| Author | Message | ||
| Robert Harsell (Stonefly)
Rating: |
I've got a 93 Freightliner that started showing a check engine light. I've never seen it go on by itself before in 5 years and 500,000 miles of driving. The DDEC scanner at the dealer reads that the trouble is caused by low coolant level. The coolant level is all the way up and engine temp is normal. The light does not go on until the engine is warmed up. It goes on and off a few times and then stays on. I changed the coolant level sensor but the problem remains. I cleaned all the wire connections and made sure the radiator was grounded. It happened after I had an oil change and lube. The mechanic said coolant was about 30% and a little low. He added 16 oz. Penn Cool and the rest water. I had my trailer at the time. I went 20 miles up the Highway and the trouble started. Since then, I've been bobtailing around trying to find out what's wrong. I'm afraid to take a load, get far from home, and have the engine shut down. I've been looking for DDEC II troubleshooting on the web - no luck. | ||
| TWODOGS (Twodogs)
Rating: N/A |
I'd change the sending unit on the water leval indicator | ||
| Sean Welsh (Sean)
Rating: N/A |
Robert, The coolant level sensors are notorious for giving a bad reading periodically, which is usually cured by pulling it out and cleaning it off. Many engines have two different coolant level sensors, one for the DDEC and a separate one for a tell-tale alarm. Make sure you clean or replace the correct sender. If that doesn't fix it, you will need to follow the troubleshooting procedure in the DDEC troubleshooting manual. This information is not on the net -- you will need to spring for the manual in hard copy. Well worth the money. The manual will lead you through checking all signal, voltage, and ground lines between the ECM and the sender. Also, the manual explains how to read out codes without benefit of a reader, which comes in mighty handy in the middle of nowhere. HTH, -Sean | ||
| niles steckbauer (Niles500)
Rating: N/A |
http://www.valleypowersystems.com/ddeccodes.htm http://www.detroitdiesel.com/public/technicianguides/7se390.pdf http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _160.htm http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _162.htm http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _268.htm http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _270.htm http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _266.htm http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _172.htm http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _174.htm http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _176.htm http://www.tpub.com/content/constructiontractors/TM-9-2320-360-20-1/css/TM-9-2320-360-20-1 _178.htm | ||
| Jtng Rating: N/A |
Attaboy Niles! I'm proud of ya'! | ||
| Ed Jewett (Kristinsgrandpa)
Rating: N/A |
Niles you da man!!!!! Thanks, Ed. | ||
| Robert Harsell (Stonefly)
Rating: N/A |
Sean, Thank you. I will try to get the manual. I did pull the sensor out of the surge tank on top of the radiator and clean it. When that didn't work, I installed a new one. I have no idea where another sensor might be located. There have been conflicting clues on this. When the trouble began, hard right turns brought the light on, after the engine had warmed up. Then, in a few hundred yards, the light would go off, and then begin going off and on. This happened a half dozen times, so I don't think it was coincindence. At the dealer, while I was waiting for the service manager to use his ECM device, I noticed that the wire lead going to the ground part of the sensor (held by a small screw into the side of the 11/16" sensor) was loose. When I tightened it, the engine immediately dropped to low idle. I jumped down and got in the truck, and the engine shut-down light had gone on. In a few more seconds, the engine shut down. The service manager gave me the advice of removing the sensor, cleaning it, and making sure that all of the wire and ground connections were good. These things I did. He also told me that his device was reading low engine coolant as the reason for the shutdown. I removed the sensor ground wire and the engine ran, to get me home. Now, I leave that ground wire on, (with the new sensor) and although the yellow check-engine light goes on, the red shut-down light does not, and the engine stays running. Except that once, and only once, when I was braking to turn, the red light flashed for a second, and went off. It appears that now, the only factor in getting the yellow warning is the engine warming to operating temperature. And now the light stays on. I do not know how to read codes out of this engine, which is something I will probably only get out of a manual. I am beginning to suspect that the info given to me by the sercvice manager's ECM device may not be right. Maybe this has only to do with temperature. Thanks to Niles, I downloaded some valuable information about my cooling system. There were some things about scale and additives that may be a part of the problem and its solution. The fact that this happened immediately following the addition of a cooling system additive (16 oz. of Penn Cool) might be a clue. I noticed that when I turned on the key, before starting the engine, the yellow and red light came on as they always have, and are supposed to, until the engine is running. This time, I held in the override button next to the starter button. The yellow and red light went off. Does this indicate that if I experience an engine shut-down, caused by a faulty sensor reading, that I can override it and keep the engine running? This is an important consideration, since I will be weighing almost 80,000 lbs., have an appointment for delivery of refrigerated food, and may be on the middle of the George Washington Bridge into New York City or an equally inopportune location. Earlier today, I bobtailed the tractor for about 40 minutes until the light went on and discovered that the overide does not make the light go out. Hopefully, the override would allow one to drive the truck until the problem is resolved. Thanks again for your help, Robert | ||
