getting 2 codes: U0073 and P260F

[banditxp]

so started yesterday well 2 days ago. Air bag lights came on. Turned off truck and back on and it never showed back up.

Today driving to the store (hot out 95*F and was like 90 the other day) and the air bag light came on again. Stopped at a red light and took off. Stuck in first gear and wrench light came on also. Turned into a parking lot and turned off and back on. Seems normal and went to the store. While driving to the store i floored it t 40mph to make sure its shifting right. It down shifted to 2nd and then back to 3rd and then back to second and shifted normal after that.

Driving back to stopped by auto zone and they pulled those two codes.
Drove to go get gas and about 1/2 mile from the gas station the Airbag, Wrench and engine light all came on. Pulled in and got gas. At thie point i was like on i have the base care warranty till 119K miles im going tot he dealer.

On my way to the dealer the wrench and airbag light came on again and now its stuck in 3rd gear limp mode. Dealer doesnt have techs this late int he day to check it out now and the codes they pulled were the same and when they looked them up its a communication error with the TCM.

So sense i could not drop it off tonight i am tomorrow morning and they will diagnose it for $49 and apply that to the work/deductible once they know if its under warranty or not. (the part) once they find what part. Im thinking the TCM or PCM.

Info: 2008 Ex, 81,000 miles. V8.

SO any ideas? i did not find those codes on here at all.

 

[Themightyquinn]

U0073 is CAN Communication Bus Fault-Receive Error. Source is the TCM. The TCM was not able to communicate with the network at one point in time and the fault is currently not present. The corrective action is to clear the DTC and repeat the network test with a scan tool. Also most U DTCs are the result of momentary communication bus interruptions. If no other codes are currently present, the module is not faulty. However P260F is not a malfunction code for the 2008 Explorer. Try going back to autozone and have them pull the codes again.

 

[banditxp]

ok got my ex back from the dealer.

this is what the tech wrote
"Suspect RCM may be causing high speed network fault, performed self test and retrieved DTCs. Network fault codes U1900-T, Test for U codes and could not determine any failure/performed pion-point test for P260F. Have to fix communication failure codes before diagnosing. Disconnected all Aftermarket radio accessories (my HAM Radio lol) and cleared all codes/Road tested and all lights came on and went into limp mode. Performed self test and when faults occurs the RCM will not communicate or self test. Cant determine cause because of such intermittent communication failure."

SO they think its the RCM "Restraints control module" Part: 9L2Z-14B321-A
Price $350~ from the dealer plus labor. $750 total.

So i was like ummm no.

So im gonna do a bunch more research and even take a look at the part my self in case maybe the connector is dirty or something. The Service guy at the deal was nice enough to print out the directions to replace the part. it is located under the back part of the center console.

Really sucks that my base care ESP plan doesnt cover that. Kinda stupid to think that a safety item like that is planned to go bad before 100K miles and unless you get the top of the line warranty it doesnt cover it.

weee looks like i have some fun ahead of me. Atleast as of right now its not acting up. I really think its heat related also it seems to happen more and sooner when the AC was on sense the RCM is right under where the floor vents are in the center console to going from like 110*F inside car temp to like 60*F cold AC that might do something.

 

[Themightyquinn]

Found something interesting about the U1900 fault code retrieved from the RCM. According to the Workshop Manual this is the under the action to take:
"NOTE:
DTC U1900 will set in a module that is reporting a communication fault from another module on the data bus. The module that reports the fault is not the problem module. Do not install a new RCM as part of repair for a RCM DTC U1900 fault.
VIEW and RECORD IC_MSG_RCM, PCM_MSG_RCM, and OCS_MSG_RCM fault PIDs to determine the module with the concern."

 

[banditxp]

Found something interesting about the U1900 fault code retrieved from the RCM. According to the Workshop Manual this is the under the action to take:
"NOTE:
DTC U1900 will set in a module that is reporting a communication fault from another module on the data bus. The module that reports the fault is not the problem module. Do not install a new RCM as part of repair for a RCM DTC U1900 fault.
VIEW and RECORD IC_MSG_RCM, PCM_MSG_RCM, and OCS_MSG_RCM fault PIDs to determine the module with the concern."

