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CEL/SEL
About 3 hours into our drive to oyster fest got a CEL.
I learned the hard way about CELs. Got the first one ever last year and took coach to Interstate shop where they hooked laptop into diagnostic plug and all hell broke loose with loss of speedo and tach. Al Hermans to the rescue with explanation and reassurance and the DD guy who spoke at last year’s maintenance seminar at ETLC confirmed that is a known problem that tends to correct itself with time but that most shops don’t know about it or how to avoid it. Short story is that I have learned to largely ignore those CELs and/or investigate with flash codes and stay from folks with laptops and no Series 60 experience and no interest in calling DD reps that do.
What was different this time is that as I continued to tool along with CEL on, got SEL that was only on briefly. Stopped and did the flash codes and got 34 and 46 on the CEL and 64 on the SEL. After restarting bus no SEL or CEL on, so looked everything over and went on our way. No performance issues at all. Happened again later on with only a brief on and off of the SEL and both the SEL and CEL cleared with restart.
On the way back happened three different times. No rhyme or pattern. Totally random and no performance issues or visual concerns looking at motor/turbo. A couple of times when I stopped quickly and checked codes the SEL threw 25 – which is, of course, no active codes. In addition, CEL also threw 54 at one stop.
34 is turbo boost input voltage low. 46 is ECM battery voltage low. 54 is vehicle speed sensor fault. 64 is turbo speed sensor input fault.
None of this makes any sense to me. A couple of times the analog turbo needle stopped working.
I am reluctant to have local shop hook into the diagnostic plug because of past issues and doubt that would give any more info than the flash codes. Of course, their main business is trucks and they have little interest in older buses with Series 60 DD.
So my question is where to go and what to do? The DD has had the turbo recall fix. Have followed problems on the community about the turbo harness. Just change that out? DD has 72000 miles on it. Thanks. Sorry for the long post. Mike
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7 Replies
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Mike, my first reaction when I read the post was a poor ground or some intermittent electrical connection. Before I went to DD to find out what is going on I would unplug and plug the connectors at the ECM a few times just in case there is some corrosion. There are contact cleaners available that likely should be sprayed on the terminals also.
I would look to see if there is anything obvious that might be a chafed or pinched wire bundle.
If that has not affect then I would set something up with a DD dealer, but make sure the dealer is aware of the issue and can correct the problem you had previously.
Keep in mind there are only 3 things that will cause an SEL and they are easy to check at the sensors. Low coolant level, high coolant temp, and low oil pressure. It sounds to me that yours is system related and not exclusive to a sensor.
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I had the same problem and it seems I fixed it this weekend. I bought a new wire harness for the turbo boost sensor. took 2 hours to install. Soldering the wire to the lead from the ECM took the most time. Cramped spot to crawl into. Ran the coach for 50 miles. No CEL. No turbo drop out either. I tested the ground wire with a meter and it was dead. Wiggled back and forth and would get a reading. I have to surmise this was the issue. I spent thousands trying to fix this at a shop.
Cal
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We don’t have statistics, but from various posts over the years a whole lot of problems seem to relate to poor grounds.
Many moons ago I had an inverter acting up and when I disconnected all the ground terminals at the chassis ground on the frame behind the chassis batteries I saw a lot of white corrosion. I cleaned all the terminals and got rid of the corrosion and the inverter issue went away and never returned.
Sometimes we get lucky like I did by starting there to isolate the problem, but like air leaks, we have multiple places for bad grounds and it is very time consuming to chase them all.
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Congrats, Cal. After reading all the posts and talking with Rick Armes at Volvo and with Cal, I decided that this baro sensor and harness is the weak link and when it goes weird things happen so when ahead and replaced mine this weekend too. Waiting for next trip to see what happens. Total cost just under $200 and a backache. Connected the cut pink wire with Suzuki motorcycle connectors. Mike
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Good job Cal! I have been having the same issues for a quite awhile. I had the bus at Clark Power in Knoxville in December 2018 and they showed a ‘Throttle sensor – input voltage low’ fault logged 255 times. Unfortunately, it was not in fault mode at the time and based on my discussion with them I did not hang around there for two or three days while they worked me in. I think I will replace the harness this fall and hope this does the trick.
Mike, please let us know if your issues were corrected by replacing the harness.
Cal, we were parked next to you in Spearfish last summer for several days. Hope you and your wife are well.
Jim Watkins
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Jim, great to hear from you. I replaced the harness and drove 500 miles this weekend and not a CEL or SEL. That was a tremendous relief. I found that the one connector on the harness had a break inside the molded connector. the ground wire was ok when I tested outside the injection molded connector. It was interment and when the harness expanded when it got hot it may have spread the molded plastic enough to cause the issues.
Jim, Are you still full timing?
Cal
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Did 500 miles this past weekend. First trip since replacing the baro sensor and harness. No lights. Hooray. Mike
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