Check Engine Light Problem

[barbar0ssa]

I believe I have a 2001 Thomas Saf-T-Liner MVP ER (EF?)



I have been working on my conversion for a year and am finally titled and insured. I took it to a mechanic to get an oil change, fuel filter change, and general inspection to see if it's ready to take on a trip.

When I started it, the check engine light came on. I was 6 miles from my mechanic so I let it idle for 10 minutes and then hit the road. I had a lot of distractions as it was my first time driving the bus, but it seems like the engine was limited. I couldn't get past 35 and about 1900RPMs. A mile out from the mechanics, the light switched off and the bus had more power and hit 45.

The mechanic gave it a clean bill of health, said he gave it a test drive and it was great, and he hadn't seen any limit or check engine light.

So later I was driving it away from the mechanics after hours and it did the same thing but the check engine light never went off and the RPMs never went above 1900-2000.

What is going on? Am I destroying my bus?

I just found the manual so hopefully I can get a fault code soon.

[Docsgsxr]

The MVP has 2 models. The ER (Engine in Rear) and the EF (Engine in the front).

I have an ER, when I start mine I have to let the motor come up to temp (about 190-195) for optimal power. If the motor is too cold, it will not "get up and go". My check engine light stays on until it is warm enough to run. I was told by my mechanic and my dad both that this was normal for these older motors.

If your light is on and won't idle high, I'd take it back to the mechanic and let him/her diagnose it, unless you think they caused it. Then find another one to go to.


If they changed fluids....... check the levels, could be that one of them is too low??

[Booyah45828]

If the light is on, a code should be stored. Have him read the codes and figure it out. It could be something as simple as a throttle sensor. But without codes it's anybody's guess.

[barbar0ssa]

Well, that answers another mystery! Good to know I have an EF.

When you say it won't "get up and go," do you think it is actually limited? If not, does it hurt the engine or the transmission to drive it when it doesn't want to go faster than 35?

[Docsgsxr]

I honestly don't know that answer, I usually wait until it is at normal operating temp before I drive mine. I do move it back and forth in the driveway as soon as I hear the drier hiss on the air system so i know I can get it to move....

[Booyah45828]

Barbarossa, yours will actually be limited. They call it engine derating in which it will cut off most power and rpm's will be limited to less then 2000. A whole host of engine codes will cause that. You can also cause that by having mismatched options entered into the computer.

[barbar0ssa]

Thanks for the info. Sounds like I'm stuck until I can read the codes.

[barbar0ssa]

I managed to use the engine diagnostic button to get the "stop engine" light to flash the error codes. It is flashing 235 235 115 115 and then repeating. According to this manual, 115 is the "oil change interval condition" which I can probably override somehow as I had the oil changed last Friday. Any ideas what the 235 code is?

[barbar0ssa]

Wait, is 235 the coolant level? I might have dodged a bullet.

[barbar0ssa]

Ok, now I can't make as much sense of it as I thought. Apparently 115 can also mean "Engine Magnetic Speed/Position Lost Both of Two Signals - Data erratic, intermittent or incorrect"

[Docsgsxr]

I think that might be what booyah was saying, throttle sensor, maybe??

[Booyah45828]

Both codes will cause a derate to happen. But only 115 should cause the 2000 rpm limit.

Code 235 is coolant level. Make sure it's topped up. If it is and the code is still active I'd replace the sensor. Check the wiring while you're at it but those sensors fail periodically.

Code 115 is more complex. It's essentially saying that the ecm isn't receiving the engine rpm signal from the crank sensor. Those aren't as common as the 235. Once again, check the wiring to and from the sensor, and if you're feeling lucky, you can replace that one as well. Otherwise you'll need someone with a scan tool and an oscilloscope to check it out.

[barbar0ssa]

Thanks everyone for your help. The speed sensor has been replaced, and now I just have code 235.

The problem is that this is a bad wiring harness and sensor for the coolant level. I am 2 weeks from my trip, my insurance is dropping me, and I've still never gotten the bus past 2,000 RPM! I am getting pretty demoralized.