Thank you so much!!!!
i knew my gut feeling was right about it not being the RCM. i just didnt have any proof. Im gonna take it to another dealer and start fresh and see what they say and if they dont get to this point right away im gonna show them this.

 

[Themightyquinn]

Thank you so much!!!!
i knew my gut feeling was right about it not being the RCM. i just didnt have any proof. Im gonna take it to another dealer and start fresh and see what they say and if they dont get to this point right away im gonna show them this.

tell them that it's in 501-20B-20 in Volume 1 of the 2008 Explorer, Mountaineer, Explorer Sport Trac Workshop Manual.

 

[banditxp]

very cool. thanks again. that helps so much. I so wished i bough the service manuals last year. just never got around to it. i bought the wiring book but that doesn't help much in this case lol.

 

[Themightyquinn]

Print this out and show it to them. They are using the troubleshooting chart in the Module Communications Network. But since you have the airbag light, they should be using the troubleshooting chart in the Supplemental Restraint System section.

 

[Themightyquinn]

very cool. thanks again. that helps so much. I so wished i bough the service manuals last year. just never got around to it. i bought the wiring book but that doesn't help much in this case lol.

You can buy them off ebay for a fair price, however I got mine from a vendor at the Ford Carlisle nationals this past June from a vendor for dirt cheap.

Unless it does happen to be the RCM, it's prolly good to check wiring, fuses, grounds, grounding of the component cases, connenctor pins, and terminals.

 

[banditxp]

cool.

well from all the things that are going on im really thing its a problem with the PCM.
the other day when driving around it did it again where the Airbag, Wrench and engine light where on and it went into 3rd limp mode then a file miles later the TC light came on and the info center flash with "Service RSC Soon" message. so its like there is a big communication problem going on.

also when its not doing it the trans does not seem to shift the same as it used to and before it goes into limp mode i notice it shifts funny too. i can also kinda make it go into limp mode now. last night driving back home i was driving all nice and slow and easy and it was working fine. then i got on it a little bit ot get around a slow car shifted from 4th down to 2nd and then it stayed in 2nd till i pulled over and then it went into 3rd limp mode. that really doesnt sound like the RCM can make it do all that.

 

[Themightyquinn]

There is definately something screwy with your high speed controller area network. I've kinda got a feeling its something stoopid like a ground-out or something since it seems very erratic. The reason why I say that is because the you are having tranny problems. The TCM is on the High Speed-CAN as is the RCM and the OCSM (occupant classification system module) which monitors weight in the the front passenger seat which the RSM will determine if the passenger air bags need to be deployed or not in an accident. However the TCM doesn't communicate with either the RCM or the OCSM, it only communicates with the ABS module, 4x4 control module, PCM and instrument cluster. But the RCM also communicates with the PCM and IC. So having said that, the RCM and TCM both separately communicate with the PCM and IC. So maybe there might be something screwy with either the PCM or IC??? But if it was mine, i would tear the vehicle apart to reveal every module on the HS-CAN and do a visual inspection.

 

[Themightyquinn]

Also I found another place in the book thats states not to replace the module with a U1900 code, you need to go back to that dealer and tell their mechanics to start going by their manuals and not by their own way cuz they dont know ****. That kind of **** pisses me off.

 

[banditxp]

Cool thanks again

yea me to man. me too. if i had the book and a scan tool i would have done all the troubleshooting my self lol. but also sense i have an a ESP i wanted to try to make them fix it for free. I may go back to there. not sure if i trust them anymore sense there tech spent 2.5 hours on it and thats all he came up with.

 

[Themightyquinn]

ok got my ex back from the dealer.

this is what the tech wrote
"Suspect RCM may be causing high speed network fault, performed self test and retrieved DTCs. Network fault codes U1900-T, Test for U codes and could not determine any failure/performed pion-point test for P260F. Have to fix communication failure codes before diagnosing. Disconnected all Aftermarket radio accessories (my HAM Radio lol) and cleared all codes/Road tested and all lights came on and went into limp mode. Performed self test and when faults occurs the RCM will not communicate or self test. Cant determine cause because of such intermittent communication failure."

SO they think its the RCM "Restraints control module" Part: 9L2Z-14B321-A
Price $350~ from the dealer plus labor. $750 total.

So i was like ummm no.

