-
Trans/Engine issue leaving driveway
This morning, as I was SLOWLY leaving our driveway to take the coach to storage things went haywire. First, my check engine light came on, then it blew black smoke (which I didn’t see, but my spotter did), the engine revved, brakes didn’t seem to work, and coach bucked. I was going all of 3-4mph, and when the coach did stop (I may have shifted into N…it all happened so fast), the tach was reading nearly 2500rpm. I shut it down right away. Prior to pulling our of the driveway, it had idled for several minutes while disconnecting from power.
I checked the dash codes, and got the following: (1.) Engine, Boost Pressure Elec Fault, Active E(
Before the above codes showed up on the screen, I had the following on what I think was the Engine code screen: (line 1) Mid 128 SW ID, (line 2) 39.01
I called PASS, and he had me go to the Allison panel for codes, and there was one: D 2312 which he said didn’t give him any specific guidance. He asked if I had run through water, and I said, no, but it had rained like nuts a couple of days ago, but it’s been 90F and dry the last two days. He suggested that I start it up and try to move it (it was in the middle of street). I hung up with PASS and tried that. As I SLOWLY pulled back into our driveway, it was okay, at first, then it started to increase revs, again, I stopped, and shifted to N, and it was at about 2000rpm. I shut it down. I did not get a check engine light, but the 2312 Allison code came back (I had cleared the prior code). I haven’t called PASS back.
Recent history: About two weeks ago, the Allison TCM was replaced along with the retarder solenoid. The retarder was intermittently operating, and the trans had failed to go into gear from N to D on several occasions (I would get a flashing 6). I’ve driven 1,000-1250 miles since the repair, and it has worked flawlessly. The only changes since it last drove on June 1 was replacing the Vanner EC70D on Saturday to address a Hi/Lo Battery light and flipping the “Amber turn signal” switch in the engine compartment to “Red turn signal” for my tow car because the brake lights weren’t operating on the initial setting.
I appreciate any input as I’m, literally, at my wits end.
-
7 Replies
-
Why does it never occur to me to search the web? Looks like Allison fault code 2312 points to connection issues between the control pad/TCU and/or ground issues. At least that narrows it down…not sure why PASS didn’t have those details.
I still had the check engine light, though, and I wouldn’t imagine that was triggered by this…
-
Hope you find and resolve the issue SOON.
Perhaps a call to the person who did the recent Allison work could help you determine where to first check connections.
Please let us know what you find! Best wishes!
-
Circling back with an update on this for posterity. After multiple discussions with a DD/Allison shop, a seated coach company that runs 35 Prevosts, two Prevost reps, and a fellow owner who is VERY knowledgeable, we had a consensus on the most likely issue: throttle position sensor. Following the verbal investigation, a road tech came out, and, of course, the over-revving issue did not recur. Proactively, we replaced the throttle position sensor, and now we can rule that out going forward.
I continued to get boost pressure error codes (as I have since buying the coach), and, yesterday, the gauge was pegged at 30…even at idle. Of course, that also did not recur upon the tech’s test drive, this morning. After further investigation and digging, things are pointing to a wiring harness associated with the boost sensor. I had mentioned that, yesterday, as a possible cause as I recall seeing posts about this harness issue, previously. That is now on its way from Syracuse, and I’m hoping that puts this issue to bed as my wallet needs a major nap!!!!
-
Robert I have seen turbo boost sensor go bad ,mine lost all boost. Sensor is located right on air manifold as you open door for engine bats .as I recall not to pricey 150 bucks. Good luck. Was on Detroit series 60.
-
I had to have the harness done on my 02 Marathon, here’s the link:
-
To (hopefully) provide the final chapter to this issue, the wiring harness was replaced for the turbo boost sensor, and all is well, thus far. Considering that I’ve, literally, been throwing turbo boost error codes since I pulled out of Olympia, last July, I think it’s about time I put this behind me. The tech said that the harness was testing fine until he started moving it around while testing…then the readings started to go haywire.
The throttle position sensor definitely seems to have resolved my over-revving issue, so that’s good. Here’s hoping that we’ll soon be able to start doing things we WANT to do instead of things we HAVE to do…
-
Hi Robert,
So glad to hear that you have (hopefully) overcome all of the electrical and turbo issues! You are fortunate in that you have the mechanical aptitude and background to identify, much less handle, most things with your Coach.
We’re headed back to Olympia by July 5th to finish out some IOU items and do a couple more upgrades (interior LED light pucks throughout and possible Kote paint the roof, etc.)…before finally starting the trek out to Indio!
Wishing you many wondrous adventures and safe travels!
Log in to reply.