| Robert Harsell (Stonefly)
Rating: N/A |
Thanks, Niles. I've had this truck serviced regularly for over half a million miles. I've rplaced altenators, the turbo about 300,000 miles ago, water pump and the like. This is the first trouble I've had that I don't understand. I may find the answer on the websites you mentioned. Robert | ||
| Robert Harsell (Stonefly)
Rating: N/A |
To Twodogs, Is the sending unit something other than the sensor mounted in the surge tank? Robert | ||
| TWODOGS (Twodogs)
Rating: N/A |
same | ||
| Sean Welsh (Sean)
Rating: N/A |
Robert, Wow, a lot of things to answer here. I'll take them in a slightly different order. First, let me say that I also have a DDEC-II and I have experienced (and sometimes still experience) some of these issues -- I know how frustrating they can sometimes be. Due to the complexity of our cooling system, we just can't eliminate all the leaks. Mostly, we have some leakage in very cold weather, at our hose fittings. Generally, these are brass fittings with silicone hoses and stainless clamps. In the cold, the brass shrinks more than the stainless, and small leaks develop between the brass and the hose. The leaks generally go away when the system warms up. The way we know we are running low on coolant is that we get a coolant alarm when making right turns. The reason for this is that our overflow tank is a long, skinny tank mounted horizontally across the back of the coach, and the two low coolant sensors are mounted at the top right of the tank. There is very little delta, a matter of ounces, between the lip of the fill hole, the sight glass, and these sensors when the tank is perfectly level. If we filled our coolant to the correct mark with a level coach, and then leaned the coach perhaps 25 degrees to the left, the senders would be above the coolant level. So it doesn't take much of a drop at all for the sensors to "splash out" on a hard right turn. We have two sensors -- one is connected to a bell in the cockpit, and the other goes to the DDEC ECM. From your description, it sounds like you are experiencing the same situation. How the DDEC responds to "low coolant" signals from the sender is a matter of programming. Most over-the-road applications have the low coolant condition programmed as an "engine stop" situation. This means that when the ECM detects low coolant level, you will get a "Stop Engine" light. Once the stop engine light comes on, you will have a pre-programmed amount of time before the engine shuts down automatically. Also, horsepower will be limited to an emergency quantity while the light is on. Pressing and holding the "Engine Override" button will allow the engine to keep running past the programmed timer. This will allow you to safely drive to the shoulder or other stopping place. This is a dead-man switch -- as soon as it is released, the shutdown sequence will continue. Holding the switch down will also restore full power. The catch is that, unless you know for sure what is causing the error, you may be overriding a more serious condition (e.g. low oil pressure). In our case, when the Stop Engine light comes on during a hard right turn, I hold the override in until the light goes out, then stop when convenient and add coolant. But, to be fair, I have a display on my dash that tells me exactly what error codes the DDEC is showing. By contrast, the "Check Engine" light usually indicates some other code. Since you are experiencing Stop Engine lights, I am assuming that your ECM is programmed for stop engine on low coolant. So the check engine must be a different code. The DDEC sensor has three wires going to it. One of these supplies a +5v signal from the ECM, one provides a ground path back to the ECM, and the other is the "wiper" or signal wire back to the ECM. The Stop Engine (Low Coolant) signal comes when all three wires are working correctly (or so the ECM thinks) and the signal return is below a certain value. However, a Check Engine code can be generated if the ECM detects a problem in the wiring itself. Some of these codes are Coolant Level Sensor High Volt, and Coolant Level Sensor Low Volt. An intermittent problem can cause all three of these codes. Your best bet is to read the codes out as soon as they happen. To read codes out in the field, stop the truck and turn off the ingition. Find your DDEC-II diagnostic connector, which is a rectangular job with 12 pins, probably under the dash. Stick a paper clip or other shorting device between pins A and M (they are labeled on the plastic of the connector in tiny letters -- A and M are right next to each other at one end), then turn the