Transmission fault code assistance

I just purchased a 2006 Freightliner Sprinter LWB from the original owner with 152,000 miles. He has impeccable maintenance records. All were done by Freightliner.

Transmission fluid and filter changed at 50,000 miles
regular oil and filter changes.
air filter changes when indicated by gauge on box (rarely)
turbo resonator changes like 4 times!!!

The Sprinter has been largely unused for the last 2 years and stored in his yard. It was very clean, a little musty. Prior to that he used it for work as a mobile service technician and travelled a lot of highway miles.

I drove it home about 70 miles. Then drove it the next day to work. On the way home it went into what I assume was LHM. I was locked in 2nd gear and my OBDII code reader showed P0715 Input/Turbine Speed Sensor "A" circuit.

I checked the electrical connections to the transmission and found that fluid leaked out when I removed the multi prong plug.

I found some very helpful information on here including Doctor A's over 80,000 mile service recommendation. I also talked with a very helpful man, John at sprintertransmissions.net who recommended replacing the conductor plate, fluid, filter, gasket, and plug adaptor.

Today I purchased Trans fluid, filter, gasket, x2 plug adaptors, conductor plate, and service dip stick.

I decided to only replace the adaptor plug at this time. I wanted to eliminate one item at a time to better understand what the problem is.

I removed the negative battery cable. I cleaned the outside of the trans with brake cleaner. I removed the adaptor plug (& noted that the translucent o rings had flat sides). I replaced the new plug adaptor. I then cleaned the way back, inside of the plug adaptor of residual oil with motor/contact cleaner as well as the plug. I dried them both with canned air and connected them.

I reconnected the negative battery cable and went on a 10 minute test drive. No problems. No codes. Can it be that everything is cleared up? I do not understand how these beasts operate with relation to the computer and codes.

Is the code stored deep in the memory?

Should I drive it to Mercedes and have them check the codes?

Did removing the negative battery cable reset everything and it may come back?

Did the oil in the plug & adaptor cause voltage inconsistencies that set the P0715 code?

Thanks for any help in advance.

I've heard of memory being erased by negative cable removal for 1/2 hour, and if the code is gone for now it has been fixed by your service, but may come back in the future if it is another cause. It does sound like LHM.
I would check the Transmission Control Module under the seat for oily connections as well, as that can cause tranny signal anomolies

Thanks. I opened the transmission connector plug (back end cover). I did not see any oil inside or on the wires.

Anyone else?

Stuck in 2nd gear typically indicates that the speed sensors on top of the valve body in the transmission need to be cleaned. I think Doktor A's thread you referenced gives details on that.

boardhauler said:

I just purchased a 2006 Freightliner Sprinter LWB from the original owner with 152,000 miles. He has impeccable maintenance records. All were done by Freightliner.

air filter changes when indicated by gauge on box (rarely)
turbo resonator changes like 4 times!!!

Click to expand...

Regarding the air filter gauge - that has been a running joke since 2002 as few have ever seen it work and there was speculation as to how much vacumn is required to make the gauge move. Check your air filter.

Regarding the turbo resonators - if it hasn't been converted to the billet aluminum version, that may be the problem yet again: http://europarts-sd.com/turboresonatoreliminator-2004-2006.asp

Install a Dorman resonator, available on amazon for ~$30 and that will solve the resonator issue.

hkpierce said:

Regarding the air filter gauge - that has been a running joke since 2002 as few have ever seen it work and there was speculation as to how much vacumn is required to make the gauge move. Check your air filter.

...

Click to expand...

I'm not so certain that it doesn't work. When I tried washing my OEM filter and then installed it before it was completely dry the filter minder went to red. that is the only time I've seen red (on the filter minder) during 7+ years of operation.

60,000 miles/3 years is what I recall MB recommends. I monitored my filter minder, but gave up before I saw red. That was at about 5 years and 80,000 miles service if I recall correctly. My filter didn't look bad. Highway miles, very little on dirt roads. The downstream side/MAF sensor body was still white paper towel clean. I could still feel air flow through the media when I used a not up close air gun to blow the dirt out counter-flow. (I know. Not very scientific.)

So maybe the Filter Minder isn't a joke, but I can't say for certain. I chickened out before it showed any restriction.

I've read a few threads where the air filter is incorrectly installed which allows dirt to by-pass. I find that correctly installing the filter on my OM647 needs to be done carefully. I prefer to not disturb the filter any more than necessary, but that's just me. The recommended 60K/3 years should be fine for most drivers.

vic

I drive a lot of dirt roads and I have never seen my air filter restriction gauge move.

I drove 30 or so miles today. I did not notice any problems except a light RSN at 1500 rpms. I did not ready any code on my OBDII. No MIL.

It seems that cleaning the plug and replacing the trans plug adaptor has fixed the problem and the ECM has reset itself.

Dropping the pan and replacing the gasket/filter and cleaning the speed sensors is on the list, just hoping to wait until the weekend.

What do you guys think?