2001 lincoln LS V8 Code # 1299

[shorod]

Welcome to the forum!

Have you tried running the DATC self-diagnostics? If not, the procedure is posted elsewhere on the forum. Try performing a search for keywords "DATC self".

-Rod

[rhanson1]

Thanks for the suggestion shorod, but I suspect that my problem is simply the result of air trapped in the heater core. I bought some coolant yesterday to top off the reservoir, and it took 3 quarts. In light of the fact that the entire system capacity is only 11.9 quarts, I have to suspect that my heat problems are related to this. Adding the coolant seems to have helped the heat problem a bit, but it has not entirely solved it. Since the system was so low on coolant, it seems like my first order of business should be bleed out any air that may have entered. I'm hopeful that this will solve my problem. If not, then I will have to move on to other possibilities. Now I need to do a little searching on this forum to figure out the best way to bleed any air out of the cooling system.

[shorod]

Ahhh, that would make sense. Good find.

3.9L engines




Remove the engine fill cap.

3.0L engines


Open the engine air bleed.

Open the heater air bleed.
Add coolant to the degas bottle allowing the system to equalize until no more coolant can be added.

3.0L engines


Close the engine air bleed when coolant begins to escape.

Install the degas bottle cap.
CAUTION: Care must be taken to make sure the accessory drive belt does not become contaminated with engine coolant.

Add as much coolant as possible to the engine fill. The heater air bleed will remain open.
Install the engine fill cap.
Install the engine fill cap until contact is made, then tighten an additional 45 degrees (1/8 turn).
NOTE: The heater air bleed remains open. Start the engine and turn the heater to the MAX position.
Close the heater air bleed when a steady stream of coolant escapes during engine idle.
Allow the engine to idle for five minutes, add coolant to the degas bottle as needed to maintain the cold fill MAX mark.

Open the heater air bleed to release any trapped air and close again.

3.9L engines
Maintain engine speed of 2,000 rpm for 3-5 minutes or until hot air comes from the heater.
Return to idle and verify hot air is still coming from the heater.

3.0L engines
Maintain engine speed of 1,500 rpm for 3-5 minutes or until hot air comes from the heater.
Return to idle and verify hot air is still coming from the heater.

All engines
Set the heater temperature setting to 24°C (75°F) and allow the vehicle to idle for two minutes.
Shut the engine off and allow to cool.
After the engine has cooled, add coolant to the degas bottle to bring the level to the cold fill MAX mark.

-Rod

[rhanson1]

The problem with erratic, insufficient, or no heat with my '04 LS V8 continues. I am stumped, so any suggestions would be appreciated.

Here are the symptoms. The automatic temperature control system works fine for about the first 20 minutes of driving after starting a cold engine. Then the air temperature coming from the vents gradually becomes cooler until they are blowing nothing but cold air. The blower motor ratchets up to full speed because the system knows that the cabin temperature is falling behind the set temperature. As I move the temperature setting up, the air discharge temperature moves up slightly . . . for a few minutes. Then it goes cold again. This procedure continues until I have the temperature setting up to 85 degrees. Eventually the air goes cold even with the ATC set at 85 degrees, even though the cabin temperature is only 55-60 degrees.

If I push the ATC temperature setting from 85 to its maximum setting of 90 degrees, there is suddenly abundant heat, and the heat continues for as long as the temperature is set a 90. As soon as I reduce the temperature setting to 85, the air from the vents goes cold again, even though the cabin temperature is only 60 degrees. The blower motor continues to run at full speed throughout this whole exercise as the system tries desperately to bring the cabin temperature up to the set temperature.

I thought that I had discovered the solution to this problem a few days ago when I noticed that my coolant was very low. I figured that the low coolant level had probably allowed air into the system causing a vapor lock in the heater cores. After adding 3 quarts of coolant and bleeding the system through the heater hose bleed valve next to the coolant reervoir, I figured that my problems were fixed. But it soon became apparent that they weren't.

I have considered the possibility that I may still have air in the cooling system, and that I need to bleed it some more. However, in light of the fact that I can get abundant heat out of the system at any time when I push the temperature setting to 90 degrees, it seems unlikely that the problem could be an air lock in the heater core.

