temp sensor. If the engine really were getting so hot, wouldn't the "jet engine" noise be coming on? And finally, why would it run fine for hundreds of miles in between episodes? Where would these bubbles be going then? (Not saying there may not be reasons, but just outlining my thinking out loud.)2) Thermostat sticking open or closed. The symptoms of this match mys (spiking temps, especially within 15 minutes of starting, but not always; plus some coolant overflow). But would this be intermittent? Seems as if when I've heard of a thermostat failing, it doesn't come back to life again. Also, would that lead to the check engine and oil lights?3) Loss of radiator performance (clog, etc.). But then why can it run for hundreds of miles and be fine?If the high temps aren't real (or mostly not real):1) Failed or intermittently failing cylinder head temp sensor/sensor harness. This seems like it could account for the false temp readings (if they are, indeed, false). Also the check engine light and oil light apparently come on when this fails. And there was a mouse nest under the hood just before this problem first occurred (although not right where the sensor is). A failing harness could certainly be intermittent. But then why would anti-freeze, albeit only a small amount, have come out of the de-gas bottle?There is a slight possibility the cap was not fully tightened. After this afternoon's indicated temp spikes, and retightening the lid (not that it seemed loose), no more antifreeze was seen leaking. Also, when leaping out today not long after a 258º temp spike, the max temp seen on the IR thermometer was 176º. But it took a bit of time to pull over, jump out, and plus the indicated temp had already gone down to 220º or so by then (the spikes come and go quickly).2) A combo problem making it hard to diagnose. For example (thus is my best guess at present):A failing cylinder head sensor or wiring, plus a radiator that may be *slightly* compromised (because the engine started running about ten degrees hotter than previously, some time ago), plus a coolant mixture that is slightly coolant-rich (more than 50/50 coolant/water), because I had stupidly topped it off with straight coolant after that valve installation I mentioned.Bottom line: on the assumption that the spikes are probably not real, I’m going to continue my trip, watching the temperature like a hawk. I’m now carrying a spare thermostat, so if that turns out to be a problem, I can replace it. And I have a spare cylinder head temp sensor, even though I can’t install it myself.And as mentioned before, when I get back I plan to have the whole cooling system flushed and re-plumbed.I’ll keep you posted! 1 Likes
Re: Overheating or...? P1299 code Reply #12 – October 02, 2016, 01:02:58 am Safe travels Andy. Keeping a cool head at this point seems only fitting. Kent 1 Likes
Re: Overheating or...? P1299 code Reply #13 – October 02, 2016, 02:57:31 pm I carry this cheap thermometer with my permanent on-board took kit:Amazon.com: BAFX Products® - Non Contact - Infrared (IR) Thermometer (-58F -...I had some coolant issues a few years back on our G30. It ultimately came down to thoroughly flushing the entire system, replacing a couple of hoses, and replacing the thermostat + radiator cap. Over time we replaced the serpentine belt & A/C unit, with the result that the engine runs even better.One thing that I haven't seen mentioned is whether or not you've checked the state/charge of your truck battery. Even if it's showing that it's fully charged, if it's not actually holding a charge, then your alternator is probably working over-time trying to keep it charged.This happened to us - we only use our rig a few times/month, so it sits for weeks at a time. The 36-48 month battery was 39 mos old, but lack of use really degraded the battery. We replaced the battery (I go out now once/week to start and let the engine run for 10 minutes) and make sure both our truck & coach batteries are fully charged 100% before we take off. This seems to have worked to help the engine even more, as the alternator has to barely spin to supply the operating electrical components running while underway. 