Help Please - mad electrical issues with 98 M6 vert
Thread Starter
Heel & Toe
Joined: Nov 2006
Posts: 15
Likes: 0
From: Melbourne Victoria
Help Please - mad electrical issues with 98 M6 vert
Hi all, only my 2nd post but a frustrating one. 
I have the dreaded P1751 ASR desired torque and no comm with the TCS. I must firstly say that I have done extensive searches including the extensive electrical sticky and have had no success. As far as I can ascertain the P1751 knocks out the TCS and ABS as these are both off line with the appropriate warning messages re 'active handling', service traction control, and service ABS.
Firstly let me tell you all what I have done to try and resolve this:
After reading Bill's informative posts (and others) on electrical problems I pulled all grounds apart, thoroughly cleaned and brushed them - found no signs of corrosion or damage. Next was the wheel sensors, harnesses (all female pins looked good and with good tension). Replaced the ETBCM module a couple of months ago so I'm hoping it hasn't gone for lunch. Anyway pulled the harness and checked all the pins for connection in fact have pulled most harness connectors I can find - all appear ok.
If I can tell you how the problem first started it may lead to a clue that I have missed. The car is mainly used for track days and after going through my previous set of Toyo RA1s, I decided to buy another set however the only sizing here in Aussie that was in the Proxes R888s (diff tread design to previos ones) that was close to fitting my aftermarket ZO6 rims was 255/40ZR17 front and 295/30ZR18 - now when I checked the outside OD the fronts were I mm taller than the rears. After taking the car for a run I had the following codes on the TCS module :
C1225, C1226 current codes both front wheel excessive speed variation
C1232, C1233, C1234 & C1235 H & C all wheel speed circuits shorted or open
C1255 H & C EBTCM internal malfunction ( not again
)
Do you think the wheel sizing had anything to do with anything?
I've since put the original wagon wheels and tyres on and after clearing all codes I'm stuck with P1751 and No Comm on the TCS.
I'm not sure where to go next as Tech 2's with the corvette software are rare as rocking horse s##t here and there is no corvette 'stealerships' either.
I'm sorry about the length of the post but I am desperate - oh yeah the battery is new also.
I have the dreaded P1751 ASR desired torque and no comm with the TCS. I must firstly say that I have done extensive searches including the extensive electrical sticky and have had no success. As far as I can ascertain the P1751 knocks out the TCS and ABS as these are both off line with the appropriate warning messages re 'active handling', service traction control, and service ABS.Firstly let me tell you all what I have done to try and resolve this:
After reading Bill's informative posts (and others) on electrical problems I pulled all grounds apart, thoroughly cleaned and brushed them - found no signs of corrosion or damage. Next was the wheel sensors, harnesses (all female pins looked good and with good tension). Replaced the ETBCM module a couple of months ago so I'm hoping it hasn't gone for lunch. Anyway pulled the harness and checked all the pins for connection in fact have pulled most harness connectors I can find - all appear ok.
If I can tell you how the problem first started it may lead to a clue that I have missed. The car is mainly used for track days and after going through my previous set of Toyo RA1s, I decided to buy another set however the only sizing here in Aussie that was in the Proxes R888s (diff tread design to previos ones) that was close to fitting my aftermarket ZO6 rims was 255/40ZR17 front and 295/30ZR18 - now when I checked the outside OD the fronts were I mm taller than the rears. After taking the car for a run I had the following codes on the TCS module :
C1225, C1226 current codes both front wheel excessive speed variation
C1232, C1233, C1234 & C1235 H & C all wheel speed circuits shorted or open
C1255 H & C EBTCM internal malfunction ( not again
)Do you think the wheel sizing had anything to do with anything?
I've since put the original wagon wheels and tyres on and after clearing all codes I'm stuck with P1751 and No Comm on the TCS.
I'm not sure where to go next as Tech 2's with the corvette software are rare as rocking horse s##t here and there is no corvette 'stealerships' either.
I'm sorry about the length of the post but I am desperate - oh yeah the battery is new also.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Hi all, only my 2nd post but a frustrating one. I have the dreaded P1751 ASR desired torque and no comm with the TCS. I must firstly say that I have done extensive searches including the extensive electrical sticky and have had no success. As far as I can ascertain the P1751 knocks out the TCS and ABS as these are both off line with the appropriate warning messages re 'active handling', service traction control, and service ABS.