The engine temperature gauges behaves as it always has. After a cold start, the needle moves up to the midway position after a few minutes and stays there. Warm air from the heater comes very fast, as it always has, within a couple of minutes. The problem is that the warm air eventually turns cool. It seems to make no difference whether I'm driving or idling, and racing the engine at 3,000 rpm also seems to have no effect.

I don't know whether this has anything to do with the problem, but I've noticed that the face of the ATC panel on the dash becomes increasingly warm to the touch as the engine runs longer. After a 2-hour drive, it is actually hot to the touch. Is this normal, or is it a sign that something might be wrong with the control panel? Shorad, you suggested in a previous post that I try running the DATC self-diagnostics which I should be able to find by searching the forum. I tried searching but could not find what you were referring to.

Any suggestions would be appreciated. Winter is coming, and I don't want to be driving around here in Maine with no heat. Like I mentioned in a previous post, I took the car to my local Lincoln dealer to service the problem a while ago, and he was totally useless.

[rhanson1]

Rod, I don't if you've had a chance yet read my post above, but I finally found instructions on how to do a DATC self-diagnostic for a 2004 LS. The problem is that I don't know how to interpret the results. I took photos of the results, but I don't know how to attach photos to this post, so I'm giving you a link to an online 2-photo slideshow showing the results. Sorry, but it's the only way I could figure out to show you the info. Let me know if the results offer any clue about my heating problem. [IMG]file:///C:/DOCUME%7E1/Rick/LOCALS%7E1/Temp/moz-screenshot.jpg[/IMG][IMG]file:///C:/DOCUME%7E1/Rick/LOCALS%7E1/Temp/moz-screenshot-1.jpg[/IMG]http://www.photoshow.com/watch/qs5Te4Sx

[rhanson1]

Rod, upon doing further research, I see that results in my photos simply indicate that everything is working properly. I understand that the self-test procedure does a hard reset of the system, so perhaps that will help. I'm running out of possible reasons for my heat problems, so let me know if you have any ideas.

[shorod]

It appears you have a problem with the photo links. It looks like the links to the images are still on your harddrive and I don't find anything at the roxio photoshow link.

What your climate control is doing is almost the exact opposite of what my wife's was doing. On hers, we'd get heat on any setting until we set the controls to 60 degrees, at which time we'd get full cold. Since you get heat with the set point at 90, it sounds like the DCCV is working when it's commanded to open/close, it's just being commanded to close most of the time.

On my wife's, the problem was a bad evaporator air discharge temperature sensor. The sensor was always reading 255 degrees. Maybe yours is reading 0 (or whatever the minimum is). For what it's worth, hers did not have a diagnostic code, but I was able to monitor the sensors and door positions in the datastream mode of my scan tool. I would hope the dealer would have had the capability to do this too.... There are 4 sensors which are all the same part number. I swapped the evap air discharge sensor with the passenger air discharge temp sensor and the functionality of the system seemed to working working fine, so I bought a new sensor (around $22 from the dealer) and all's been well through the remainder of summer and into fall here in Iowa (fairly significant temperature swings). When I bought the sensor, the dealer had to order it and they told me that they've never stocked that part so it must not fail often.

-Rod

[rhanson1]

Rod, I'm not sure what the problem is with the photos. They're not on my hard drive, and the link in this forum works fine for me when I click on it. At any rate, the photos are irrelevant now that I understand that they're simply showing everything as normal.

I had considered the possibility of a bad sensor, but I would think that a bad sensor would cause this problem consistently. The problem that I'm having is erratic - not consistent. Like I said, everything works normally for about the first 20 minutes after I start my car. The only way that a bad sensor could be causing this problem would be if the sensor kept alternating from good to bad. I suppose that's possible, but it seems unlikely. I assume that the problem with your wife's car was consistent in that the vents always spewed heat unless you set the temperature at 60 degrees. With my car, I sometimes can't get heat unless I set the temperature at 90, but other times I can get heat when the temperature is set in the 70's.

