Error Codes P0720 in conjunction with P0500 2001 S430
 

Been everywhere, seen everything but nothing that can help me with this issue, so I'm reaching out to YOU the experts. Here's my story and I'm sticking to it! Bought 01 MB S-430 with 131k on her. Got er cheap, because of error codes. Bought lots of older Benz's usually I stick with E320's, but such a great deal, I couldn't resist. Seller was honest about Error codes P0720 and P0500.

I get to the sellers house, car is covered in an inch worth of dirt and dust, he's putting in a brand new battery. Brought my cheap innova OBDII scanner. Asked if I could take it for a spin and couldn't even see the road because of all the dirt on the car. So he hooked up the battery (must have been sitting there for at least several months) and I take her out. She starts right up, drives fine, short hop and everything appears fine. He said, call a tow truck driver because I live about 20 miles from his house. He was cool, upfront and honest. The guy had money so I think he (like he said) just wanted it out of the driveway. He had enough cars, said he didn't want to spend anymore $$$ at the stealership.

So I asked if we could at least wash it down with water so I can drive it home and I have AAA so I'll call em if I get stuck. He just brought me a wet rag...haha... So I clear off the windows enough to get me to a gas station. Get her home NO PROBLEMS NO CEL! I think I've just got the deal of the century...So I live in Riverside County Ca, drove my grandson to his friends house in San Pedro 200 mile round trip... NO ISSUES! a day or so later, I let the wife try her out. She 4'11" so she puts the seat all the way up and adjusts everything and BAM! Cluster lights up like a X-mas Tree! Speedometer goes completely to zero while engine/trans (722.6) goes into limp mode... I'm like, WTF did ya do? She's got that look on her face like OMG, I'm jinxed and I confirm she is!

I have some experience on E320's W210 but not on S-430 W220. And I know the issues with these transmissions. So I get out my pos OBDII and sure enough, just as the guy said, error codes P0720 and P0500. Put the car up on the jacks, sure enough the 13 pin connector on trans pours out old trans fluid. Order connector with o-rings, filter and gasket. While waiting for parts, I noticed trans fluid traveled to the TCU (TCM) and was filled with tranny fluid. Now I have heard about this but NEVER seen it for myself.. All I can say is WOW! SOAKED IN IT. Opened TCM and sprayed contact cleaner and all contacts to TCM... What a mess! So I get new parts in and noticed transmission was NEVER serviced as the fluid was dark brown and the filler tube cap still had the tab on it that's put there from the factory! The old owner got car from his parents who must have took the "sealed for life" Trans literally... So here I am thinking, YOU GENIUS YOU, you found the problem and she's gonna be just fine.....NOPE! Nothing could be further from the truth.

So I start her up drive her less than a quarter of a mile, same thing. Speedometer goes out, ABS, ESP, Airmatic, ya know the whole list and limp mode. Shut her off turn it back on and again, after a few miles same thing. Checked out speed sensors on every wheel for shorts or bad sensors, nothing to the naked eye. All look good, but replaced one for the heck of it. Took car to transmission shop, guy clears out Tranny code but comes on again. So he takes it for a ride while scanning live and says all sensors showing problems (I assume that's what the P0500 code means). He says he things it's the ABS/BAS module... But he adds, "you like to do your homework, so try to see if you can find something or a fix"... lol... He's the friggin expert and I'm suppose to figure it out? lmao... When car is running, it shifts smooth, it runs excellent. I have cleared out the whole passenger side SAM box and cleaned everything to like new condition....