Firstly let me tell you all what I have done to try and resolve this:
After reading Bill's informative posts (and others) on electrical problems I pulled all grounds apart, thoroughly cleaned and brushed them - found no signs of corrosion or damage. Next was the wheel sensors, harnesses (all female pins looked good and with good tension). Replaced the ETBCM module a couple of months ago so I'm hoping it hasn't gone for lunch. Anyway pulled the harness and checked all the pins for connection in fact have pulled most harness connectors I can find - all appear ok.
If I can tell you how the problem first started it may lead to a clue that I have missed. The car is mainly used for track days and after going through my previous set of Toyo RA1s, I decided to buy another set however the only sizing here in Aussie that was in the Proxes R888s (diff tread design to previos ones) that was close to fitting my aftermarket ZO6 rims was 255/40ZR17 front and 295/30ZR18 - now when I checked the outside OD the fronts were I mm taller than the rears. After taking the car for a run I had the following codes on the TCS module :
C1225, C1226 current codes both front wheel excessive speed variation
C1232, C1233, C1234 & C1235 H & C all wheel speed circuits shorted or open
C1255 H & C EBTCM internal malfunction ( not again )
Do you think the wheel sizing had anything to do with anything?
I've since put the original wagon wheels and tyres on and after clearing all codes I'm stuck with P1751 and No Comm on the TCS.
I'm not sure where to go next as Tech 2's with the corvette software are rare as rocking horse s##t here and there is no corvette 'stealerships' either.
I'm sorry about the length of the post but I am desperate - oh yeah the battery is new also.
I have the dreaded P1751 ASR desired torque and no comm with the TCS. I must firstly say that I have done extensive searches including the extensive electrical sticky and have had no success. As far as I can ascertain the P1751 knocks out the TCS and ABS as these are both off line with the appropriate warning messages re 'active handling', service traction control, and service ABS.Firstly let me tell you all what I have done to try and resolve this:
After reading Bill's informative posts (and others) on electrical problems I pulled all grounds apart, thoroughly cleaned and brushed them - found no signs of corrosion or damage. Next was the wheel sensors, harnesses (all female pins looked good and with good tension). Replaced the ETBCM module a couple of months ago so I'm hoping it hasn't gone for lunch. Anyway pulled the harness and checked all the pins for connection in fact have pulled most harness connectors I can find - all appear ok.
If I can tell you how the problem first started it may lead to a clue that I have missed. The car is mainly used for track days and after going through my previous set of Toyo RA1s, I decided to buy another set however the only sizing here in Aussie that was in the Proxes R888s (diff tread design to previos ones) that was close to fitting my aftermarket ZO6 rims was 255/40ZR17 front and 295/30ZR18 - now when I checked the outside OD the fronts were I mm taller than the rears. After taking the car for a run I had the following codes on the TCS module :
C1225, C1226 current codes both front wheel excessive speed variation
C1232, C1233, C1234 & C1235 H & C all wheel speed circuits shorted or open
C1255 H & C EBTCM internal malfunction ( not again
)Do you think the wheel sizing had anything to do with anything?
I've since put the original wagon wheels and tyres on and after clearing all codes I'm stuck with P1751 and No Comm on the TCS.
I'm not sure where to go next as Tech 2's with the corvette software are rare as rocking horse s##t here and there is no corvette 'stealerships' either.
I'm sorry about the length of the post but I am desperate - oh yeah the battery is new also.
Hi
Your quote "corvette software are rare as rocking horse s##t here " got my attention!!
That was funnyYou need to resolve the NO COMMS issue FIRST!There are TWO reasons for a NO COMMS issue.
1. There is a loss of power to the module. Recommend you check all the fuses to the module. I don't have access to my service manuals ( I'm at work
) or I would list the fuses to check. Do you have access to the service manuals? If so, check the fuses and then see if you have power at the connector.2. The serial buss wire is open or shorted. Do you have any other issues with any other modules on the car?? There are TWO small thin grey connectors to the left of the BCM. Those are the STAR Connectors and ALL the serial data wires terminate there. Examine those connectors and MAKE SURE that there clean and the tops are on tight. The top of the connector is a shorting bar that connects all the wires in that connector together. When I get home I will give you a schematic that will show you what each wire goes to so that you can read the EBTCM serial wire to ground and see if it is actually connected. You should be able to read that specific wire to ground and get a good resistance reading. If I remember correctly, I think I read something like 750 ohms but don't quote me on that one. If I have to I will pull mine apart and take a reading for you.
