UK 99 C5 Manual resto project

[teamzr1]

teamZR1 - am I recalling correctly that the infamous C5 steering column lock failure would, amongst other things, shut off the fuel pump?

I wonder what's the column lock status of Llewellyn's car? When my C5 failed GM's official dealer in UK was unable to get it going even after contact with GM HQ in the US. Eventually GM US said, "stick a column lock bypass on it and see if that works". The official dealer had no access to the unofficial part so I sourced one via Eurovettes in UK and it was fitted by the dealer. Problem fixed.

Being the fact that when he jumpers the relay then fuel pump is functional only directs to me than the wiring, pins, PCM output
CL would not prevent fuel pump being commanded
I see nothing in the wiring drawing of CL being involved with commanding fuel pumps on or off

I suggest he jumpers relay to get the engine running, which also then ups the voltage,
He could check if steering wheel is locked or not
Also, this would allow seeing if any other DTCs trip

As to CL, when I tune the PCM I turn off CL and also the limp mode when CL fails and any DTCs for CL so
no bypass module needs to be installed

 

[teamzr1]

teamZR1 - am I recalling correctly that the infamous C5 steering column lock failure would, amongst other things, shut off the fuel pump?

I wonder what's the column lock status of Llewellyn's car? When my C5 failed GM's official dealer in UK was unable to get it going even after contact with GM HQ in the US. Eventually GM US said, "stick a column lock bypass on it and see if that works". The official dealer had no access to the unofficial part so I sourced one via Eurovettes in UK and it was fitted by the dealer. Problem fixed.

If CL has failed it would trip DTCs then Llewelyn
should see and also on DIC would pop up "Service Column Lock"

If not seeing any of this and steering wheel is not locked then not an issue

DTC B2587 Column Lock/Unlock Drive A
DTC B2588 Column Lock/Unlock Drive A
DTC B2592 Column Lock/Unlock Drive B
DTC B2593 Column Lock/Unlock Drive B

 

[Yellowshark]

Just to add a point re Teams's post on WED at 17.22 where he says "The B2723 DTC is coming from the BCM and may have another VATs issue as that says the ign key pellet is not connecting with the contacts of the ign switch contacts for VATS". I had a similar problem a while back which the result included not being able to display the DIC and I did not have an OBD2 code reader. But I figured out that the BCM and PCM were having a problem whereby the PCM was not reading the ignition key code sent by the BCM. I did not know whether the problem was with the sensors in the ignition for reading the key, or whether it was further down the line. There is a great post on Corvette forum by a luminary, whose name I forget, covering fixing/restoring the plastic switching at the rear of the ignition switch assembley; which was beyond my rudimentary auto electrics capabiltiy. To cut a loong story really short, I bought a 2nd hand ignition key unit c/w ignition key and fitting that immediately fixed the problem; lol once I remembered to use the new ignition key!

 

[Yellowshark]

... Luminary was I think Bill Curley or something like that

 

[Custom exotics]

Maybe I am missing something but we had to change out the pcm on one of our c5s due to it not putting out a dwell cycle to the abs module we brought a second hand item in USA had boyd conningtons tunner program it for car plugged it straight in and started car straight up no issues no lights no fault codes and been perfect to this day prob some 15yrs later !!!

 

[V8 YEA]

My current car (99 FRC) would start for a second and stop, did the column lock bypass, fixed.
The one I mention way back in this thread had a bad ecu ( battery acid) that I swapped out for a flashed-to-VIN one from the States, car ran fine with the duff one but no speedo signal. The new one would turn the car over but not start,I spent HOURS in a freezing garage trying to the 10 minute thing, nothing worked until I had the ECU flashed on the car, took a few goes but eventually it the ecu took the full programme.
In short I think your new ecu needs reflashing, get a performance tune at the same time !
You can buy a flash online and download it yourself.

 

[Stingray]

CL would not prevent fuel pump being commanded
I see nothing in the wiring drawing of CL being involved with commanding fuel pumps on or off

While I recognise your knowledge of C5 is extensive I will mention again that the column lock system can interact with the fuel pump because it shuts off fuel if the car is driven above 2 mph with a fault. It seems to me that if it was feeling ornery it could conceivably be involving itself here, with or without the usual DIC message/code.