Is it the ABS/BAS module, TCM, or the tarns conductor plate? These two codes (P0720 and P0500) seem to go hand in hand. Is there a reading on each wheel Speed sensor I can take with my OHM meter to see if they are good or bad? What am I not seeing? The P0720 is a trans error code and I am sure can only be deleted with the appropriate scan tool but the P0500 can be cleared with a OBDII right? ... Since I have 2-97 e320's, 1-06 E350, 1-2000 E320 and now 1-01 S-430 any suggestions on a good scan tool that won't break the bank? I know, you're thinking this guy (me) has lots of cash... NO WAY... I buy these cars cheap. Usually from people who feel just like I do right now....lol... Fix em up, sell em or like this 430, keep em...I get too attached to each and everyone. Like you, I LOVE MB! There's nothing like them... And I've owned everything! Well, just about...

Looking forward to hearing from you all regarding this matter, and THANK YOU in advance for any supportyou may have...:music:

Thank you Biff for your summer opus----I most liked where you say you purchased the car dirt cheap for the wife, only to find out that you may need a new transmission conductor plate.

Your first mistake,besides purchasing the car, was believing that you, your wife or your dead beat mechanic could read transmission codes with a cheap OBD reader--you can't.

Your second mistake caused by your ignorance of MB fault codes has resulted in believing the fault lies in wheel speed sensors.

To get back into your wife's good graces you need to find someone who can read the MB transmission faults---once that is done you will know exactly what is wrong with the transmission all else will be like three dogs running in a circle chasing each others tail!!

WOW Plutoe, guess after the novel I wrote, you didn't read it correctly. Never said or even hinted I bought the car for the wife, where'd ya get that from? The dead beat mechanic you insulted didn't do the live scan while driving the car with an OBDII scanner...lol...Again, where'd ya get that? Even us newbies are well aware an OBDII scanner can't clear transmission codes. Didn't know the P0500 was a transmission code even though the P0720 is... 31 years with the same woman and I need to get in her good graces?

Ya know brother, I was looking for help from someone with an inkling of what the problem may be, if I wanted sarcasm, I would have asked a Yugo mechanic. lol... My ignorance led me to a problem with an OBDII scanner, it told me basic information. That I had a P0500 issue in conjunction with a P0720 error. The dead beat mechanic gave me more specific information such as the VSS were all showing bad, even he knew it wasn't the Speed Sensors. I hope it made you feel better, trying to make fun of someone (incorrectly at that) instead of supplying us with much needed knowledge I was hoping you had... I will check out the conductor plate. I have done that replacement several times, so maybe even a dummy like me can do some good...Thanks for trying to help,,, I think...

Now I know what they mean by "read and read again"...haha..

My 04 S430 went into limp mode at 65k miles. I bought it just under 60k miles so I knew exactly how you are feeling right now. Thank you for the humorous novel by the way.
At the time, I wasn't smart enough on these OBD codes so I just bought it to the dealer. The turbine speed sensor VGS went bad and the part was ~$850 and SDS programming labor was ~$450. The whole transmission valve body had to be replaced.
The next 35k miles had been problems free for me. I think you will enjoy the S much more than the E after you get over this humph.
Info on code P0720: http://www.obd-codes.com/p0720
Good luck

DrDoe, THANK YOU for the hope! Also, for your experience with this problem. Sometimes, we just need a lil push, ya know a positive gesture. I to think the S-Class is a much nicer ride than the E's. That's why I want to fix er up and keep her. I will probably replace the conductor plate in the transmission as I have done this a few times on the same transmission on the E-320's. I'm getting pretty good at it...lol... Just hoping that's what it is. I've also decided to get an icarsoft MB II scanner, as I drive only MB's I'm sure it will come in handy again and again... At least I will try to reset the Trans code (P0720) before I replace the conductor plate. I like to flip these cars as I have a 16 year old Autistic daughter who needs all the extra $$$ I have. She's the reason I do this...

So, $1300 later your car runs great? I'd say that's not a bad deal at all...Thanks again for your understanding and help...

Yes. Transmission was the only major issue I had with my 04 S430.
I got the Launch Creader CRP123 for $145 shipped couple months ago and it can do AT/SRS.
I think it's hard to flip the S as people are generally scared of the repair bills. It's really true that there is no cheap S class.

