Why will the obdII port will not speak with pcm
11-21-2011, 08:33 AM
#1
Why will the obdII port will not speak with pcm
as the title suggest, i am looking for all possible reasons this car's obII port will not connect to the pcm.
EXCLUDING:
Bad PCM, Power or grounds.
Other than those 3 what would keep the obII port from connecting?
Yes, the appropiate obII reader is being used.
I have pulled hair out over this
EXCLUDING:
Bad PCM, Power or grounds.
Other than those 3 what would keep the obII port from connecting?
Yes, the appropiate obII reader is being used.
I have pulled hair out over this
11-21-2011, 08:36 AM
#3
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Ah......what the hell.......even though you said it's appropriate..............what is the reader(exactly) and has it ever worked in the past?
My pure guess at this point Denny....depending on your answers is that you have a bent pin or it's not making good contact on both ends, or something like that.
What are you getting a communication error or nothing at all?
Also, if you ran up to autozone and asked them to read it(just for the hell of it.....or have access to a different scanner) that would eliminate a few things........providing they(or it) can read it.
My pure guess at this point Denny....depending on your answers is that you have a bent pin or it's not making good contact on both ends, or something like that.
What are you getting a communication error or nothing at all?
Also, if you ran up to autozone and asked them to read it(just for the hell of it.....or have access to a different scanner) that would eliminate a few things........providing they(or it) can read it.
11-21-2011, 08:47 AM
#4
Are you assuming it isn't connected to the PCM because your reader isn't picking anything up? Or because you have tested the leads with a multimeter and are getting no signal at all? You mention the 'appropriate obd2 reader' is being used ... well what is it? Remember our cars have an MSCAN and an HSCAN, some ELM devices have the leads mixed up to read MSCAN instead of HSCAN. What baud rate are you using? What data rate are you using? Lots of information is missing here for any of us to actually help you.
11-21-2011, 09:40 AM
#5
Sorry--I should have given more history/details.
the reader has been various ones including the dealerships ( who was NO help),
they thought is was a bad pcm but a new pcm was obtained and it still would not connect.
The obII port has apprpiate power ( 11.9 volts) at its pin and the grounds ( there are 2) are good. The can bus lines ( x 2) are showing various voltage of course and it is 3 to 4 IF I remember correctly. The safety system ( airbags/selt belt pre tensioner etc) is good.
The underdash electrical clip connector looks good and the wires resistances are 0.1 across the connector.
It is an advanced key car and of course the security system cannot talk to the commputer. This equals to a no crank condition. All the remote functions of the key work.
The battery is good and holds a charge of 12.5V with none to speak of leak down in the system. The dash pods ( instrutment clusters) are good.
Real head ache causing puzzle.
Its not my car but I am keeping it until the owner gets back from overseas.
I just can't let go of it
the reader has been various ones including the dealerships ( who was NO help),
they thought is was a bad pcm but a new pcm was obtained and it still would not connect.
The obII port has apprpiate power ( 11.9 volts) at its pin and the grounds ( there are 2) are good. The can bus lines ( x 2) are showing various voltage of course and it is 3 to 4 IF I remember correctly. The safety system ( airbags/selt belt pre tensioner etc) is good.
The underdash electrical clip connector looks good and the wires resistances are 0.1 across the connector.
It is an advanced key car and of course the security system cannot talk to the commputer. This equals to a no crank condition. All the remote functions of the key work.
The battery is good and holds a charge of 12.5V with none to speak of leak down in the system. The dash pods ( instrutment clusters) are good.
Real head ache causing puzzle.
Its not my car but I am keeping it until the owner gets back from overseas.
I just can't let go of it
11-21-2011, 10:10 AM
#7
The PCM could be "blank". If you installed a new PCM you usually have to program them first with "as built" data from Mazda.
The scan tool can communicate with everything else BUT the PCM? Meaning you can pull codes from all the other systems?
I was thinking you got all this figured out since we haven't heard from you lately about this car!
The scan tool can communicate with everything else BUT the PCM? Meaning you can pull codes from all the other systems?
I was thinking you got all this figured out since we haven't heard from you lately about this car!
11-21-2011, 11:23 AM
#8
Lol--i sold the car for a very reasonable price and I am just keeping it for someone. But, when I have time I am trying to help him out. He is fully aware of the problem and the selling price you would not have believed:0 But that is OK.
