I've got a "Service" message with codes 21 / 23 on my Allison MD3060 display which I know means that the TPS failed high. I believe this happened when I was adjusting the valves and to get the valve cover off the engine I had to move the bracket that the TPS is bolted to. I didn't remove the TPS from the bracket, just pivoted the bracket out of the way. In reading the Allison service manual it says to reset the throttle calibration, use a Pro-Link tester or cycle the ignition 5 times. Since I don't have the tester I tried the ignition cycling process but it didn't clear the message or the codes.

Any suggestions on what I'm doing wrong?

Thanks,

Steve
96 American Tradition
Spartan Chassis, Cummins C8.3L

Codes 21 / 23 is for Throttle Position Sensor.
Check
1. TPS connector is properly connected.
2. End of TPS cable is pulled out properly.
3. Engine fuel lever I in idle position.
4. Engine fuel lever provides proper amount of stroke on TPS cable.
5. Wiring harness to TPS has no opens, shorts-between-wires, or short-to-ground.
6. TP for proper operation and resistance readings.

samert111...
Welcome to iRV2! I know this is your first post so it is perfect for me to point out to you how helpful our members are here at iRV2!
(Great Job Rex!!)
I hope you decide to participate more on the forum...along with joining the Fleetwood Forum (just say Karma please" and it will be done!)

Again...Welcome to iRV2...please visit and post often!!


MM

Thanks Rex,
I've confirmed items 1 thru 4 on your list and I'll look into the other 2 tomorrow after I've spoken with the Allison Tech line first and update on what I find out.

This message has been edited. Last edited by: samert111,

I've been working on a couple other issues and now have it all back together and went for a test drive today.

The “Service” message on the Allison display went off after about 3-4 miles but the shifting was not normal. At first it seemed to be up shifting normally but would not go into 6th gear no matter what until I put in the economy mode then it seemed fine for a bit then it would not downshift at WOT at first, then it would, then wouldn’t again. On the return trip home it started up shifting really early (not in economy mode) like at 1500 RPM no matter how much pedal I was giving it.

The code 21-23 is still in memory and will stay there until cleared by the diagnostic tool Allison uses according them.

So I guess I need to take it in and see what they find.

Thanks for the feedback.

Steve

Just wanted to update on this.

Today I took it into the local Allison service center and they found the TPS to be bad. It was replaced and it is now operating normally. It must have just been a coincidence that it happened after I adjusted the valves.

Steve,

Just curious here. How many miles are on your C8.3? How difficult was it to adjust the valves re: turning engine over to TDC on each cyl. etc? My manual doesn't show the procedure (I think...but will check tonight or tomorrow). Do you have a link to one or a PDF of the manual?

We are the 3rd owners of our rig and I do not have complete service records (minimal would be a better description...) and am doing service to it as I can.

FWIW, I have changed out the U-joints, leveling valves, shocks and serviced the Generac generator with new oil, fuel, oil and air filters and new battery cables. I still need to change the drive belt (assuming I can figure how to get to it) and possibly adjust the valves on it. I also still have to change the engine oil and filter again and have yet to change the trans. fluid/filters and coolant/filter, as well as the air filter.

Any and all comments are appreciated.

Ken

quote:

Originally posted by quikduk:
Steve,

Just curious here. How many miles are on your C8.3? How difficult was it to adjust the valves re: turning engine over to TDC on each cyl. etc? My manual doesn't show the procedure (I think...but will check tonight or tomorrow). Do you have a link to one or a PDF of the manual?

Ken

Ken,
Sorry for just getting around to answering you.

I have 90K on the engine. The valve adjustment proceedure is not hard at all but you need the barring tool to rotate the engine. Mine was a real PITA becuase I had very little stroke on the ratchet driving the barring tool because the frame rail was in the way. I tried to use my 3/8 air ratchet but it wouldn't budge it.

The proceedure was in my little green Cummins engine book so I don't have a link to it. I can photocopy it and send it to you if you send me an email at samert111@yahoo.com.

There is an engine timing pin under the fuel pump for finding TDC for #1 cyl but on my setup the air compressor is just below the fuel pump and I can't even get my fingers on the timing pin so I had the wife watch #1 cyl valves and when the intake closed I rotated the engine a bit more and figured its close enough to TDC.

Then you can adjust the following valves.

#1-I&E, #2-I, #3-E, #4-I, #5-E

Then mark the balancer and rotate engine 360 degrees and adjust the following valves?

#2-E, #3-I, #4-E, #5-I, #6-I&E.

Clearance is Intake-0.012" and Exhaust 0.024".

According to my manual this is suppose to be done every 24K miles.

Funny thing is that mine didn't need adjusting after all this.

Good luck.