Help ! C5 Speedometer not registering MPH !
Thread Starter
Intermediate
Joined: Feb 2013
Posts: 34
Likes: 1
From: Norwich Norfolk
Almost ! I would say the seal has been compromised judging by the sound of particles inside it.
I think someone has been there before me recently, all the fasteners came out easily, including the four that hold the PCM halves together, I decided not to split it as that would render the car immobile and it may take a couple of weeks to get another shipped from the States.
I'll split it then just out of curiosity.
I like to thank you guys for all your help with this, I needed a direction to start in and you gave it to me.
I'll post the outcome of the PCM switch when I have done it.
I think someone has been there before me recently, all the fasteners came out easily, including the four that hold the PCM halves together, I decided not to split it as that would render the car immobile and it may take a couple of weeks to get another shipped from the States.
I'll split it then just out of curiosity.
I like to thank you guys for all your help with this, I needed a direction to start in and you gave it to me.
I'll post the outcome of the PCM switch when I have done it.
Race Director
Joined: Apr 2007
Posts: 11,150
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From: South Western Ontario
There's a learning procedure to reset the BCM-PCM handshake to make the security work. It involves turning the key on and waiting 11 minutes between and then repeating 3 times. I'll try to look it up tonight and post it. Send me a message if I forget. It should be fairly easy to find here too.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Yeah, sounds like the PCM needs to be replaced. It may not be the problem (probably is) but you don't want it to go completely south later when you are out driving. I would replace it and if it does not fix the issue we can review the next option.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
The relearn procedure goes like this.
Turn key on and wait 11 minutes.
Turn key off and wait 30 seconds.
Repeat the above steps 2 more times. At the end of the 3rd 11 minutes on you should get a code P1630 set.
Turn the key on and wait 30 seconds.
Attempt to start the car.
Turn key on and wait 11 minutes.
Turn key off and wait 30 seconds.
Repeat the above steps 2 more times. At the end of the 3rd 11 minutes on you should get a code P1630 set.
Turn the key on and wait 30 seconds.
Attempt to start the car.
Thread Starter
Intermediate
Joined: Feb 2013
Posts: 34
Likes: 1
From: Norwich Norfolk
OK, I received my replacement PCM from Flashmasters in Ohio. Had it fitted in half an hour, as predicted the PCM-BCM password has to be relearned.
This is now where the problem lies, I have done the procedure three times and each time it throws the same code P1631 = Theft deterrent System password incorrect.
The car starts and then dies immediately, I have the procedure on a print out and at the top of the section it says, "Important: This step is for United States and Canada vehicles only"
It also says that the 11 mins and 30 secs are a minimum required amount, the time limit can be exceeded without interfering with the procedure, so I have been giving it a couple of seconds longer on each stage. Also, I read somewhere that early cars are a "10 mins and 10 seconds" procedure, but what constitutes an early car ? Mine is a '99MY
Could there be a different procedure for European spec Corvettes ?
This is now where the problem lies, I have done the procedure three times and each time it throws the same code P1631 = Theft deterrent System password incorrect.
The car starts and then dies immediately, I have the procedure on a print out and at the top of the section it says, "Important: This step is for United States and Canada vehicles only"
It also says that the 11 mins and 30 secs are a minimum required amount, the time limit can be exceeded without interfering with the procedure, so I have been giving it a couple of seconds longer on each stage. Also, I read somewhere that early cars are a "10 mins and 10 seconds" procedure, but what constitutes an early car ? Mine is a '99MY
Could there be a different procedure for European spec Corvettes ?
Last edited by V8 YEA; Feb 23, 2013 at 06:29 AM.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
I just looked in my FSM. It does not say whether it is just for USA or any country. The Theft Deterrent section does not speak to any differences between countries. Where did you get your instructions from? However, with that said my FSM provides a 10 min and a 30 min learn procedure. It does not say why there are two. Anyway, here it is. Give it a try and maybe it will work. If not we'll figure it out.
Thread Starter
Intermediate
Joined: Feb 2013
Posts: 34
Likes: 1
From: Norwich Norfolk
OK, I tried the 30 minute proceedure, still no joy , same code P1631 coming up.
I did note in the instructions you gave me that it said the security lamp would go off in within the 10 minute period, well mine goes out almost straight away, as if there is no problem with the security.
I did note in the instructions you gave me that it said the security lamp would go off in within the 10 minute period, well mine goes out almost straight away, as if there is no problem with the security.
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Race Director
Joined: Apr 2007
Posts: 11,150
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From: South Western Ontario
When is the code set?
Do you try to start it or not when beginning the procedure? My manual CD with all years does not say to attempt to start the earlier cars 97-00. The one posted is the 01-04 procedure.
Did you turn on the key and wait 30 seconds before trying to start after the 3rd on-off cycle?
Also, you did clear any codes before starting?
Do you try to start it or not when beginning the procedure? My manual CD with all years does not say to attempt to start the earlier cars 97-00. The one posted is the 01-04 procedure.
Did you turn on the key and wait 30 seconds before trying to start after the 3rd on-off cycle?
Also, you did clear any codes before starting?
Thread Starter
Intermediate
Joined: Feb 2013
Posts: 34
Likes: 1
From: Norwich Norfolk
When is the code set?
Do you try to start it or not when beginning the procedure? My manual CD with all years does not say to attempt to start the earlier cars 97-00. The one posted is the 01-04 procedure.
Did you turn on the key and wait 30 seconds before trying to start after the 3rd on-off cycle?