1 Likes As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Overheating or...? P1299 code Reply #14 – October 02, 2016, 10:20:31 pm Thanks for the suggestions, "SNERF". I do carry a couple of IR thermometers similar to yours, and as mentioned in my long post yesterday, I used it to check the engine block temperature. Less than a minute after the indicated temperature had spiked to 258° F., I couldn't see anything higher than 176° with the IR thermometer when scanning the general area of the thermostat.In addition, the engine fan was not running when these supposed temperature spikes occurred. Since the fan has its own independent thermostatic control, that suggests the supposed spikes were not real. If they had been, the fan would have been roaring away.In any event, I drove a couple hundred more miles today without any elevated temperatures, warning lights, or codes. So I'm going to assume that the problem was with the cylinder head temperature sensor, rather than a real mechanical problem, and keep going.I can check the engine battery, but it's a fairly new hefty AGM, so it seems unlikely that it would cause the kind of temperature indications I've been seeing without a lot of other problems also showing up. 1 Likes
Re: Overheating or...? P1299 code Reply #15 – October 03, 2016, 02:33:20 pm Always nice to hear a happy resolution - having car problems while on the road has go to be one of the more stressful events. Are you going to replace any of your sensors? The prices dropped so low on our old chassis platform ('93 EFI 454), that I ended up replacing every single sensor (8-9 total) for a fraction of what they would have normally cost a decade earlier. 1 Likes
Re: Overheating or...? P1299 code Reply #16 – October 03, 2016, 04:53:46 pm We just hope that when we're traveling, that we end up camping next to Andy Baird ... home to the RV Hardware Store. We're saving all our difficult LD "To-Do" Projects and then heading towards Baird_Land! 3 Likes
Re: Overheating or...? P1299 code Reply #17 – October 04, 2016, 09:06:32 am "wondering how they look today as an "after", and how they look from a whole coach POV. "Well, I'm certainly going to have the cylinder head sensor replaced, since I suspect that is the cause of most of my problems. (Not all, because the thermostat could also be involved, and I suspect that the radiator may not be at its best.) Other sensors? I dunno. Hadn't really thought about it, but maybe I should. Anybody have any suggestions for sensors that should be replaced on a 13-year-old engine? 1 Likes
Re: Overheating or...? P1299 code Reply #18 – October 04, 2016, 10:43:52 am I like Larry's idea of also checking all grounds and connections to all sensors. I remember working on early VW electronic fuel injection systems in the 70s, the grounds and good connections to all of the sensors are important, one bad one could start and bring the whole system down. Best of Luck to you! ~Liam 98 - 26.5 MB 1 Likes
Re: Overheating or...? P1299 code Reply #19 – October 04, 2016, 11:14:22 am I wouldn't just start throwing sensors in. That would probably be a waste of time and money. You have the Ultra Gauge that will tell you when something isn't right. Rely on that to tell which sensors should be replaced.When the rodents got into mine, it took 2 efforts to find all the wires and hoses they gnawed on, it was 2 weeks before other things that got attacked started to fail. It is often hard to see all the places the little bastards get into so finding all the problems isn't easy.
Re: Overheating or...? P1299 code Reply #20 – October 04, 2016, 12:01:27 pm Quote from: Jota - October 04, 2016, 11:14:22 amI wouldn't just start throwing sensors in. That would probably be a waste of time and money. You have the Ultra Gauge that will tell you when something isn't right. Rely on that to tell which sensors should be replaced.Unfortunately, a simple reader, like the Ultra Gauge or a SmartGauge, can only read the Check Engine Code (CEL) number. The CELs do not necessarily tell what part is bad, only that there is a problem. A P1299 could be caused by many things, not just the temperature sensor . While researching this I found many similar cases where the sensor was replaced, without solving the problem. The engine's computer (ECM) cannot distinguish between a bad sensor and a poor connection, when setting a code.A professional grade scanner can view and record the various sensors in action.As for replacing other sensors preemptively, it may not prevent future problems and may lead to one. OEM parts are usually as good or better than the replacement parts. Try to stick to OEM sensors, whenever possible. I can remember next to no reported cases of defective sensors, on the forum, through the years, with the exception of O2 sensors. If you do need to replace a O2 sensor, stick with ones from Motorcraft, NTK or Bosch.Larry 2 Likes
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