So im gonna do a bunch more research and even take a look at the part my self in case maybe the connector is dirty or something. The Service guy at the deal was nice enough to print out the directions to replace the part. it is located under the back part of the center console.

Really sucks that my base care ESP plan doesnt cover that. Kinda stupid to think that a safety item like that is planned to go bad before 100K miles and unless you get the top of the line warranty it doesnt cover it.

weee looks like i have some fun ahead of me. Atleast as of right now its not acting up. I really think its heat related also it seems to happen more and sooner when the AC was on sense the RCM is right under where the floor vents are in the center console to going from like 110*F inside car temp to like 60*F cold AC that might do something.

That description from the tech didn't provide much info. There are 7 U1900 DTC faults because there are 7 modules that put out this code: the ACM (audio control module), DSM (driver seat module), instrument cluster, OCSM, PRB (power running board module if equipped), the RCM, and the 4x4 control module. Now he said the RCM wouldn't communicate or "self test". I cant find anywhere in the manual where it talks about a "self test" for the RCM. When you are performing the network test, the scan tool will first communicate with the PCM and then communicate with the rest of the modules. It says "If the network test passes, retrieve and record the continuous memory DTCs and proceed to the next step. If the network test fails, go to Symptom chart to identify the module not communicating"
So my question to him would be 'how are you getting DTCs if the network test is failing'?

 

[banditxp]

Very true. all great info i wish i knew ahead of time lol.
I think im gonna go buy a FSM after i get this fixed. hoping under my ESP warranty.

 

[banditxp]

So.. Ne Code U0101

I went back tot e dealer and showed them everything. they looked at it again and even called into the ford hotline. they still think its the RCM and they said they could not get any more codes from the RCM.

so the only way to prove to them that it was not the RCM was to unhook it and take that out of the loop. I did that last night and today driving around... guess what... starting doing all the same stuff again.

Went back to the dealer and they pulled that new U0101 code. They still wont give me a loaner till they prove its a warranty part. And they are swamped today from having the day off yesterday so they cant even look at it today.

Im about to go freaken nutz. need to be at work tomorrow and its a 55 mile drive form were i am now and i can not do that stuck in 3rd limp mode. also yea now it goes into limp mode much faster and pretty much every time when you drive.

I know its a warranty part because at this point its either the PCM, TCM or a wire problem and thats all under warranty. ugh.

 

[Themightyquinn]

im starting to think it is the rcm. And also by disconnecting even a good working rcm will throw fault codes and screw thinks up. The RCM receives data from and controls certain functions of other modules on the network. So without the RCM being able to talk on the HS-CAN, things get all fudged up. Since 2 dealers are saying it is the RCM, i would go ahead with it. But that still doesnt explain the TCM issue with being stuck in limp mode. And before you replace the RCM, Verify with the dealer, that they actually did the proper troubleshooting on the RCM itself. IE voltage checks, circuit resistance checks, ground checks, all the stuff that is in their workshop manuals. I'll look that new code up for you in the morning.

 

[banditxp]

i really think its not the RCM. i didnt take it to another dealer yet i took it back to the same to prove them wrong. im going ot a new dealer tomorrow if not monday.

The thing is the more i drive the more troubleshooting i do by doing so. Its pretty much acting the same way as before but now it seems to happen quicker and also i cant reset it as easy as before. i used to be able to stop. turnoff and back on and then be on my way. not its like 50/50 if that works.

The code when the dealer looked it up states that its something with the TCM not communicating in time with the PCM. in the possible causes it says check for bad CAN wire or connections.

 

[Themightyquinn]

Well according to my 2008 Workshop manual, U0101 is not listed on the network DTC chart. There is a U100 which is "lost communication with ECM/PCM". The source is the TCM. "The module could not communicate on the network at a point in time. The fault is currently not present. CLEAR the DTC. REPEAT the network test with a scan tool." Then there is a U0102 which is "lost communication with transfer case control module" also originating from the TCM. I think the dealer meant U0100 not U0101. You need to ask them whats up with that. Did they pull any codes related to the RCM the second time?

 

[banditxp]

nope, i was standing there when he scanned it and also when he looked it up in the computer. i saw it right on the screen.

also look at this
http://www.ford-trucks.com/forums/1104389-code-u0101-cant-communicate-tcm.html