ignition on (but do not crank). The Check Engine light will flash out the codes. For example, four flashes, then a short pause, then three flashes, then a longer pause would be a code 43. After the long pause, other codes may follow in the same manner. When the code numbers start repeating you have seen them all. These codes will tell you where to look next. I did not think the troubleshooting information was on line (actually, it's not supposed to be on-line, but that's another story), but Niles sent you links to some of it. Even though those pages are for construction equipment, which is programmed differently, the basics are the same. You may want to print out the ones asscociated with codes 13, 16, and 43 (CLS low volt, CLS high volt, and low coolant). If the sensor itself is good, and it's clean, and it's sitting in coolant, then my guess is that one of the three signal wires has a problem between the sensor and the ECM. The last thing I will mention is that various "films" can form on the sensor and inhibit its function. This is why removing the sensor and wiping it off often cures the problem. One possibility is that the Penn Cool additive might be causing a film to form, in which case I would say this additive is incompatible with the DDEC system. You might ask Detroit and/or Penn Cool if there is a known problem with this additive. Also, the additive could be interacting with something else in the cooling system, such as a contaminant, perhaps from hard water or something of that nature. Flushing and refilling the system would be the fix for that. I recommend using either pre-mix coolant, or mixing only with distilled or DI water. HTH. -Sean | ||
| Robert Harsell (Stonefly)
Rating: N/A |
Sean, My engine definately is programmed to shut down for low coolant. It has happened several times. The yellow and red light come on together, and in about ten seconds, the engine stops. Adding coolant or water immediately fixes the problem. The delta on my tank is about 2 gallons. My overflow tank is atop the radiator in the front of the truck. It's deep and narrower than the radiator. The coolant level sensor is near the bottom of the tank. The tank is full. What I have now is something else. Engine temperature is right. Oil pressure is right. Both systems are filled to capacity. I don't believe there is any problem with my engine. What worries me the most is that I need to get back to work, and am afraid of the ECM computer shutting me down for an erroneous reason, and leaving me stranded with a customer's freight, the expense of having a fully loaded eighteen wheeler towed a long distance, having to find some other way to get the freight delivered, and then, having to have my truck repaired at a place where I will be pretty much at somebody's mercy. Such are the fears of the owner/operator. Some have gone out of business for less. However, that is a worst case scenario. The information you sent me on the diagnostic pins and the codes, together with what Niles sent, should steer me pretty close to the solution, if not the bulls eye. Also, it is good to know what the override button will and will not do. I have never used it or had occaision to use it. This truck has proved to be one very good investment. It is a 93 Freightliner FLD 120 that I bought in 2000 with 650,000 miles on it. I have driven it about a half million more. It was a fleet truck. I know something of the history. The head has never been off. The tranny and tandems have never been worked on. Only peripheral things have been changed. It's been coast to coast more times than I can count and I have always trusted it to go anywhere and get me back home. It never goes above 200 degrees, even on the steepest climb with a full load on a hot summer day. I drive it like it was a baby, keep it lubed, and in good oil. Even now, it runs strong and efficiently. But a computer...............? I do most of the work on it myself, and it's fitting that I should finally have to learn something about the ECM and its attendant wiring and sensors. However, I grew up on points, plugs and condenser and still find it a little frightening that motor vehicles, be they 4 wheelers, buses, or tractor trailers, are controlled by computer. The first thing to do is flush the cooling system and refill with new coolant and distilled water, as in your last paragraph. The sensor on my tank has only two wires going to it. One goes to ground, and the other to the center of the sensor. If there is a third wire going into the circuit somewhere else, I will have to find it. I greatly appreciate your help. Robert | ||
| Sammy B
Rating: N/A |
Robert, DDEC II also uses a coolant level sensor "module" (CLSM). Small flat black rectangular box - about 3"x1 1/2". A GM style "weatherpack" connector plugs into it. The coolant level sensor (CLS) communicates to the DDEC ECM thru this module.I recommend trying to locate this module and checking the wiring. Best of luck with your troubleshooting. Send an e-mail if you need more info. Sammy | ||
| Paul Ghelli (57shadowdog)
Rating: N/A |
Wow!! with all of that it makes me glad that my 1986 cat. has nothing but a thumb screw on the fuel body to get me home! 1.8000.000 miles and going strong. | ||
| niles steckbauer (Niles500)
Rating: N/A |
