Having a problem erasing codes on a 528i with 5l40e automatic. Everything works on the trans not in limp mode on this model that is a gear icon not the message. Shifts with paddles in both auto and manual mode. No slipping.
I have five trans codes P0-705 twice and 743 53 and 63.
Some background on the diag so far.... Read with standard reader centech from hb. Noticed that to get trans code you have to rescan don't know why was not in instruction book. Don't know what it puts out on the can bus that says just give mil codes and when I ask again give me trans codes? Anyhow because I recorded the codes and the trans was working fine I selected erase to turn off the ses to see if it would reoccur. It said done erasing but checking ses did not get shut off reread and same codes.
Ok get the big stuff out. Tried with a more sophiscticated reader more codes but they were associated with my abs which ic on another thread so I wont go there I wrote it up and posted a bunch of info with bluebee several years ago. MY take on this unit is pump your brakes if you don't know when it will fail and its that flaky what's the point. Anyhow I have 4 bimners 94 and older with abs that has never failed but like my 99 disco as soon as they added out of control logic no abs is safe.
So I put an autologic on and the first one could not read anything so I went over to a friend and he put his autologic on and supposedly erased the codes drove off and did not notice the'
limp node icon illuminated.
Well read somewhere that if you erase the codes it will put the trans in limp mode. Ok don't know if that is true but it did happen. OK reread the codes and presto out of limp mode same
codes. Not sure what the first autologic did but it did go into limp mode
Any ideas? Connected and disconnected the only connector to the trans to see if it was loose or dirty no luck. This model trans has the internal mode switch and all sensors come thru single harness.
Of course I will tear the trans apart if necessary but its working fine.
Thanks for any help have only asked two questions on this forum but read often. I only post questions to this forum actually.
Well opened up to the computer area with ecu and tcm/ags wiggled the wires around and now the scan tool reads the codes first time. also now have a p1189. Looks like wiring issues
let me clarify the comment from above --- in a single read with the scan tool I now had 6 codes the extra one (not the orginal 5 trans codes) is the p1189. Only read the bus one time no rescan required. Why would the ecu send all 6 codes when a single p1xxx code is present and not if only the 5 trans codes are there. There must be some additional protocol occurring between the tools and the ecu
when we used the autologic the ecu apparently does not like the "erase protocol" being requested by the autel/centech scan tool. the autel/centech scan tool has no error handling is mt guess so it just says done and nothing happens.
The autologic puts the trans in limp mode after erase and turns on dash gear icon. If I reread the codes with the autologic it comes out of limp mode but leaves the codes,
Well the bmw head tech suggests to reprogram the tcm. may use the inpa to do this and see first if I can read from the tcm. If it cant be read it maybe wires or unit.
So it appears transmission codes are stored in the ecm and detected in the gs20? Does the gs 20 store codes or just retest at each startup and forward codes to the ecm. Is this also what the abs unit does and if they both work together on joint tasks who coordinates the work. The ecm? Does anyone have a block diagram with these three units. I assume each unit reports information to other units either as a request or when things change on devices they are responsible for ...
Well at least I have a way to buy pass testing the wheel sensors given what has to happen for other units that use wheel sensor information. Looka like another failed abs control unit.
This maybe causing the transmission problems.
INPA can connect to Transmission. I didn't understand your issue. Is transmission in limp mode? Get codes over INPA. Why are you trying to hack ecm and tcm?
By connect, I mean you can read, clear and take action.
Well it went into limp mode when we erased codes with a Autologic attached to 20 pin under hood which seemed strange not saying the person who did it knew what was going on only that's what happened. Any reason that should happen? I don't know any reason so now I am interested. Next I bring it up to parts store and read it from the obd port and it comes out of limp mode. Now this is the year vehicle up to 9/00 that had both connectors. If you attach a simple reader to the obd port it reads trans codes in addition to the normal emissions codes.So I am reading trans codes from obd which may have been required to meet standards for that year but I have no control and no simple reader has control over erasing these codes. So I cant erase them don't know if they are really a problem just wonder why a simple reader would read them and then have no access to erase function guess this is by design.
So the codes that are readable even if invalid will not reset automatically or after three drive cycles. This would normally happen in this case it does not so what is blocking it. That's where I am at...
The trans works great has not changed since I owned the car in terms of operation the abs unit if still in manual mode ( I pump my brakes) with the trifecta lights and no limp mode light. Cruise works
odometer speedometer work. Those are from the same sensors the abs unit looks at so you see I am trying to look at the external items and figure out what is going on.