 

[Llewelyn]

My current car (99 FRC) would start for a second and stop, did the column lock bypass, fixed.
The one I mention way back in this thread had a bad ecu ( battery acid) that I swapped out for a flashed-to-VIN one from the States, car ran fine with the duff one but no speedo signal. The new one would turn the car over but not start,I spent HOURS in a freezing garage trying to the 10 minute thing, nothing worked until I had the ECU flashed on the car, took a few goes but eventually it the ecu took the full programme.
In short I think your new ecu needs reflashing, get a performance tune at the same time !
You can buy a flash online and download it yourself.

Thanks! You know I think you are seriously onto something there... I may get the ECU reflashed and give it a try. Know anywhere in the Midlands where I can get this done??

 

[V8 YEA]

I'm in Norfolk so sorry no, but to clarify, the chap who did mine downloaded my damaged ECU ON the car, I swapped the ECU's and he flashed the new one ON the car all via the OBD port. To get it flashed off the car I would think you would have to have a rig specifically for a GM ECU. That way all the wires are in the correct place to receive the correct signal. I'm no expert at all, I just spent a lot of time faffing about with that car's ECU set up and read a lot about it. I don't know if a Vauxhall dealer may have the gear for it as they sold C5's new and also Monaros which are Pontiac GTO's in the US. Cars of a similar vintage with LS1's in them. Or speak to a current Corvette/Camaro dealer. Ian Allen in Virginia Water ?

 

[Llewelyn]

I'm in Norfolk so sorry no, but to clarify, the chap who did mine downloaded my damaged ECU ON the car, I swapped the ECU's and he flashed the new one ON the car all via the OBD port. To get it flashed off the car I would think you would have to have a rig specifically for a GM ECU. That way all the wires are in the correct place to receive the correct signal. I'm no expert at all, I just spent a lot of time faffing about with that car's ECU set up and read a lot about it. I don't know if a Vauxhall dealer may have the gear for it as they sold C5's new and also Monaros which are Pontiac GTO's in the US. Cars of a similar vintage with LS1's in them. Or speak to a current Corvette/Camaro dealer. Ian Allen in Virginia Water ?

Thnanks for that - Makes sense... I'll have to have a look into it, I guess it depends on how damaged my ECU is but it's 100% worth a go. I bet it can be done with Tech II, I am tempted to invest in one as they seem pretty handy!

I am a bit poundstretcher by nature and want to try and avoid being stung with specialist pricing - I'd rather invest in the kit myself and use my own time working through the issues... Hopefully I will get it worked out soon, it can't be that complicated.

 

[V8 YEA]

Thnanks for that - Makes sense... I'll have to have a look into it, I guess it depends on how damaged my ECU is but it's 100% worth a go. I bet it can be done with Tech II, I am tempted to invest in one as they seem pretty handy!

I am a bit poundstretcher by nature and want to try and avoid being stung with specialist pricing - I'd rather invest in the kit myself and use my own time working through the issues... Hopefully I will get it worked out soon, it can't be that complicated.

Me too I'm from Yorkshire !

 

[teamzr1]

While I recognise your knowledge of C5 is extensive I will mention again that the column lock system can interact with the fuel pump because it shuts off fuel if the car is driven above 2 mph with a fault. It seems to me that if it was feeling ornery it could conceivably be involving itself here, with or without the usual DIC message/code.

As I mentioned, the PCM would not command fuel pump for CL issue
UNTIL the CL DTCs trip, only then would the PCM prevent car to be driven
PCM does not react to problems UNTIL DTCs trip

OP is not answering questions I ask him, simply when key on, engine off does the DIC say
"Service Steering Column Lock"
And is the steering wheel locked or NOT ?

Also, then if CL failed there would be the DTCs tripped, the OP has not answered if those DTCs tripped
We can stay trapped on the CL issue for years if the OP is not going to respond to this

OP has not also answered multi times asked to test the pin and wiring from PCM to the coil of the fuel relay
Until that is answered to know if PCM is commanding the coil or if the wiring is the case, we again cannot focus to the real problem and fix

GM did a TSB about this and did a software change in PCM to prevent CL issue
We could assume where the OP bought the new PCM that the vendor installed the newest GM software code segments and if so than the CL TSB fix is in it OR, that PCM seller did not.
I could answer that in 2 minutes IF knowing what the code segments are that could be obtained with a tuning tool