By process of elimination, I'm suspecting that I may still have air in my cooling system. That's the only way I can explain its behavior. Perhaps it takes 20 minutes or so for the air to find its way into the heater core - I don't know. What puzzles me about that theory though is that, if air in my heater core is preventing me from getting heat, why do I suddenly get plenty of heat when I move the temperature setting to 90? I'm wondering if perhaps the 90 degree setting is that only one where the DCCV's actually open fully, and the fully open DCCV's somehow allow the coolant to pass through the air lock.

I don't know the answer, but tomorrow I'm going to try a giving the cooling system a really thorough bleed. I bought a plastic hose at the hardware store today. I'm going to open the heater bleed valve and connect one end of the hose to it, then I'm going to stick the other end of the hose into the coolant reservoir. Then I'm going to let the engine run for a half-hour or so with the DATC set at 90. Unless there's something about the LS cooling system that I don't understand, I would think that should remove any air. If that doesn't solve my problem, then I don't know what my next move will be.

I agree with your comment that the Lincoln service people should be able to figure out what's going on and where the problem lies by simply using diagnostic tools. But like I said, they first told me that everything was operating normally, and then after I demonstrated to the mechanic that it wasn't, he seemed puzzled and said that the only thing he could do was to tear my dash apart to see what he could find. His underlying message was, "do you really want to spend that much money on something that doesn't seem to me to be a big deal? I suggest that you learn to live with it."

If I can't figure out this problem myself, then I'll probably either take it back to the dealer and request a different mechanic, or I'll simply find another dealer to take it to. I'll let you know how I make out.

[rhanson1]

Rod, one more doubt about the bad sensor theory. If I had a bad sensor, wouldn't the automatic blower speed slow down (thinking that the temperature had been satisfied)? My doesn't. It continues on high speed trying to bring the cabin up to the proper temperature.

When your wife had the problem with her car, how did her blower speed behave when set on automatic?

[rhanson1]

Sorry for the multiple posts, but my mind keeps working after I make a post, and I think of new arguments to add.

I understand that the LS has separate sensors to maintain separate driver and passenger temperatures. If a sensor went bad on one side, I would think that the other side would still operate properly. With my car however, both the driver side vents and the passenger side vents behave exactly the same. I suppose that I could have intermittently bad sensors on both sides, but that seems like a stretch.

[shorod]

I don't remember how the blower operated with my wife's set to automatic. I seem to rememeber hers blowing full as well because there was such a drastic difference between the set points for driver and passenger sides and the evaporator discharge temp. The evaporator air discharge temp sensor is not different for driver and passenger side. That is the sensor that was reading 255 degrees. I then swapped that sensor with the passenger air discharge temp sensor and the system seemed to function correctly (so it worked once the bad sensor was moved to the passenger air discharge temp position).

If the evap air discharge temp sensor on your car was reading low temp, that might explain why you have exactly the opposite operation as my wifes. The intermittancy could easily be due to a loose connection or a solder joint within the sensor that opens up after a few minutes.

One way to look at it is the cost of the sensor be less than half an hour of the dealer's diagnostic time and will only take about 15 minutes to change out. Plus, if that doesn't fix it, you now how a spare sensor that you can move to the 3 other locations to see if that has an effect.

I don't usually recommend shotgunning parts, but if you don't have access to a profession scan tool at no cost to you, the cost of this shotgunning way outweighs the cost to have a scan tool connected to the system.

You could also check the voltage to the DCCV if you have a fast DMM or better yet, an oscilloscope. If you verify that the DCCV is not being commanded to open at any setting other than 90 degrees, then you know the issue is not solely an air pocket.

-Rod

[rhanson1]

Those sound like great suggestions Rod, and I will definitely give them a try. In regards to checking the voltage signal to the DCCV, why does the DMM have to be "fast"? If I am unable to detect any change in voltage when I change the temperature setting, is that necessarily an indication that the there's a problem with the DATC system, is it possible that the DCCV is controlled by something other than changes in voltage?

I like the idea of swapping the temperature sensors around. That could be the culprit.

Do you agree that the DCCV is likely fine in light of the fact that I can always get heat from the system if I push the temperature setting high enough?