Don't know if the codes read are valid like how do you fabricate 15 codes? I am wondering where they are being read from and why would they be made available if they are not valid. I am assuming the computer that has the devices attached meaning the gs20 has the capability to disable the trans and it may simply report these errors to the ecu. Really trying to understand the paradigm of management of these modules. I may have to rewrite the gs20 but before that I would like to understand the whys. Should have either thru external monitoring or internal checks recognized the problem and corrected its state. Instead its in some kind of limbo and bmw wants to zap it and all is good. I understand that otherwise they would have a stack of cars. But these field problems are costly on both sides. BMW and me,
So instead of hacking I want to try to understand how the thing works first. I am hoping I will be able to say you are getting the codes because the persistent memory module in the ecu is set to retain codes until the hez code x64 is sent on the bus after the erase command and must follow within 6 seconds of the command or you need to repeat (prevent accidental erasing) well ok I made that up.
Sorry I am trying to guess my way thru this problem without disturbing the current state of the vehicle so that means learning something about how it ticks. If you had to guess what other information would you need to narrow the problem down without a diagnostic tool other than observation of the current system. It is hard for me and I am able to go out to the car. Cant imagine what it is like for someone on the forum.
If I can find the problem without a test tool it would be good but that probably wont happen I will have to look for the answers in the back of the book. LOL...
Its a great help thank you. I see that the ags uses a private bus line to talk to the dme but color wise it appears as the same bus. The can bus obviously terminates at the dme but I think you can jumper some pins in the diag connector to use them on the obd2 connector.
Using the title found some docs on e38.org called bus system troubleshooting will go from there. Looks like it is part of a larger document.
Anyhow thanks again will look this and troubleshooting over and see what I can figure out.
Hi, I did get a chance to read the gs20 unit however I can not clear or read error memory. I can do everything else to the gs20 module but I get a inh0009 error which most people blame on setting up the interface.
But obviously I can talk to all the other modules but the gs 20 tcm is not cooperating. However there are a bunch of pcodes that must be stored somewhere other than the tcm gs20 unit. These are read from the
obd2 port and not the 20 pin. I have looked at everything else with the 20 pin interface including the abs module which has front and rear passenger side sensor errors and the steering angle sensor. I know why I have the steering angle sensor because I replaced the module some years ago and did not set it up with dis. Anyhow I am guessing the abs module has the same broken internal wires as the first one did. Pictures are somewhere on bimmerfest under bluebees post.
So here are the pcodes that came out of the obd2 port (remember I was unable to read or clear error memory from inpa but everything else in inpa worked including testing pedals wires and solenoids on the trens and in general it works as it aluays has) p0720, p1747 48 49 50 and 51, p07 31 32 33 34, p1749 appered 3 times. p1749 is listed as a programming fault on the rom or the ram my guess is it is reading rom ok and is faulting on ram reads for fault codes which would explain the read error memory problems from inpa. Anyhow looks like this is the problem. Any other guesses. I also read the id and info thru inpa and it was ok.
well finally turned off the light but still do not know the cause. As mentioned it occurred during a battery jump from under the hood when the cables touched. The result was codes dumped into where ever they go and the inability to erase the codes or read with inpa the error memory or clear error memory any clear code operations thru the obd port would be successful but would come right back. Depending on the obd reader anything from no codes to about 15 trans codes. I replaced the tcm(gs20) and not codes and light turned off. I am still trying to figure out how during read and clear error memory the unit would return an error for that operation only error 19 had something to do with the interface. So if you get all the trans codes and trans works fine and you cannot clear the codes when reading and clearing error memory it maybe because the error memory which I assume is nvram in the tcm is faulty. Cannot find the specific chip on board. Easy to open the box and see the processor and ram and other chips including bus interface chip but not sure where the nvram is so I can determine how the current zapped only this chip which makes no sense. Unless error memory is directly accessible from the bus or some other circuit or it is actually located on another board and not on the tcm board. Will continue to check. Do not understand why some type of circuit protection is not on this memory regardless of where it is located.
all codes erased except code 97 steering angle sensor but like the tcm I replaced I cannot talk to this sas module so I ordered another. I will post the results for that item.
Did do some work for the abs unit. Sent the old unit out (this unit is on the bluebee post for abs) for repair to bba and they were not able to do anything with it so sent the current one to them and they repaired it and it works great found out I had to replace both wheel sensors
on the right side and funny the rear one worked right away which means no repair and correct reporting but abs before repair while the front wss did not work. So I put the old wss back on and it worked which means bba must have had to fix that connector because error before bba with same wss and no error after bba with old sensor. Not sure what is wrong with new sensor but it does not like it.
So now trying to recalibrate steering angle sensor and write id to it for changes abs unit. It has not worked in some time so Now I cant talk to the sas. Tried several different tools but my guess is it fried with the tcm. INPA and dis could not talk to module they did talk to everything else. I assume the other sensors lateral and rotational are ok befause no errors.
I am guessing they will not code until the sas is talking on the can bus.
bba was great to deal with and helped by great customer support kept me up to date and returned the repair in a timely manner. So great service great repair and good value.
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