It is the same issue that has never been solved. yet a LOT of work has gone on trying to get it solved
Now I did solve the safety system stuff and appreciate everyones help with that. I then drove the car for a few hundred miles and it ran flawlessly, no codes --nothing. I had the car inspected and obtained the title. Then I went to crank it one morning and this is what I have.
Update:
I have the oridginal computer back in the car. I did open it and it looks pristine. The Mazda dealership told me a new computer was needed after working with it for a day. I got one. Towed the car back to them , they installed it and then said the obII port wasnt working ( the wiring to the port is good and the pins are good) so they could not load any build data. I never believed it needed a new pcm anyway. They wanted another $2000 to buy a harness. they had the throw parts at it until its fixed mentality. So I towed it home and reinstalled the ordiginal pcm. So, I was fustrated and feed up so I sold the car with full disclosure for a very cheap price.
Meanwhile, I have been very very puzzled about it and am trying to help the new owner out.
I believe if I can get the obII port to connect, then progress can be made.
The security system still flashes the 1- 6 code--no communication with the pcm. The keyless function works well as well as all locks etc.
The obII port has good power and grounds, the connector from the port that sends the wires through the interior firewall is good. The connector/ wires resistance is acceptable at 0.1?
Somewhere there is a little something that I have missed............. IDK. i dont want to just replace everything. I want to understand what the heck happened.
Its my curse
It is the same issue that has never been solved. yet a LOT of work has gone on trying to get it solved
Now I did solve the safety system stuff and appreciate everyones help with that. I then drove the car for a few hundred miles and it ran flawlessly, no codes --nothing. I had the car inspected and obtained the title. Then I went to crank it one morning and this is what I have.
Update:
I have the oridginal computer back in the car. I did open it and it looks pristine. The Mazda dealership told me a new computer was needed after working with it for a day. I got one. Towed the car back to them , they installed it and then said the obII port wasnt working ( the wiring to the port is good and the pins are good) so they could not load any build data. I never believed it needed a new pcm anyway. They wanted another $2000 to buy a harness. they had the throw parts at it until its fixed mentality. So I towed it home and reinstalled the ordiginal pcm. So, I was fustrated and feed up so I sold the car with full disclosure for a very cheap price.
Meanwhile, I have been very very puzzled about it and am trying to help the new owner out.
I believe if I can get the obII port to connect, then progress can be made.
The security system still flashes the 1- 6 code--no communication with the pcm. The keyless function works well as well as all locks etc.
The obII port has good power and grounds, the connector from the port that sends the wires through the interior firewall is good. The connector/ wires resistance is acceptable at 0.1?
Somewhere there is a little something that I have missed............. IDK. i dont want to just replace everything. I want to understand what the heck happened.
Its my curse
11-21-2011, 01:16 PM
#11
How would the advanced key keep the port from communicating with the pcm?
The advanced key is working fine--no problems with it that I know off. It turns on the keyless start feature, it unlocks the door as i approach etc etc.l
The security system also cannot communicate with the pcm. It is part of the can bus flow---i think ---and all can bus flow is shared with pcm--right? Dont they have a symbiotic relationship?
So if I can get the port to work--then maybe some progress can be made?
I dont know why I cant let this go!!!!!!!!!!!!
I have checked voltage on the can bus lines--how do I check the info flow? What do I need to do that?
yea this is the same R3 It is a very beatiful car. This head ache problem will be fixed. It has 9K miles on it. Interior still smells brand new. I have had it in storage and under protection/wrap and it is off the ground.
The advanced key is working fine--no problems with it that I know off. It turns on the keyless start feature, it unlocks the door as i approach etc etc.l
The security system also cannot communicate with the pcm. It is part of the can bus flow---i think ---and all can bus flow is shared with pcm--right? Dont they have a symbiotic relationship?
So if I can get the port to work--then maybe some progress can be made?
I dont know why I cant let this go!!!!!!!!!!!!
I have checked voltage on the can bus lines--how do I check the info flow? What do I need to do that?
yea this is the same R3
It is a very beatiful car. This head ache problem will be fixed. It has 9K miles on it. Interior still smells brand new. I have had it in storage and under protection/wrap and it is off the ground.
11-21-2011, 02:51 PM
#12
"It is an advanced key car and of course the security system cannot talk to the commputer"
"How would the advanced key keep the port from communicating with the pcm?"
You are contradicting yourself here and overcomplicating the entire situation at the moment. Take a minute and restructure what you are saying.