You may be right my good friend, but out here in So. Cal, they are a much wanted car. Ones with higher milage than mine are going for about 5-6k... And what ya get for that? Well...forget about it...haha Nothing compares...

Okay, so here's an update, remember in my novel I said the trans fluid managed to crawl up to the TCM and it was soaked with tranny fluid? Literally took hours to drain the fluid out and then take apart (no easy task) to pull the circuit board out. Then I had to spray the board with contact cleaner...

Well I decided to take another look at the TCM circuit board and sure enough two small resistors (or something) were totally destroyed. I'd bet the farm these are what's causing the error codes P0720 and P0500. The somehow are in conjunction with one another. At least that's my guess... Hope to send pics but it's so small, Good news? Do not have to replace the trans conductor plate. Bad news, I hear the TCM is friggin expensive... And after all that, it doesn't mean it will fix it, but I'm pretty darn sure it will...

Thank you for the confidence brother. You were right, I was feeling totally lost and frustrated.. Persistence does pay. I'll let ya all know how it comes out...PEACE!

The pen and the pencil show the defective resistors that are no longer there. And yes, you could see that they once were! I sure hope this helps others in the future...

https://cimg0.ibsrv.net/gimg/www.mbw...c572eedde8.jpg

Nice findings. Congrats

There are guys who will fix and resolder those components.

No need to replace the whole board

I was able to pull a computer mother board apart and soldered two similar resistors, but have to get codes cleared out to see if it works. But as of right now, same problem. Tusabes, can you recommend someone if this doesn't work?

Update.... Found one more missing resistor. Replaced and put TCM back in car and the P0500 and P0720 errors disappeared. BUT new pending error code P0715 which is good! Believe it or not, this code is easily cleared with the proper scan tool! Car is in Permanent limp mode until this code is cleared out... Which will be at Noon today... Keeping fingers crossed... If it remains in limp mode, at least I know it's because of the TCM not the conductor plate! WARNING!!!! If your TCM was soaked in tranny fluid, then chances are it needs to be replaced... It destroys the resistors, but taking it apart to clean it, may cause it also... So at this point, it may have been me who caused the 3 missing resistors or it beinf soaked in tranny fluid for so long. Either way, why take the risk?

How much sleep did you get between all of these works? I don't think I could manage the soldering.
I ran into this technical document on 722.6 that worth saving: http://www.all-trans.by/assets/site/...es/722.6.1.pdf

LOL.... I'm a musician, so I'm use to working with lil or no sleep! THANKS for the article, and yes, you must have extreme patience when dealing with these very small soldering points, that and a good magnifying tool. 3 so far, when will it end? haha

Seems TCM is the problem even after my attempt at soldering micro resistors....lol.. I gave up and decided to order me a used TCM. If this doesn't fix the problem then a new conductor plate will.

Page 22-23 talk about TCM testing. Did any anything failed?

I'll read those pages and let ya know. I ordered a used TCM and a icarsoft MBII scanner. Tired of relying on others to do error code resets figured since I have so many MB's this will come in handy. If for whatever reason I have codes after I reset them, then I know I have to clean up the current conductor plate or order a new one. Either way I'll keep you all posted

Sounds like you are heading in the right direction. I love the story about your wife driving your car... I told it to my wife.... that means stay out..lolol I just bought a used TCM/TCU today and a icarsoft MBii yesterday. When you read the transmission codes they come 64/65/152 something like that basically saying your TCU/TCM is defective.

I plugged in the new chip hours ago and cleared the codes with my MBii and was on my way.

I got the chip for $150... the stealership wanted over $2200 for the repair that takes all of 5mins including the scanning ...lol

Earl Mignott, so cool to read your reply because it's exactly what I just did... Okay, I got the new TCU/TCM yesterday. One of my concerns was when I put it in, would I still have error codes? Well, I did. I assume these codes are reported to and stay in the ECM until they are cleared out. I got the TCM for exactly $150 (just like you), and awaiting the icarsoft MBII i980 scanner I bought for $158.00 off of ebay. The limp mode went away, but the old errors P0720 and P0500 are still there always showing pending.