Robert - please contact Horizon Coach in Arcadia Fl - (863)-993-1600 - Ace (tell them that) had a very similar problem w/ his ddec and left it with them after Bussin 2005 - sending unit was the culprit - see if they can talk you through it - Niles | ||
| niles steckbauer (Niles500)
Rating: N/A |
UPDATE - Robert - ACE offered the following in contact w/ me - verified the problem in his case (and maybe yours) was the 'sending unit going to the DDEC' and NOT the sensor - he also said if your rear 3 way start switch works like his did , you might be able to start and run it in the "off" position - that's how he got to Arcadia - hope that helps - Niles | ||
| Sammy B
Rating: N/A |
Robert, the Coolant Level Sensor Module that I mentioned previously is the same as "the 'sending unit going to the DDEC'. Niles has gotten some great info from Ace for you. Let me know if you need any help with it. Best of luck. Sammy | ||
| niles steckbauer (Niles500)
Rating: N/A |
Thanks Sammy for clarifying that - next time I'll try and use the proper terminology - sorry if I confused any one - Niles | ||
| niles steckbauer (Niles500)
Rating: N/A |
UPDATE 2 - Ace has given me a better description of the problem he experienced - HTH - Niles There IS a low coolant level sensor and it is seperate from the sending unit. Mine is tucked up in the side electrical compartment on Left Rear inside the inner door! It is up under the floor and hard to find. It's a black box with a wire harness going to it! IT IS NOT THE SAME AS THE SENDING UNIT! | ||
| Robert Harsell (Stonefly)
Rating: N/A |
Thanks to everyone for their help. I never had occaison before to read codes out of the engine. I found the check engine button, held it, and discovered that I had ten codes blinking out. The low coolant level was only one of them. The info I had gotten from the service manager that engine shut-down was from low coolant level was probably right. But he never did tell me when that shut-down was. I later found out that codes stay in the ECM until they're removed. In that case, for me, it's over five years. I had the codes deleted from the ECM so that only the current problem would show. I had the cooling system flushed and filled with new coolant plus distilled water. On the way home, the check engine light came on again. With the check engine button held in, only code 14 read out. Code 14 is oil or coolant temperature sensor (OTS or CTS) voltage high. Thanks, Niles, for the code information. If the ECM is reading things correctly, there's trouble in the wiring between the sensors and the ECM, or a bad sensor. My engine does not have an oil temperature guage, but I figure it may have a OTS for the ECM. I bought an ECM coolant temperature sensor, after finding out that there are two coolant temperature sensors, one for the guage and one for the ECM. I could not find anywhere on the engine a sensor that looks anything like the one I bought. The engine is a 12.7 liter 430/470 Detroit. If anyone knows where that sensor might be located, I'd sure like to know. There's one on the right rear of the cylinder head with one wire going to it, but I think that one is for the guage. The one for the ECM sensor gets a plug with two connections. I asked the mechanic to program the ECM to not shut down the engine. I hope he did. Until the problem is resolved, I'll have to do without that engine safety feature. I would like to be able to do this type of job myself. Is there software (for non-dealers) that can be used with a laptop connected to the diagnostic plug? I will also look for the black box module and harness (CLSM). The read-out on the mechanic's computer said low coolant 117 times. I know that my engine coolant has not been low that many times, so there is still an intermittent problem with coolant level readings. Robert | ||
| Sammy
Rating: N/A |
You've got a 12.7 litre Series 60 in your truck. You might not have a CTS, only an OTS (oil temp sensor).It depend on the programming of your engine ECM. I've troubleshot and repaired all kinds of diagnostic problems on Series 60 with DDECII and DDECIII in all kinds of coaches. I might be able to help you. I have over 20 yrs of experience with Detroits. I don't know everything, but will be glad to try to help you .I've got my own diagnostic tools with all software needed. Where are you located?? | ||
| Macgyver (91flyer)
Rating: N/A |
I know this weighs in a little late... but, I had a problem with my coolant level sensor too... but unfortunately, I was out in the middle of nowhere with no money for a tow... I had to talk to the manufacturer and have one of the techs walk me through everything. He was very helpful and I kept him on the phone for over an hour..... It turned out that it was, in fact, the level sensor. I had previously been told by another shop that with the DDEC-III system I had, that the sensor could NOT be bypassed. I was told this by 3 shops before talking to the manufacturer. All three wanted me to tow the bus into their shop so they could run diags on it... In talking with the tech at the manufacturer, he told me to cross the two wires from the sensor and ground it. My problem should go away until I can either replace the sensor, or clean it properly... I did it, and it went away... It's still crossed and grounded for the time being. I had another issue come up later on, and there was a new code... The oil sensor was tripping the code... I took off the plug and it was all nice and green underneath... Cleaned the contacts, put some of that nice contact gel in there and everything has worked fine since... My point is... So far, all of the problems I've had have been electrical malfunctions, and none of which were actually serious... yours is probably a corroded contact, a loose wire or even just a bad sensor. But as I've said before... I'm not a mechanic. I'm not an expert. This is only my own personal limited experience.  -Mac | ||
