OBD! CODE 54: ECM and TCM not Communicating
#1
OBD! CODE 54: ECM and TCM not Communicating
I should have posted this to section, so I apologize for the mis -post inthe main forum. My friend hooked a hand-held diagnostic computer to my car and there were no codes from the the trans. Below is the short version of what I know.
1993 300ZX 2+2 NA AT stock
* Automatic trans will not shift to second except manually bu letting off the gas and then applying at the proper RPM's
* No codes from trans; solenoids are turning ON and OFF when appropriate
* The engine threw a CODE 54 (NISSAN OBD1) "ECM and TCM not Communicating"
* Looked under car and there is a wire that appears to have melted against the exhaust
* Trans is mechanically sound and is shifting, it's just the engine appears to not know what is going on: you can see on the computer that it shifts as high as 4th (cannot go faster than 40-50mph)
I did call a trans shop and they said to check fuses or the harness, but how?
So, my question is how can I repair this without taking it in and how much will it cost me -- how should I go about checking the ECM (I know it is behind the floor board on the passenger side). I have friend that can do the job, but he needs to know what to do.
OR
If there is a good Z Shop or transmission shop in the Bay Area (California) I should take it in to -- got quoted $85 just to look at the car based on all the above info.
FYI: I do have a dealer repair manual, so I can find out where everything is at.
Thanks for any information and help.
1993 300ZX 2+2 NA AT stock
* Automatic trans will not shift to second except manually bu letting off the gas and then applying at the proper RPM's
* No codes from trans; solenoids are turning ON and OFF when appropriate
* The engine threw a CODE 54 (NISSAN OBD1) "ECM and TCM not Communicating"
* Looked under car and there is a wire that appears to have melted against the exhaust
* Trans is mechanically sound and is shifting, it's just the engine appears to not know what is going on: you can see on the computer that it shifts as high as 4th (cannot go faster than 40-50mph)
I did call a trans shop and they said to check fuses or the harness, but how?
So, my question is how can I repair this without taking it in and how much will it cost me -- how should I go about checking the ECM (I know it is behind the floor board on the passenger side). I have friend that can do the job, but he needs to know what to do.
OR
If there is a good Z Shop or transmission shop in the Bay Area (California) I should take it in to -- got quoted $85 just to look at the car based on all the above info.
FYI: I do have a dealer repair manual, so I can find out where everything is at.
Thanks for any information and help.
#2
well, first things first, if u see something broken, fix it.
repair the wire that looks melted.
Next, DL the FSM and follow the Troubleshooting guide.
Push comes to shove u might need to replace some wires and/or the TCM.
repair the wire that looks melted.
Next, DL the FSM and follow the Troubleshooting guide.
Push comes to shove u might need to replace some wires and/or the TCM.
#3
Safe Mode
I checked all the wiring and everything looked good: cleaned a few of the, rerouted the wiring and replaced the shielding and nothing has changed.
Now, my battery died a few months ago and I did replace it and I have read that can cause the ECU to go into safe mode, but the vehicle ran long enough to reset anything.
I had another mechanic tell me that the car might be in SAFE MODE since it is not throwing a CODE 55.
How do I go about reseting or clearing the code? There are currently no other codes being thrown. I have seen some information on other sites, butnothing that really explains anythin gin great deatail.
Thank you again for all the great responses.
Now, my battery died a few months ago and I did replace it and I have read that can cause the ECU to go into safe mode, but the vehicle ran long enough to reset anything.
I had another mechanic tell me that the car might be in SAFE MODE since it is not throwing a CODE 55.
How do I go about reseting or clearing the code? There are currently no other codes being thrown. I have seen some information on other sites, butnothing that really explains anythin gin great deatail.
Thank you again for all the great responses.
#4
go to autozone and ask them to read your OBD1 codes. then ask them to clear them.
as for the safe mode deal, i don't know personally but i do know i've seen a thread about it here on z-driver. search and i'm sure you'll find it.
as for the safe mode deal, i don't know personally but i do know i've seen a thread about it here on z-driver. search and i'm sure you'll find it.
Thread
Thread Starter
Forum
Replies
Last Post
Bookmarks