If any of the other modules are shorted to ground, it can and will effect all the other modules. Thats why I asked you if any other module is having issues. The door wiring harnesses are well known for effecting other modules. When mine shorted out the car wouldn't even start!
Just shaking the harnesses corrected that issue.Check that stuff out and get back to me. Are there any other DTC listed in the DIC? Recommend clearing everything and see what comes back.
I seriously doubt that your tires had anything to do with the issue. That cant cause a NO COMMS issue!
Figure out what is causing the NO COMMS issue and then we will go from there.Bill
Thread Starter
Heel & Toe
Joined: Nov 2006
Posts: 15
Likes: 0
From: Melbourne Victoria
Hi
Your quote "corvette software are rare as rocking horse s##t here " got my attention!! That was funny
You need to resolve the NO COMMS issue FIRST!There are TWO reasons for a NO COMMS issue.
1. There is a loss of power to the module. Recommend you check all the fuses to the module. I don't have access to my service manuals ( I'm at work ) or I would list the fuses to check. Do you have access to the service manuals? If so, check the fuses and then see if you have power at the connector.
2. The serial buss wire is open or shorted. Do you have any other issues with any other modules on the car?? There are TWO small thin grey connectors to the left of the BCM. Those are the STAR Connectors and ALL the serial data wires terminate there. Examine those connectors and MAKE SURE that there clean and the tops are on tight. The top of the connector is a shorting bar that connects all the wires in that connector together. When I get home I will give you a schematic that will show you what each wire goes to so that you can read the EBTCM serial wire to ground and see if it is actually connected. You should be able to read that specific wire to ground and get a good resistance reading. If I remember correctly, I think I read something like 750 ohms but don't quote me on that one. If I have to I will pull mine apart and take a reading for you.
If any of the other modules are shorted to ground, it can and will effect all the other modules. Thats why I asked you if any other module is having issues. The door wiring harnesses are well known for effecting other modules. When mine shorted out the car wouldn't even start! Just shaking the harnesses corrected that issue.
Check that stuff out and get back to me. Are there any other DTC listed in the DIC? Recommend clearing everything and see what comes back.
I seriously doubt that your tires had anything to do with the issue. That cant cause a NO COMMS issue! Figure out what is causing the NO COMMS issue and then we will go from there.
Bill
Your quote "corvette software are rare as rocking horse s##t here " got my attention!!
That was funnyYou need to resolve the NO COMMS issue FIRST!There are TWO reasons for a NO COMMS issue.
1. There is a loss of power to the module. Recommend you check all the fuses to the module. I don't have access to my service manuals ( I'm at work
) or I would list the fuses to check. Do you have access to the service manuals? If so, check the fuses and then see if you have power at the connector.2. The serial buss wire is open or shorted. Do you have any other issues with any other modules on the car?? There are TWO small thin grey connectors to the left of the BCM. Those are the STAR Connectors and ALL the serial data wires terminate there. Examine those connectors and MAKE SURE that there clean and the tops are on tight. The top of the connector is a shorting bar that connects all the wires in that connector together. When I get home I will give you a schematic that will show you what each wire goes to so that you can read the EBTCM serial wire to ground and see if it is actually connected. You should be able to read that specific wire to ground and get a good resistance reading. If I remember correctly, I think I read something like 750 ohms but don't quote me on that one. If I have to I will pull mine apart and take a reading for you.
If any of the other modules are shorted to ground, it can and will effect all the other modules. Thats why I asked you if any other module is having issues. The door wiring harnesses are well known for effecting other modules. When mine shorted out the car wouldn't even start!
Just shaking the harnesses corrected that issue.Check that stuff out and get back to me. Are there any other DTC listed in the DIC? Recommend clearing everything and see what comes back.
I seriously doubt that your tires had anything to do with the issue. That cant cause a NO COMMS issue!