| Robert Harsell (Stonefly)
Rating: N/A |
Thanks Mac Your information does not weigh in late. Robert | ||
| Robert Harsell (Stonefly)
Rating: N/A |
Thanks Sammy, At this point it's a good guess that there is no CTS on my engine, other than the one for the guage. I'm located in Greenville, VA. Greenville is about midway between Roanoke and Harrisonburg. If there is no CTS for my ECM, and the yellow chk. eng. light goes on only when the engine is warmed up, does that give any clues? Also, do you know where the oil temperature senders are on the engine. There should be one for pressure and one for temperature. Is this correct? For today, I'm going to follow Mac's advice. I'll check the contacts on every sensor that I can find. Again, Thank You, Robert | ||
| Sammy
Rating: N/A |
Robert,don't give up yet. I'll send you a picture with all the sensors and their locations. Yes, there are 2 different sensors - Oil Pressure Sensor, and Oil Temp Sensor. The OTS is large and has a 3 terminal connector. The OPS is small and has a 2 terminal connector. Both are located on the drivers side of the block, towards the rear of the engine.If you have a Coolant Temp Sensor it would probably thread into the thermostat housing. The Coolant Temp, Oil Temp, and Fuel temp sensors are the same. Same part number for all 3. Did the dealer print out anything for you besides the codes when they had their scan tool hooked up to your truck? By the way, I'm located in N.Y. on Long Island. | ||
| Robert Harsell (Stonefly)
Rating: N/A |
Thanks for the pictures of the sensor locations, Sammy. You see how on the picture they show the wires running between the oil pressure and oil temperature sensor? On my truck, those wires completely conceal the temp. sensor. Not only that but they won't hardly budge, and there's an oil line and air line passing across. They don't move either, without a whole lot of disconnecting. Add a coating of grime. If I didn't know it was there, I'd have never spotted that OTS. True to Freightliner's standard operating procedure, they put things where an ant couldn't reach, and if he could, there's no room for him to turn a wrench. But guess what? There was enough room for me to slip my pocketknife along the back of the sensor to hold the clip away, and with my pinky, pull off the connector. After I quit cussing, I saw the two wires going to the sensor connector, both of them chafed almost completely through. Nothing left but a little insulation. Now I have a soldering job to do in a very difficult location. But that's not new to me after owning Freightliners for eight years. I'll get back to you after I solder those wires and give the truck a test run. Robert | ||
| Sammy
Rating: N/A |
Robert, I think you might be on to something. Great find, good pair of eyes. let me know if you need another connector with leads on it. I can put one together for you so you'll have a little more to work with. Sammy | ||
| Robert Harsell (Stonefly)
Rating: N/A |
Sammy, those chafed wires were causing the problem. Thanks for your help. Truth being told, the way that sensor was buried back there above the starter, I'd have never spotted it. That picture was worth more than a thousand words. Now I've got a code 42, which is for the Synchronous Reference Sensor. Again, thanks to Niles for the code info. That code must have come up when I pulled the sensor out to see what it did. That was before I got the pictures of the sensor locations. I wish I had a way to erase those codes myself. The sensor was too difficult to reach with a soldering iron. But I did manage to strip the wires and clean them. I sprayed them with starting fluid, then wiped them with a clean rag to get rid of all grease. Then I used splicers, making sure they were crimped good. I pull tested the splices and then put silicone gasket material around the ends of the splicers. I've got a 13 year old refrigerated trailer that has lights going out all over it on a fairly regular basis. Three out of four times, the cause is copper wire being exposed to the elements. The copper turns to that pretty green powder that was giving Mr. Macgyver the problems on his bus. (The problem did turn out to be in the wiring.) Any time I use a crimp splicer I seal the ends. I took a ride in the countryside for a couple of hours - no trouble. Thanks again to Sean. I did order the DDEC II Troubleshooting Guide 6SE489. It was back-ordered and will take a few weeks. I see buses in my travels throughout the USA. From now on when I see one I'll think of all y'all. I found a lot more good advice on this website than I got from dealers, mechanics, and other truck drivers. Robert | ||
| Sammy
Rating: N/A |
Robert, very glad to have been able to help you. If you ever have any more trouble in the future, just send me an e-mail - torquemup@msn.com Next trip up this way,if you're coming out to Long Island, gimme a shout. I'll clear the codes for you and give you a diagnostic data print out for your reference. Best of luck. Sammy |