Dont think of the obd2 connector as a "port" ... it doesn't do anything special, it is essentially wires that are tapped in parallel with the bus, there is no magic going on there. Remember that the OBD lines are part of a bus, and it is bidirectional. What does this mean? It means that ANYTHING can corrupt the bus and either cause an overflow or cause dropped packets. Now, before you rule out the AKM, thing about it ... what is actually controlling the start/stop/unlock/arm etc functions ? digital functions (canbus) or electrical funtions ... I am guessing the latter ... which means that although pressing the "lock" button locks the car, it doesn't mean that the data being logged onto the BUS is valid.
You also mention the "security system cannot communicate with the pcm" ... my question to you is ... why would it? What data should be on that bus from the security system? What are you expecting to see? What are you actually seeing? How have you confirmed that there is no data.
Also understand that you are not going to see all data on the bus. Certain data is masked off and can only be accessed via extended bus messaging. Things like the security system, ABS system, transmission, cruise control, and tpms system are all on separate ECU's that are at seperate addresses. They will not post messages to the default masked bus, so unless you are requesting extended data, and know exactly what the send and recieve address (they are different) is, you really have no legitimate way knowing if there is messages on the bus.
I am failing to really understand how you have established that there is no communication on the bus. I assure you there is data flowing on the bus or else your car wouldn't be operating worth a damn. The question is, what ECU is failing to communicate (if any), or what ECU is sending corrupt packets (if any).
Neither of the above questions can be answered easily without digging into the bus with an ELM device or an OBD2 interpreter.
"How would the advanced key keep the port from communicating with the pcm?"
You are contradicting yourself here and overcomplicating the entire situation at the moment. Take a minute and restructure what you are saying.
Dont think of the obd2 connector as a "port" ... it doesn't do anything special, it is essentially wires that are tapped in parallel with the bus, there is no magic going on there. Remember that the OBD lines are part of a bus, and it is bidirectional. What does this mean? It means that ANYTHING can corrupt the bus and either cause an overflow or cause dropped packets. Now, before you rule out the AKM, thing about it ... what is actually controlling the start/stop/unlock/arm etc functions ? digital functions (canbus) or electrical funtions ... I am guessing the latter ... which means that although pressing the "lock" button locks the car, it doesn't mean that the data being logged onto the BUS is valid.
You also mention the "security system cannot communicate with the pcm" ... my question to you is ... why would it? What data should be on that bus from the security system? What are you expecting to see? What are you actually seeing? How have you confirmed that there is no data.
Also understand that you are not going to see all data on the bus. Certain data is masked off and can only be accessed via extended bus messaging. Things like the security system, ABS system, transmission, cruise control, and tpms system are all on separate ECU's that are at seperate addresses. They will not post messages to the default masked bus, so unless you are requesting extended data, and know exactly what the send and recieve address (they are different) is, you really have no legitimate way knowing if there is messages on the bus.
I am failing to really understand how you have established that there is no communication on the bus. I assure you there is data flowing on the bus or else your car wouldn't be operating worth a damn. The question is, what ECU is failing to communicate (if any), or what ECU is sending corrupt packets (if any).
Neither of the above questions can be answered easily without digging into the bus with an ELM device or an OBD2 interpreter.
11-21-2011, 03:38 PM
#13
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Dude, he's got a meter and scanner at best..........give him a break. You are talking way over what the "normal" person could comprehend.............No offense Denny.
I need to go back and read all that has been said, but we gotta work from basics here first.
Oh......and this was the submarine vehicle right? That should be a huge clue there, or at least something we have to eliminate. By that I mean water/corrosion possibly on many, many harnesses.
When I get home tonight I'll do some research and see what I can come up with........but that will be after catching up on all that has been tried to this point.
I need to go back and read all that has been said, but we gotta work from basics here first.
Oh......and this was the submarine vehicle right? That should be a huge clue there, or at least something we have to eliminate. By that I mean water/corrosion possibly on many, many harnesses.
When I get home tonight I'll do some research and see what I can come up with........but that will be after catching up on all that has been tried to this point.
11-21-2011, 04:10 PM
#14
I appreciate the attempt to help and i do understand a lot of what you are saying. But not all!
When I said the security system cant connect with the pcm--that is the code the security system is flashing: 1 light followed by 6 lights--repeating.
It was a flood car--water did not touch the bottom of the seats There is really very little wiring down that low and it has to do with the airbags/self belt pre tensioners. That was fixed and is operational. No problems
Now i realize that a short or "surge " can instantly affect other componets that water didnt touch but the car was running fine for a while, then suddenly stopped. Logic tells me that the components at that time were all ok?