I assume until I get the scanner to clear them, I will get these errors. Reader/scanner should arrive today or tomorrow. One thing I'm a lil puzzled over with this scanner is that it will NOT work with my w210's? Seems it will work with my 06 E350 and my 01 S-430, but not my 00 or 97 E320's. BUMMER! Something to do with the 38 pin in the engine bay of the w210's?

THAT SUCKS! lol... Because (icarsoft) state it will work with all Benz from 1996 on. I have seen 38 pin connector adapters that have an OBDII style connector at the other end, do you think that will work? I hope so. This scanner seems like it will do just about everything and give me stock tips.

I felt so bad after my wife drove the S-430 for the first time, because that's when everything went haywire...lol Poor thing may never test drive my cars again! She's jinxed and wishes bad crap on me. lmao...But who's there to hand me a wrench when I'm underneath my cars? That's right... Now that's a wife. We yell at each other, call each other names I've never thought possible out of our mouths, but in the end, it's a high five and hugs as if we killed the devil together..

She's always saying, we should do a "DIY, Love-Hate, MB YouTube videos" I can imagine all the feminists with torches in their hands standing outside of my home, waiting for me to leave the house! hahaha NO THANKS! I'll keep ya posted after I clear the codes. As I said, if they come back, the it's either the Conductor plate or the ABS/BAS module. With this scanner I should know more, can't wait to get it! PEACE and Thanks!

After plugging in the chip you have to clear the transmission codes, yes you are correct. make sure you get the MBii not the small i980... the i980 didn't work for me... I played with it for 2 days... MBii worked right out the box.

Thank God you got it out of limp mode...

Good luck

Yeah, that was a sigh of relief (no more limp mode). Can't wait for the scanner to arrive, and yes it is the bigger one with the 4" screen. Sounds perfect for my endeavors. I just found out it will do the 2000 E320 because beginning with that year they stopped using the 38 pin connector... Your reply gives me hope, you wouldn't believe how some have tried to discourage me and make me feel as I had no chance in hell...lol... If I'd of listened to them, I'd of hung myself by now...lmao... So onward we rock... Hey, we're not here because we hate our cars, just the opposite!

DrDoe, The information in this article is a MUST! Thank you, I've seen it before, but never read it as it pertains to my issues... VERY VALUABLE especially because you don't have to open the trans to see if your solenoids are working at the proper ohms! TOO COOL... THANK YOU, your help has been priceless...

UPDATE: Okay installed new (exact number match) TCM same issue P0720 and P0500. Got new MBII i980 Scanner from icarsoft (yeah) and am finding some issues YOU guys may be able to help me with. I cleared em out but they just keep coming back. I hope this scanner was worth it. Under transmission DTC's I get the following (one of 4 errors but they are all the same) The (right rear, left rear, the right front, the left front) wheel RPM signal transmitted by control unit N47-5 (ESP, SPS [PML] and BAS control unit) over the CAN bu is intermittently implausible

DTC: Short Circuit to Positive

This starts with numbers 118, then 119 120 and then 121 (remember I said four errors) These are all the same thing. I take it all the Speed Sensors are good so (if I'm reading this new scanner right) the Control Module N47-5 is the issue? I'm frustrated and pissed, something is shorting to or from this module? I have NO CLUE what-so-ever, but I have a feeling someone here does... PLEASE HELP ME! lol Have the wife and kids tied up and ready for heads to roll...haha... NO NOT REALLY, but hey, someones got to pay for my mistakes...lmao THANK YOU in advance you guys... Help a fellow MB owner fall in love again with these cars...

Code P0720 can't be reset according to the 722.6 document. It would clear by itself after the problem had been fixed.
My 1st guess would be the VSS if all wires checked out ok. N2/N3?