Also, you did clear any codes before starting?
Do you try to start it or not when beginning the procedure? My manual CD with all years does not say to attempt to start the earlier cars 97-00. The one posted is the 01-04 procedure.
Did you turn on the key and wait 30 seconds before trying to start after the 3rd on-off cycle?
Also, you did clear any codes before starting?
My attempt today was with the 10 minute method and I did start it initially.
As I said before, the security telltale doesn't stay on for longer than it normally would, so is the 97-00 method the 11 mimute version ??
I'll have another go tomorrow as it's getting dark here, snowing, and around -1oC in the workshop !
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Thanks Lionelhutz for helping. V8 Yea, try disconnecting the battery again before the next try and see if there is any affect. There has to be a simple solution for this. We'll stick with you until we figure it out.
Thread Starter
Intermediate
Joined: Feb 2013
Posts: 34
Likes: 1
From: Norwich Norfolk
I tried again today (twice) no luck ! I also took the original PCM apart and cleaned the case inside and out, the acid doesn't seem to have touched the circuit board, I reassembled it, put it back on the car and it fired right up !
I then took it up the road, still no speedo function, and the one code 1743 again loss of speed signal.
I'll phone the dealer tomorrow and see what he thinks.
I then took it up the road, still no speedo function, and the one code 1743 again loss of speed signal.
I'll phone the dealer tomorrow and see what he thinks.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
It would appear that your replacment PCM will not correctly share passwords with the BCM. I would discuss with the vendor.
With that said, I am trying to find out if the DIC cruise mph reading/display comes from the same source as what feeds the speedometer and HUD.
With that said, I am trying to find out if the DIC cruise mph reading/display comes from the same source as what feeds the speedometer and HUD.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Check the dark green/white wire from the PCM connector 2, pin 50. My guess is that it is damaged from the acid and not passing the speed signal to the RTD or cluster.
AFAIK, the HUD uses the same signal as the speedo. All passed via the above mentioned wire. The cruise is done in the PCM and the setting is passed to the DIC via serial data through the BCM.
AFAIK, the HUD uses the same signal as the speedo. All passed via the above mentioned wire. The cruise is done in the PCM and the setting is passed to the DIC via serial data through the BCM.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
I just finished searching for about 2 hours and I am in agreement with Lionelhutz. The PCM output is not getting to the instrument cluster. I can scan the PCM and IPC connector pin views and numbering for you. The IPC pin is A7. I know it will suck, but you need to pull both and check for an open ciruit or high resistance. Hopefully it is not internal to the IPC.
If you want to prove to yourself that the "set" DIC cruise mph is sent differently you can do the following: Set cruise in a gear that will challenge the engine, go up a hill and stress the engine so you know the speed is dropping, I bet the DIC reading will not change.
If you want to prove to yourself that the "set" DIC cruise mph is sent differently you can do the following: Set cruise in a gear that will challenge the engine, go up a hill and stress the engine so you know the speed is dropping, I bet the DIC reading will not change.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Here is the PCM Connector C2 picture. Hopefully you can find an issue with pin 50 and don't have to go to the IPC connector. It is on the top left row about halfway. If you can't ID connector C2 from C1 look for the dark green and white wire on one of them in this general location. Good luck, Sam. Let me know if you need anything else at this point.
Thread Starter
Intermediate
Joined: Feb 2013
Posts: 34
Likes: 1
From: Norwich Norfolk
Many thanks for the last diagram ! I will have a close look at that pin and corresponding connector today, I have already had the battery mount out and checked all the connectors situated therein. all OK, I will check that pin and try to find which 20 pin connector it ends in and check continuity.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Here is a picture of the IPC connector. Pin A7 is the one in question. I think to access this connector you will need to remove a lot of things including the console. There are some good links on getting to the IPC which take you through it all including good pictures. I presently have removed the console and knee bolster in preperation for replacing the multifunction switch. It all sounds more difficult than it is. Unplugging some of the connectors was difficult but just be patient.I will try to next post at a least one guide for getting to the IPC.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Here is the guidance I used (at least up to the actual IPC removal). Like I said some of the connectors were difficult to remove. However I am putting in a new CD radio and HVAC unit which were the difficult connectors. You don't need to remove these. If you have any problems let me know since I don't plan to finish my project for several weeks.
I would suggest you make sure all your dash lights are working since to get to the connector will have you 95% or better to being able to replace bulbs. Just know that the 2 main bulbs on each side are UV (special) bulbs. I don't have a part number or resource for these at this time.
PS: When removing the knee bolster the last step is to release the left top side. I had trouble with it but it came loose and I did not break the plastic tab. I think I had to pull down and not straight out. Will look at it again and try to help clarify removal so you don't break anything. Also, step 9c shows the IPC connector
http://www.vetteessentials.com/instr...zel_howto.html
I would suggest you make sure all your dash lights are working since to get to the connector will have you 95% or better to being able to replace bulbs. Just know that the 2 main bulbs on each side are UV (special) bulbs. I don't have a part number or resource for these at this time.
PS: When removing the knee bolster the last step is to release the left top side. I had trouble with it but it came loose and I did not break the plastic tab. I think I had to pull down and not straight out. Will look at it again and try to help clarify removal so you don't break anything. Also, step 9c shows the IPC connector
http://www.vetteessentials.com/instr...zel_howto.html
Last edited by dadaroo; Feb 26, 2013 at 08:08 AM. Reason: Add note on step 9c