I also realize that resistance could be an issue, but so far that is checking out oK. I did remove the entire interior of the car and harness when it was being repaired. It checked out fine after the repair and ran well for a while afterward.
Even now everything turns on in the car, all dash lights work well, headlights, brakelights, stereo, heat controls, interior lights, etc.
Now as far as can bus info, i understand its a parrellel connection, with packets of info that take turns in using the line. I understand that perhaps the data is corrupt? But which data and how do you check that when nothing will connect--not even the dealerships equipment?
Is this just one of those situations in which parts just have to be thrown in there until its fixed?
I HATE THAT.
hell may just install a Haltech.
Any help/thoughts are appreciated.
Oh by the way--i identified its an advanced key car because the wiring is different with that option.
When I said the security system cant connect with the pcm--that is the code the security system is flashing: 1 light followed by 6 lights--repeating.
It was a flood car--water did not touch the bottom of the seats There is really very little wiring down that low and it has to do with the airbags/self belt pre tensioners. That was fixed and is operational. No problems
Now i realize that a short or "surge " can instantly affect other componets that water didnt touch but the car was running fine for a while, then suddenly stopped. Logic tells me that the components at that time were all ok?
I also realize that resistance could be an issue, but so far that is checking out oK. I did remove the entire interior of the car and harness when it was being repaired. It checked out fine after the repair and ran well for a while afterward.
Even now everything turns on in the car, all dash lights work well, headlights, brakelights, stereo, heat controls, interior lights, etc.
Now as far as can bus info, i understand its a parrellel connection, with packets of info that take turns in using the line. I understand that perhaps the data is corrupt? But which data and how do you check that when nothing will connect--not even the dealerships equipment?
Is this just one of those situations in which parts just have to be thrown in there until its fixed?
I HATE THAT.
hell may just install a Haltech.
Any help/thoughts are appreciated.
Oh by the way--i identified its an advanced key car because the wiring is different with that option.
Last edited by olddragger; 11-21-2011 at 04:12 PM.
11-21-2011, 04:10 PM
#15
eh, i really didn't talk in any way that would require special knowledge of the system ... but regardless no offense taken ... let me "normal" it up then based on this comment:
"It is an advanced key car and of course the security system cannot talk to the commputer. This equals to a no crank condition. All the remote functions of the key work."
How have you established that the advanced key has anything to do with the car not starting. Is it feasible that something else is causing the issue? If not, why do you think that?
edit: looks like we posted at the same time ... one sec while i read...
"It is an advanced key car and of course the security system cannot talk to the commputer. This equals to a no crank condition. All the remote functions of the key work."
How have you established that the advanced key has anything to do with the car not starting. Is it feasible that something else is causing the issue? If not, why do you think that?
edit: looks like we posted at the same time ... one sec while i read...
11-21-2011, 04:15 PM
#16
Heres the thing, the obd2 bus has many "areas". Think of it like a highway. General information like engine data that an accessport or scangauge reads is over in "Lane 1". OBD fault codes and such are wayyyyyyy over in "Lane 9". For all we know, lane 9 might be corrupt while the rest of the highway is still open.
The only way you can read this is to get yourself an OBD2 reader (not a code scanner). Just get one of those cheap chinese ELM devices and I can help you read the data on the bus and translate it. We can then compare the information against what is on my bus and look for any anomalies.
Granted this is a more "Advanced" approach, it would at least let us know exactly what the car is thinking.
For the light sequence to be showing on your dash means that portions of the bus are intact, as those signals are passed through the canbus.
hope that helps
11-21-2011, 04:19 PM
#17
Well the security light is flashing code #16.
If you look at the troubleshooting tree for that code in the workshop manual, it is not very long. First step is, determine if there are any other additional network trouble codes present. If there are, go to appropriate troubleshooting tree and find network issue.
If there aren't any network codes, it says to replace the Keyless Control Module, following the correct replacement procedure, meaning you need two keys. Then rescan for codes. If the code #16 is present again or some additional codes listed on the workshop manual, replace PCM.
Without a "dealer level" type scan tool and code retrieval, can't really help much. Find someone local with an Autoenginuity and buy the Mazda enhanced code access? Or make good friends with a Mazda tech?
If you look at the troubleshooting tree for that code in the workshop manual, it is not very long. First step is, determine if there are any other additional network trouble codes present. If there are, go to appropriate troubleshooting tree and find network issue.