Figure out what is causing the NO COMMS issue and then we will go from there.Bill
Thankyou for your time and interest. I'm not very savy with electrical so be gentle on me
I have checked all the fuses and they appear good. I rechecked the star connectors and the shorting bars and also appeared fine.I did have service manuals but they went missing when I had the car converted from left to righthand drive years ago. I have been working off photo copies of a 97 manual (I know - no active handling) but I was hoping most things were the same.
I'm not sure about testing for power to the EBTCB but will give it a go if you can teach an old dog new tricks. I do have a DMM so that's a start right.
No other codes except for P0101 as it has no MAF due to speed density tune or mafless tune and B0502 & B0507 B2482 as I pulled #2 fuse for DRLs - not required here.
Pro
Joined: Nov 2002
Posts: 717
Likes: 11
From: Pleasanton CA
Replace the ignition switch, that will probably solve most of your codes. Read Bill Curlee's post about the switch and how to fix it
Hi all, only my 2nd post but a frustrating one. I have the dreaded P1751 ASR desired torque and no comm with the TCS. I must firstly say that I have done extensive searches including the extensive electrical sticky and have had no success. As far as I can ascertain the P1751 knocks out the TCS and ABS as these are both off line with the appropriate warning messages re 'active handling', service traction control, and service ABS.
Firstly let me tell you all what I have done to try and resolve this:
After reading Bill's informative posts (and others) on electrical problems I pulled all grounds apart, thoroughly cleaned and brushed them - found no signs of corrosion or damage. Next was the wheel sensors, harnesses (all female pins looked good and with good tension). Replaced the ETBCM module a couple of months ago so I'm hoping it hasn't gone for lunch. Anyway pulled the harness and checked all the pins for connection in fact have pulled most harness connectors I can find - all appear ok.
If I can tell you how the problem first started it may lead to a clue that I have missed. The car is mainly used for track days and after going through my previous set of Toyo RA1s, I decided to buy another set however the only sizing here in Aussie that was in the Proxes R888s (diff tread design to previos ones) that was close to fitting my aftermarket ZO6 rims was 255/40ZR17 front and 295/30ZR18 - now when I checked the outside OD the fronts were I mm taller than the rears. After taking the car for a run I had the following codes on the TCS module :
C1225, C1226 current codes both front wheel excessive speed variation
C1232, C1233, C1234 & C1235 H & C all wheel speed circuits shorted or open
C1255 H & C EBTCM internal malfunction ( not again )
Do you think the wheel sizing had anything to do with anything?
I've since put the original wagon wheels and tyres on and after clearing all codes I'm stuck with P1751 and No Comm on the TCS.
I'm not sure where to go next as Tech 2's with the corvette software are rare as rocking horse s##t here and there is no corvette 'stealerships' either.
I'm sorry about the length of the post but I am desperate - oh yeah the battery is new also.
I have the dreaded P1751 ASR desired torque and no comm with the TCS. I must firstly say that I have done extensive searches including the extensive electrical sticky and have had no success. As far as I can ascertain the P1751 knocks out the TCS and ABS as these are both off line with the appropriate warning messages re 'active handling', service traction control, and service ABS.Firstly let me tell you all what I have done to try and resolve this:
After reading Bill's informative posts (and others) on electrical problems I pulled all grounds apart, thoroughly cleaned and brushed them - found no signs of corrosion or damage. Next was the wheel sensors, harnesses (all female pins looked good and with good tension). Replaced the ETBCM module a couple of months ago so I'm hoping it hasn't gone for lunch. Anyway pulled the harness and checked all the pins for connection in fact have pulled most harness connectors I can find - all appear ok.
If I can tell you how the problem first started it may lead to a clue that I have missed. The car is mainly used for track days and after going through my previous set of Toyo RA1s, I decided to buy another set however the only sizing here in Aussie that was in the Proxes R888s (diff tread design to previos ones) that was close to fitting my aftermarket ZO6 rims was 255/40ZR17 front and 295/30ZR18 - now when I checked the outside OD the fronts were I mm taller than the rears. After taking the car for a run I had the following codes on the TCS module :
C1225, C1226 current codes both front wheel excessive speed variation
C1232, C1233, C1234 & C1235 H & C all wheel speed circuits shorted or open
C1255 H & C EBTCM internal malfunction ( not again
)Do you think the wheel sizing had anything to do with anything?
I've since put the original wagon wheels and tyres on and after clearing all codes I'm stuck with P1751 and No Comm on the TCS.