So, 2 big problems.

1. Harness and sensor: I have a temp gauge, can I use an arduino to send the expected signal to pin 37 on the computer and just trick the damn thing into thinking that everything is ok? Maybe I could even tie into another wire that is sending an all clear signal and then both input pins would get the all clear. I don't even know what all clear looks like (hi, low, some pwm code?)

Getting this to someone and paying them the $400 to make this right is out of reach right now.

2. Insurance. I got turned down by 3 independent agents. The 4th put it through and got me insurance for about a month but now they are dropping me. 2 weeks, maybe I can come up with something.

[cadillackid]

Originally Posted by barbar0ssa

Thanks everyone for your help. The speed sensor has been replaced, and now I just have code 235.

The problem is that this is a bad wiring harness and sensor for the coolant level. I am 2 weeks from my trip, my insurance is dropping me, and I've still never gotten the bus past 2,000 RPM! I am getting pretty demoralized.

So, 2 big problems.

1. Harness and sensor: I have a temp gauge, can I use an arduino to send the expected signal to pin 37 on the computer and just trick the damn thing into thinking that everything is ok? Maybe I could even tie into another wire that is sending an all clear signal and then both input pins would get the all clear. I don't even know what all clear looks like (hi, low, some pwm code?)

Getting this to someone and paying them the $400 to make this right is out of reach right now.

2. Insurance. I got turned down by 3 independent agents. The 4th put it through and got me insurance for about a month but now they are dropping me. 2 weeks, maybe I can come up with something.

the PCM wont reset if you disconnect the main power from it?

a coolant level sensor is typically just a dry contact.. if the coolant temp sensor is off then you dont want ot just send an arbitrary signal to it as it affects how the engine operates..

its probably a 0-5 volt signal returbed to the computer from the sensor..

maybe the sensr is just bad? I replaced more than one over the years in older cadillacs I bought and worked on..

from everything I can read and talking to a friend that works with cummins alot, he indicates that the wires are not broken or shorted as its getting valid data.. but it just thinks the coolant is low.. youd likely get a 195 if you unplugged or shorted it..

if it were my Bus? this is a circuit I would rather fix and not just put a resistor on..

-Christopher

[cadillackid]

Originally Posted by barbar0ssa

Thanks everyone for your help. The speed sensor has been replaced, and now I just have code 235.

The problem is that this is a bad wiring harness and sensor for the coolant level. I am 2 weeks from my trip, my insurance is dropping me, and I've still never gotten the bus past 2,000 RPM! I am getting pretty demoralized.

So, 2 big problems.

1. Harness and sensor: I have a temp gauge, can I use an arduino to send the expected signal to pin 37 on the computer and just trick the damn thing into thinking that everything is ok? Maybe I could even tie into another wire that is sending an all clear signal and then both input pins would get the all clear. I don't even know what all clear looks like (hi, low, some pwm code?)

Getting this to someone and paying them the $400 to make this right is out of reach right now.

2. Insurance. I got turned down by 3 independent agents. The 4th put it through and got me insurance for about a month but now they are dropping me. 2 weeks, maybe I can come up with something.

who is it that is dropping you after a month? progressive? was it a commercial policy?

-Christopher

[Robin97396]

I also received a cancellation notice after one month with state farm. I've got one week left to find insurance. Contacted a number of local independent agents by email this morning and hoping for replies early next week.
Progressive told me they are not giving commercial policies for school buses of any kind. Seems to depend on who you talk to. I've gotten multiple answers in the same day saying opposing things from the same parent insurance company.

[cadillackid]

Originally Posted by Robin97396

I also received a cancellation notice after one month with state farm. I've got one week left to find insurance. Contacted a number of local independent agents by email this morning and hoping for replies early next week.
Progressive told me they are not giving commercial policies for school buses of any kind. Seems to depend on who you talk to. I've gotten multiple answers in the same day saying opposing things from the same parent insurance company.

interesting because progressive wrote me a Commercial policy.. we will see how long till I get cancelled.. I simply gave them the VIN and told them it is an 'S3800' international.. and she said 'the VIN verifies'.. and asked me how many seats it has. . I told her 14 positions but would likely go down to 10 or 12.. wrote it as a Commercial vehicle for personal use..