I solve this when tuning the PCM, I turn the SOB OFF, like I did here in a 1999 C5




When customers mail me their PCM, depending on the model of PCM I had to make up an off-board wiring jig like this for C5s


This allows me to fire up the PCM and flash changes to the GM code segments and the tune

If in OP testing that pin on PCM shows it is commanding the coil of fuel relay ON but does not show that with a multi meter
then clear in looking at their old PCM, that is not water damage, it is a F up by China that caused the side posts of battery to leak ACID
down to the whole area where the PCM is, along with the TAC (drive by wire) controller and the acid leaking into the wire loom and
F'ing up wires internally

Battery, a vendor in china wanting to make more profits stopped putting a flat washer on back side of battery post, that caused acid than to leak out

PCM, contact vendor where PCM was bought, require they state if the flash they put in has the GM CL TSB and if not correct, but OP has to ship that back to them here in USA

I mentioned contacting Keith of Eurosports, he now owns the PCM flash tool, he could not do off-board so would have to take vehicle to him and via him and me I would force flash PCM

Or OP buys a PCM flashing tool, and then I can make tuning changes along with custom performance tune all via email

 

[Llewelyn]

Sorry if I haven't been clear on some of the points - Let me clarify:

OP is not answering questions I ask him, simply when key on, engine off does the DIC say
"Service Steering Column Lock"
And is the steering wheel locked or NOT ?

Steering wheel NOT locked, no "service seteering column lock" alert - Car has an LMC5 column lock bypass kit fitted

OP has not also answered multi times asked to test the pin and wiring from PCM to the coil of the fuel relay
Until that is answered to know if PCM is commanding the coil or if the wiring is the case, we again cannot focus to the real problem and fix

Pin and wiring HAS been tested but only with the connector from the PCM disconnected. It bells out nicely with no intermittent connection. The wiring has not been checked by back probing the coil commanding wire (pin 9 PCM) with ignition on. So I have not verified 12v at that PCM connection.

View attachment 21081

Or OP buys a PCM flashing tool, and then I can make tuning changes along with custom performance tune all via email

I'd like to buy a PCM flashing tool and have access to this software - Where can I get it from?

 

[V8 YEA]

If I had that tool that enabled you turn off/on things on the PCM could I turn off the ABS, traction,active handling lights on the dash ?

That would be most helpful !

 

[V8 YEA]

I've been back through pistonheads gassing station and it was ten years ago when I did the ECU swap !
The guy who did it for me was Richard Ingram, his name on P/head is RINGRAM I'll attach the convo I had with him from that site.

C5 PCM / speedo malfunctioning - Page 1 - Corvettes - PistonHeads UK

www.pistonheads.com

 

[Llewelyn]

I've been back through pistonheads gassing station and it was ten years ago when I did the ECU swap !
The guy who did it for me was Richard Ingram, his name on P/head is RINGRAM I'll attach the convo I had with him from that site.

C5 PCM / speedo malfunctioning - Page 1 - Corvettes - PistonHeads UK

www.pistonheads.com

Thanks for the lead! I might drop him a message on PH... !

 

[teamzr1]

Sorry if I haven't been clear on some of the points - Let me clarify:

Steering wheel NOT locked, no "service seteering column lock" alert - Car has an LMC5 column lock bypass kit fitted

Pin and wiring HAS been tested but only with the connector from the PCM disconnected. It bells out nicely with no intermittent connection. The wiring has not been checked by back probing the coil commanding wire (pin 9 PCM) with ignition on. So I have not verified 12v at that PCM connection.

I'd like to buy a PCM flashing tool and have access to this software - Where can I get it from?

OK then, we have to assume that CL is not the issue

Simply using your meter with the relay out, the 2 pins of relay socket for the coil show 12 volts to coil when first turning key on ?
If you know the pin for ground, ohm'ed out fine.
And you state you ohm'ed out the wire from PCM to its pin of relay socket showed good
and if no 12 volts when key turn on (PCM will only command that 12 volts for a few seconds with a key on, engine off ) so have meter connected to the 2 relay pins before turning key on so need someone turning it on while you watch meter

Security light flashes when you open the door, that suggests VATS is not the issue

Have you checked as I mentioned there is a safety switch on clutch pedal, that prevents a start when clutch is not to the floor
You could check that and if need be jumper it and see if that is the issue

Jumper the 2 relay socket pins as you have done to start the engine, then using code reader, scanner or via diag of DIC go through all controllers
and write down all DTCs, if current or history to report back

You have no idea,
if the new PCM is not screwed up hardware wise, there are 2 fuses to 2 different 12 volts circuits, is PCM getting voltage to both circuits ?
No idea the vendor flashed in a good GM code segments and calibration, so we do not know quality of that PCM

Being acid damage, means male and female pins for PCM are not dirty, and when putting the connectors in did you look to see if all pins of PCM did not get pushed inward ( common problem) and all pins are clean ?

