-
Check Engine Light – 1990 8V92T
So, I have just gone through a problem with the Check Trans light which seems to be fixed. At the same time the check engine light came on as well. Towed to Clarke Power Service in Greensboro, NC. While there I also requested other services which were not done.
Back to the Check Engine light. This was one of the requested repair items. When I started up in preparation to leave, the light had been off but came back on as I exited the driveway. The codes were read during service and did not show any active codes. The coolant level in the surge tank was where it has been for the last 9 years. The tech added anti-freeze to the surge tank and would have filled it to overflowing had I not stopped him. Well the light went out again when the engine was started. This time I got about 5 miles away from the facility and the light came on again. Being unhappy with this repair experience, I drove on. Some miles later the light went off. More miles and it was on again. It finally went off and stayed off for the remaining trip to storage.
Last Saturday I went to the bus to do some other work. Being curious, I started the engine and there was the check engine light shining in my face. I’ll be taking a ride on Sunday and am seeking anyone who has had a similar experience to share their solution. I suspect it is a sensor that is approaching, if not already at, a hard failed condition. Yes, I checked the oil level, its on the mark. The tech filled the surge tank so I don’t see the low water sensor as being the problem. Wondering if I disconnect the wires from the low water sensor mounted on the side of the surge tank if that would extinguish the Check Engine light? If it did then to me that would point to a failed low water sensor.
Does anyone out there in PC land have knowledge on a 1990 8V92 DDEC II engine where other sensors are that would illuminate the Check Engine light and not trigger the Engine Shut Down light as well?
Thanks is advance for any and all suggestions. I have a trip to Nashville coming up in early April and would like to solve the problem before the trip.
-
18 Replies
-
Will,
A couple of things that might help you. First, understand a check engine light does not mean to stop. You can drive with that condition because it will not threaten the engine or its operation. A stop engine light is another matter and that means stop driving and turn the engine off. If you choose to ignore that the computer will shut it down for you.
Getting back to your issue. First determine how you can flash the codes. I cannot tell you the procedure on your coach but there is a way. Prevost can help you if needed. Some of the kids now at Prevost will go foggy because they can’t do anything without the computer plugged in, but some of the older guys can tell you how to do it. On my DDEC I coach I put a jumper between two of the pins on the reader plug (I forgot which ones) and the code would beep on the alarm and the light on the dash would flash the code. Some require inputs like turning on the key and mashing the acclerator 3 times (I made that up).
Once you know the code you have some direction to chasing the problem. I would surmise based on the coach age and your description that the sensors might be OK, but age and corrosion may have created a grounding issue. That is why the codes will help so you don’t have to clean and tighten every ground on the coach. It may be a more serious issue like the ECM beginning to fail, or it could be as simple as the pins in the connector needing a little exercise to get a clean connection.
Good luck. BTW, I would ask the dealer that did not do the work to resolve this to have a guy with his reader or computer plugged in riding with you so he can read the codes so you don’t have to mess with it. On their nickle by the way.
-
outside open the lower door under the driver’s seat. There you will see a location where the tech’s attach their computer. If you move the switch there to ATEC Test mode, your check engine light will flash you the code. If you don’t have the codes, let me know and I’ll dig mine up. This also works for the check transmission.
-
Below are what I have for the engine error codes for a DDEC II system.
-
Transmission Error Codes for a DDEC II
-
On a similar note, I had an error code for the speed sensor on my transmission flashing. I took it to the “experts” and they told me that the speed sensor was loose. When on the farm in Montana, I decided to replace the speed sensor. I had to chisel the thing out of the transmission it was so corroded in.
Turned out that up where the transmission module is (in the bottom door under the driver seat), my relays were not contacting properly. Once I moved the relays around a bit, I have never seen that error code again. Would have saved me a tow and a flight back to pick up the bus after the experts fixed the issue.
-
Yes, read the code(s). I can tell you that disconnecting the wires on the coolant level sensor will not bypass it. If recollection serves, I had to connect mine together (which I accomplished by putting both wires on one terminal of the sensor) to bypass a failed coolant level module.
-
Wow, that is some really good feedback. Now I have some fun ahead of me. I had no idea how to get codes and now I do. Topped off by now having entire listings of both Engine Codes and Tranny Codes.
I know its been said before, but it bears saying again, This Prevost Community bunch is tops in my book too. I hope to see some of you out on the road this season.
Travel safe to all. Now the fun starts tomorrow.
Will
-
Will,
I think you are in your bus for the long term. That being the case you might want to piece together via ebay or other sites the components that will enable you to not only read your own codes, but watch all engine operating parameters in real tilme. I have obtained readers such as the one below, with software for my engine, transmission and the ABS brakes, and find it well worth the inverstment. I have less than $1000 in mine with software.
-
Will,
If yours is a DEC II I have the entire DEC troubleshooting manual for the 8V92. Provides the diagnostic steps for each code. Flash your codes using the test switch in the steering bay and post them. I’ll find a way to get you the right pages.
-
Joe,
My first chance to flash the codes will either be late Saturday or sometime on Sunday. I see I have to update my email address too since I just finished a nice message back and it was using my abandoned TWC account. We split with TWC last July when I got back from Seattle, Washington and I was locked out of my account. I’ll go into my Profile and update it. No problems at all with the gmail.com address. I hated to stop using steelrails as I am a train fan and with the TWC account being nc.rr.com the handle was a perfect fit.
I’ll get back with you sometime this weekend.
Thanks!
-
Will,
No problem, I’m headed to Vonore Friday the big seminar. Send those codes and I’ll get the A team on reading the book.
-
Joe,
Flashed codes this morning. Code 13 appears to be the culprit. That would be a Coolant Sensor Lo Volt.
-
I’ll get you some info Monday. Seminar finished a little early and I drove back this afternoon and didn’t see you posted the code until now.
-
will,
i came to work today without getting the dec 2 troubleshooting book off the coach so I can scan the pages for you. I’ll get It tonight.
if if you want to try something easy, get some electronic cleaner and spray (circuit deenergized) both male and female parts. Let it dry a couple of minutes and then put dielectric grease on the connector going to the level sensor. I bet that connector is corroded.
Did you see my post about about the compressed smoke? Never take electrical advise from me! just saying…..
-
I tried to search for the location of the 8V92 temperature sensor location, but could not find any picture or diagram depicting it. I did run across this and it has some information that might be helpful. I have to believe there is a location pictured somewhere, but I could not pull it up.
The average cost for a Engine Coolant Temperature Sensor Replacement is between $118 and $168. Labor costs are estimated between $88 and $113 while parts are priced between $30 and $55.Get a personalized estimate based on your location and specific car. Estimate does not include taxes and fees.
Parts & Labor BreakdownLabor: $88 – $113Parts: $30 – $55Estimate does not include taxes and fees.Best PracticesWhen replacing the engine coolant temperature sensor, always use a factory part, clean all the connections, and ensure that the entire cooling system is in good working order with fresh, clean coolant.
Common SymptomsWhen the engine coolant temperature sensor is defective, the vehicle may be hard to start and/or get poor fuel economy. Also, a defective coolant sensor will not signal the power train control module (PCM) to operate the cooling fans, which may cause the vehicle to overheat.
The Check Engine Light may illuminate with a fault code set for the engine coolant temperature sensor.
Common MisdiagnosesAn engine coolant temperature sensor code is not always caused by a defective sensor. It can be triggered by a defective thermostat, defective wiring, rusty coolant, or by a plugged or restricted radiator.
Log in to reply.