I supposed these reps write the policies and then once the bean counters investigate them then they are cancelling people?

state farm who I have 3 vehicles and a house insured just flat out said nope... my local agent gave me the number of a local specialty insurance agent, who I'll call if / when progressive drops me..

I cant go to national general or good sam as I dont want to have a bathroom in my bus..

-Christopher

[Robin97396]

I've read through the threads where people had success with insurance and got turned down every time with the same companies. The phrase that keeps being repeated is to visit your local independent insurance agent. Apparently someone needs to see that you're not using a school bus to haul dope or something. Different insurance agents have insinuated commercial use of a vehicle this large. No insurance companies seem to care if it has had modifications or not and simply don't seem any more interested in insuring buses as RVs.
I don't understand this. These are probably some of the safest vehicles on the road, with the exception of the heavily modified cute but scarey buses you see in photos now and then. My GVW is 24,090, which I thought would get me past a lot of obstacles.
As usual, I'm looking for a loophole. Their argument doesn't make sense for an insurance company to say it's not profitable to insure older buses. Insurance companies have not started regulating what vehicles we can use, by means of claiming its unprofitable? In a real world business model they charge more for higher risk. They know we're converting these and I think there is some kind of influence being made on all insurance companies to disallow buses, in any form. When it's basically a universal decision, who would you think was behind it? Do buses make us preppers or something?

[cadillackid]

Originally Posted by Robin97396

I've read through the threads where people had success with insurance and got turned down every time with the same companies. The phrase that keeps being repeated is to visit your local independent insurance agent. Apparently someone needs to see that you're not using a school bus to haul dope or something. Different insurance agents have insinuated commercial use of a vehicle this large. No insurance companies seem to care if it has had modifications or not and simply don't seem any more interested in insuring buses as RVs.
I don't understand this. These are probably some of the safest vehicles on the road, with the exception of the heavily modified cute but scarey buses you see in photos now and then. My GVW is 24,090, which I thought would get me past a lot of obstacles.
As usual, I'm looking for a loophole. Their argument doesn't make sense for an insurance company to say it's not profitable to insure older buses. Insurance companies have not started regulating what vehicles we can use, by means of claiming its unprofitable? In a real world business model they charge more for higher risk. They know we're converting these and I think there is some kind of influence being made on all insurance companies to disallow buses, in any form. When it's basically a universal decision, who would you think was behind it? Do buses make us preppers or something?

well i think the OLD way of school bus conversions often was busses that were well past the end of their life, a bunch of duct tape and rust .. thats not the way people are doing it now.. and the busses are designed to last longer and longer.. schools are running them less and less.. insurance rarely goes forward thinking...

now in OHIO any way my last bus was under 26k GVWR and had less than 16 seats.. I simply registered it as a passenger car andmy regular state farm insured me for it.. no hassles.. they looked at it like a club wagon...

this bus state farm wouldnt touch it .. my agent tried.. its over 26,000 lbs and is titled as an RV... I maybe should have not done it that way.. but then technically by driving it in ohio im in violation unless I renew my CDL if I Dont title and register as RV.. if I had a crash im guessing no operator's license means i go to jail.. so I best run it as RV and try to get it insured.. however I had a CDL before, so if I have to re-title it as a bus, go get a CDL and commercial insurance then so be it..

I THINK the insurance companies simply go look at how its titled and registered and thats what they go off of when they are cancelling people..

the VIN shows as a School bus and then the title shows RV.. they automatically think converted skoolie and bam! out goes the cancel letter.. my theory anyway...

I wrote my policy before the title got changed.. but my guess is at renewal time (if not before) I'll get the cancel letter...

I may just go and get my CDL back to be ready in case that happens.. as I know ill never have my bus in a position to be insured by any of the specialized RV insurance.. (ie bathroom)..

-Christopher

[Robin97396]

We better go back to Check Engine Light Problem. There's already a thread for ins.