If there aren't any network codes, it says to replace the Keyless Control Module, following the correct replacement procedure, meaning you need two keys. Then rescan for codes. If the code #16 is present again or some additional codes listed on the workshop manual, replace PCM.
Without a "dealer level" type scan tool and code retrieval, can't really help much. Find someone local with an Autoenginuity and buy the Mazda enhanced code access? Or make good friends with a Mazda tech?
11-22-2011, 03:18 AM
#19
Super Moderator
Dealers use WDS or now MMDS, which does everything including re-programming PCM's..
At this end they do not use the simple ODB scan devices we use, unfortunately Dealers will go through a "troubleshooting"/"possible factor" schedule with removed this or renew that part, but how many parts are they willing to replaced when most Dealers don't even stock these expensive bits..
A Dealer should also be able to test modules with their WDS oscilloscope, I guess so much depends on the techs competence and how much time they are prepared to spend on the car.
But again, the Dealer has on-line access to instruct them on what to do...blow by blow part by part.
Denny, can you PM me the VIN on this car the JM1--------------.
I can now search by VIN and see what parts your car has and IF there are some recent changes made to individual modules which sometimes can be an indication of issues with "a" particular part or module.
Honestly, these AKE's are more trouble than they are worth...no offense to AKE owners.
At this end they do not use the simple ODB scan devices we use, unfortunately Dealers will go through a "troubleshooting"/"possible factor" schedule with removed this or renew that part, but how many parts are they willing to replaced when most Dealers don't even stock these expensive bits..
A Dealer should also be able to test modules with their WDS oscilloscope, I guess so much depends on the techs competence and how much time they are prepared to spend on the car.
But again, the Dealer has on-line access to instruct them on what to do...blow by blow part by part.
Denny, can you PM me the VIN on this car the JM1--------------.
I can now search by VIN and see what parts your car has and IF there are some recent changes made to individual modules which sometimes can be an indication of issues with "a" particular part or module.
Honestly, these AKE's are more trouble than they are worth...no offense to AKE owners.
11-22-2011, 09:02 AM
#21
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In certain cases they might have to throw one or two things at it in order to get some response that will lead them down a certain path. I understand what you are saying, but sometimes it's all they have. This actually might be one of those cases. Electrical gremlins(while possibly not technically correct in this case, we shall see) can be very, very tricky as you well know.
Didn't really get a chance to revierw anything last night, but you're getting some good help from several at this point. I'm curious if you could find out exactly what system the dealer was attempting to use that was a no go?
Didn't really get a chance to revierw anything last night, but you're getting some good help from several at this point. I'm curious if you could find out exactly what system the dealer was attempting to use that was a no go?
11-22-2011, 10:12 PM
#23
Super Moderator
Got it mate...
Velocity Red with Black Interior made before March 3rd 2009.
In fact 290 RX-8's after mine in August 2008.
Now lets see if I can find out anything parts wise..
Will get back ASAP.
Velocity Red with Black Interior made before March 3rd 2009.
In fact 290 RX-8's after mine in August 2008.
Now lets see if I can find out anything parts wise..
Will get back ASAP.
11-22-2011, 11:47 PM
#24
Super Moderator
Parts Comparison of Denny's 09 Modules to later S2's
Denny, Got your VIN number details, I just thought I would go through ALL the changes to the electronics on the Series 2 USA model and your 09, just to see what may have changed and perhaps what may help you to look in what area's.
Having said this it could be a complete waste of time and I am totally useless, just trying to chuck some idea's out there..
Just adding the bleeding obvious, just to perhaps jog your mind Denny IF some or ANY parts have been changed for whatever reasons???
This is not in any particular order..
The New PCM Mazda Dealer should have used, repeat should have, is N3R7-18-881M ($605.79 USD)
Yours has a Manual Air Con System, the Auto Climate Air Con Control Amp Modules and Switches are different.
NO Auto Headlights on or Rain Sensing Wipers.
Having said this it could be a complete waste of time and I am totally useless, just trying to chuck some idea's out there..
Just adding the bleeding obvious, just to perhaps jog your mind Denny IF some or ANY parts have been changed for whatever reasons???
This is not in any particular order..
The New PCM Mazda Dealer should have used, repeat should have, is N3R7-18-881M ($605.79 USD)
Yours has a Manual Air Con System, the Auto Climate Air Con Control Amp Modules and Switches are different.
NO Auto Headlights on or Rain Sensing Wipers.
Last edited by ASH8; 11-23-2011 at 12:12 AM.