I'm not sure where to go next as Tech 2's with the corvette software are rare as rocking horse s##t here and there is no corvette 'stealerships' either.
I'm sorry about the length of the post but I am desperate - oh yeah the battery is new also.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I got your E-mail with the picture of your meter. Your 97 manuals are VERY SIMULAR to the 97-99 C5 manuals. When I trouble shoot early C5's (97-98-99's) I use my 98 service manuals. I now have a DVD with all the manuals. If I find a schematic that you need,,Ill send it to you. Keep an eye on your e-mail for them.
I will look through the manuals tonight and come up with something.
Do you have a FRONT or REAR mounted EBTCM???
Thats important to know.
98's could have either front or rear mounted EBTCM. Hopefully yours is front mounted.
Bill
Your 97 manuals are VERY SIMULAR to the 97-99 C5 manuals. When I trouble shoot early C5's (97-98-99's) I use my 98 service manuals. I now have a DVD with all the manuals. If I find a schematic that you need,,Ill send it to you. Keep an eye on your e-mail for them.I will look through the manuals tonight and come up with something.
Do you have a FRONT or REAR mounted EBTCM???
Thats important to know.
98's could have either front or rear mounted EBTCM. Hopefully yours is front mounted.
Bill
Hi Bill,
Thankyou for your time and interest. I'm not very savy with electrical so be gentle on me I have checked all the fuses and they appear good. I rechecked the star connectors and the shorting bars and also appeared fine.
I did have service manuals but they went missing when I had the car converted from left to righthand drive years ago. I have been working off photo copies of a 97 manual (I know - no active handling) but I was hoping most things were the same.
I'm not sure about testing for power to the EBTCB but will give it a go if you can teach an old dog new tricks. I do have a DMM so that's a start right.
No other codes except for P0101 as it has no MAF due to speed density tune or mafless tune and B0502 & B0507 B2482 as I pulled #2 fuse for DRLs - not required here.
Thankyou for your time and interest. I'm not very savy with electrical so be gentle on me
I have checked all the fuses and they appear good. I rechecked the star connectors and the shorting bars and also appeared fine.I did have service manuals but they went missing when I had the car converted from left to righthand drive years ago. I have been working off photo copies of a 97 manual (I know - no active handling) but I was hoping most things were the same.
I'm not sure about testing for power to the EBTCB but will give it a go if you can teach an old dog new tricks. I do have a DMM so that's a start right.
No other codes except for P0101 as it has no MAF due to speed density tune or mafless tune and B0502 & B0507 B2482 as I pulled #2 fuse for DRLs - not required here.
Thread Starter
Heel & Toe
Joined: Nov 2006
Posts: 15
Likes: 0
From: Melbourne Victoria
I got your E-mail with the picture of your meter. Your 97 manuals are VERY SIMULAR to the 97-99 C5 manuals. When I trouble shoot early C5's (97-98-99's) I use my 98 service manuals. I now have a DVD with all the manuals. If I find a schematic that you need,,Ill send it to you. Keep an eye on your e-mail for them.
I will look through the manuals tonight and come up with something.
Do you have a FRONT or REAR mounted EBTCM???
Thats important to know.
98's could have either front or rear mounted EBTCM. Hopefully yours is front mounted.
Bill
Your 97 manuals are VERY SIMULAR to the 97-99 C5 manuals. When I trouble shoot early C5's (97-98-99's) I use my 98 service manuals. I now have a DVD with all the manuals. If I find a schematic that you need,,Ill send it to you. Keep an eye on your e-mail for them.I will look through the manuals tonight and come up with something.
Do you have a FRONT or REAR mounted EBTCM???
Thats important to know.
98's could have either front or rear mounted EBTCM. Hopefully yours is front mounted.
Bill
I have a front mounted EBTCM
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I sent you a BUNCH of schematics via E-Mail. Please let me know if you receive them and if there readable. Once you get them I will send you some specific pins to check.
Bill
Bill
Thread Starter
Heel & Toe
Joined: Nov 2006
Posts: 15
Likes: 0
From: Melbourne Victoria
have been away for a couple of days.....But thankyou for the schematics
- not sure where to test but followed the serial links and checked the resistance and all appeared to have no breaks or shorts I think. Still getting the no comm on the TCS and the P1571. Bob.
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