[shorod]

Yeah, I don't think the DCCV is your culprit since it reliably works at the high set point. The DCCV is modulated by voltage from the DATC control unit. When each valve of the DCCV receives battery voltage, it shuts off the flow of coolant. The amount of flow is modulated, so to get a good feel for if the DATC module is commanding the DCCV, you'd want to be able to see the pulse width changes with the DMM. To read something other than "mostly battery voltage" or "no voltage" the meter would need to be pretty fast.

The Red/Orange wire for the DCCV is hot all the time. The Brown/Green wire is for one of the valves and the Brown/Blue wire is for the others. The DCCV switches the ground to modulate the valves. When you set the temperature to 90 degrees, you should read no voltage between either of the brown wires and the Red/Orange wire. That would indicate full coolant flow and that the valve is opening when commanded. However, this doesn't necessarily mean that it can switch fast enough to give the control a new, properly working valve would. That's where the oscilloscope would come in handy, to verify that the valve is not receiving a modulated voltage at lower temperature settings. That being said though, I'd still not recommend changing out the DCCV at this point yet.

-Rod

[rhanson1]

I bled my cooling system for a half-hour like I described, but the system is still doing the same thing. It works fine for the first 15 minutes after a cold start, then the outlet temperature from the vents starts getting progressively colder. The problem begins almost immediately when starting out with warm engine.

I don't know why I didn't think of this before but, when it started blowing cold air today, I opened the hood to check the temperature of the water pipes between the DCCV and the heater cores. They were all so hot that I couldn't touch them. That would seem to confirm theres plenty of hot coolant flowing through the heater cores, but the heat blender door must be closed. It can't be stuck because I get plenty of heat when I push the temperature setting to 90. I also listened carefully with the blower on low and the radio off as I alternately changed the temperature settings back and forth between 60 and 90. I was listening for some sounds of a sticking door, but I couldn't even hear it move. There was nothing but silence as the system alternated between blowing cold air and blowing hot air.

Therefore something must be sending a false signal to the bypass door to make it close up after the system runs for a while. Your suspicions about a bad sensor would seem to make sense (pardon the pun), but I'm not sure how to get at them. I read your post earlier in this thread with instructions about how to access them but, either I don't understand or my car is different. Since my LS is a bit newer than yours, I wonder if the hvac system may be built differently. I don't even see the footwell trim piece that you refer to. When I stick my head under under the dash on the passenger side, I can see the blower motor and where it connects to the air ducts, but that's about the only thing that I can positively identify. Everything else is a mystery.

Do you know exactly what controls the blender door? Is it one of those sensors and, if so, do you know which one? Any idea on how I might get instructions to access the sensors?

Lastly, I was thinking about how ridiculous this is that I'm forced into trying to fix this problem myself. Is there any good reason why this shouldn't be a simple fix for a mechanic who knows what he's doing and has access to all the diagnostic gear, wiring diagrams, and disassembly instructions? Wouldn't the proper diagnostic tools tell him exactly where the problem is without having to rip apart my dash searching for it?

[rhanson1]

Rod, I finally found two of the temperature sensors - the evaporator discharge temperature sensor on the driver's side, and the passenger heater core discharge temperature sensor on the passenger side. I know exactly what each one is because of the DTC's that are thrown out when I disconnect them. What was throwing me off in your previous instructions on how to access them was the removal of a knee panel. On my 2004 LS there are no knee panels in the footwells - it's all open when you stick your head underneath (a cost-saving change, no doubt).

I cannot find the driver heater core discharge temperature sensor. In a previous post, you said it was on the driver's side of the center air plenum near the evaporator discharge temperature sensor. Do you recall if it was upstream or downsteam of that sensor or how far away? I've poked my head around up inside there with a mirror, and I can only see the one sensor.

I'm thinking that the most logical culprit is the evaporator discharge temperature sensor. The reason that I'm less suspicious of either of the 2 heater core discharge temperature sensors is because the drivers side and the passenger side temperatures both behave exactly the same. Both sides blow cold air after the car has run for awhile. Seems like that would require both heater core sensors to go bad at the same time, and that seems unlikely.

The evaporator discharge temperature sensor is also the easiest to access. Nevertheless, since you indicated in a previous post that these sensors are quite inexpensive, I'm thinking that perhaps I should simply replace all 3 instead of poking around up inside there swapping things around. It's not a fun place to work. Do you have a part number?