I asked about old PCM, is possible due to low or no voltage over time the PCM/BCM lost security code, and you changed it before learning about that relearn, is it possible as a test only to plug that back in and at least test try a start-up ?

 

[teamzr1]

If I had that tool that enabled you turn off/on things on the PCM could I turn off the ABS, traction,active handling lights on the dash ?

That would be most helpful !

Tuning tools are designed to only work for the PCM and TCM (auto tranny controller)

Tools such as GM's Tech-II is a tool that functions to other controllers
GM quit using that tool around 2013 model year vehicles, but you can find used ones on the internet or

China has cloned Tech-II and can be bought new for about half what GM tech-II costs

 

[Llewelyn]

Can I just say THANK YOU for all your efforts in hekping me here, it is much appreciated!! Great to have a knowledgeable guy on hand who is willing to help

Simply using your meter with the relay out, the 2 pins of relay socket for the coil show 12 volts to coil when first turning key on ?
If you know the pin for ground, ohm'ed out fine.
And you state you ohm'ed out the wire from PCM to its pin of relay socket showed good
and if no 12 volts when key turn on (PCM will only command that 12 volts for a few seconds with a key on, engine off ) so have meter connected to the 2 relay pins before turning key on so need someone turning it on while you watch meter

I do have a buddy with me who helps with the testing so I ask him to turn the key on/off etc when checking voltages. I never get any voltage to the relay coil, not for priming or running. Literally no 12v ever appears at that terminal

Security light flashes when you open the door, that suggests VATS is not the issue

Agreed

Have you checked as I mentioned there is a safety switch on clutch pedal, that prevents a start when clutch is not to the floor
You could check that and if need be jumper it and see if that is the issue

I haven't checked the clutch switch but it seems to operate okay by preventing cranking without the clutch depressed, I can bridge it out and try anyway though I guess, just to eliminate it as an issue!

Jumper the 2 relay socket pins as you have done to start the engine, then using code reader, scanner or via diag of DIC go through all controllers
and write down all DTCs, if current or history to report back

Excellent idea - I will do this when I am next with the car (most likely weekend)

You have no idea if the new PCM is not screwed up hardware wise, there are 2 fuses to 2 different 12 volts circuits, is PCM getting voltage to both circuits ?
No idea the vendor flashed in a good GM code segments and calibration, so we do not know quality of that PCM

I will double check but every fuse in both fuse panels inc. the maxifuses have all been continuity checked and seem to be ok

Being acid damage, means male and female pins for PCM are not dirty, and when putting the connectors in did you look to see if all pins of PCM did not get pushed inward ( common problem) and all pins are clean ?

All pins are clean and correctly seated, I didn't really show on camera but I spent a lot of time cleaning up those harness plugs and they are really in excellend order now given how bad they were. Pins PCM side are all looking straight and correct as well

I asked about old PCM, is possible due to low or no voltage over time the PCM/BCM lost security code, and you changed it before learning about that relearn, is it possible as a test only to plug that back in and at least test try a start-up ?

I think this is a great idea actually, I will try and do this now the PCM is fuly dried out. I can see a blown resistor on it but I reckon it's still worth a go for sure. I will do this and report back. I will also run a DIC code check as well and make a note of them...

 

[Llewelyn]

Tuning tools are designed to only work for the PCM and TCM (auto tranny controller)

Tools such as GM's Tech-II is a tool that functions to other controllers
GM quit using that tool around 2013 model year vehicles, but you can find used ones on the internet or

China has cloned Tech-II and can be bought new for about half what GM tech-II costs

I might look at a second hand Tech II, I've seen the Chinese ones which I am sure are fine but I'd prefer a genuine one if poss!