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Hi all. My 2000 c5 won’t start.
Ive checked all the threads on this forum and eliminated all the usual.
I have narrowed it down to the Tdr not actuating, however when I test it there’s power to the solid yellow when the ignition key is turned and constant live on the thick red but it seems that the black and yellow is not being actuated inside the bcm to allow it to start.
If I ground the black and yellow by bypass, the car then starts and the Tdr clicks but the car immediately stops again.
I have checked the clutch safety switch which is ok, and the Security light goes out. Obviously, the fact that the car starts eliminates the battery, solenoid, starter and ground terminals which have been cleaned and greased.
According to the diagram of the circuit everything seems to be working normally except the bcm starter enable relay control.
Question: is there anything else I can check before assuming it’s the bcm?
Tia Andy M
I don't know the exact ground point from where the BCM is provided a ground which it switches on to the yellow/black wire, maybe somebody here can provide that information. Have you tried disconnecting the battery for several minutes, if it's the BCM, doing this resets it. Hope this helps.
The body control module is grounding A9:C1 through splicepoint SP208 to the G104 in the engine room (below battery)
The splicepoint SP208 (shown in photo) is located above footwell (fusebox) on passenger side .
Another member of CF had problems with the TDR , the reason was a bad connection in the SP208 splicepoint. Due to this the BCM was not able to energize the TDR relay
Thanks for your information.
As I said, I have cleaned the ground points and checked all the usual things. I have not however checked your mentioned splice point.
I’m starting to think that either I scrap my nice condition c5 or I invest in a knock off Tech 2 but I see conflicting opinions on the subject.
Can anyone tell me definitively which version to buy, if there is additional software or Usb keys needed and do I need windows xp or can I use a mac. So confusing. Might be cheaper to scrap it, long term, as I don’t have easy access to parts here in UK.
Thanks for your information.
As I said, I have cleaned the ground points and checked all the usual things. I have not however checked your mentioned splice point.
I’m starting to think that either I scrap my nice condition c5 or I invest in a knock off Tech 2 but I see conflicting opinions on the subject.
Can anyone tell me definitively which version to buy, if there is additional software or Usb keys needed and do I need windows xp or can I use a mac. So confusing. Might be cheaper to scrap it, long term, as I don’t have easy access to parts here in UK.
I have both a Tech2 clone form China and a VCX NANO unit(also from china) and are running Tech2win software on my win 10 64 bit laptop .
The Tech2win has the same menues as the Tech2 clone , but you need to download and install some software from VXDIAG to install Tech2win on your laptop . Not hard to do . installation
I prefer running Tech 2 menues on a bigger laptop screen instead a smaller Tech2 scanner screen .
Tech2win is also cheaper than a Tech2clone
The ground is the C3 connector pin B7 on the BCM !!
Hi, I’ve watched your video on diagnosing the start and stop problem.
I tried removing both combs and spraying contact cleaner but they were very clean already. I don’t seem to have the module under the seat of my 2000.
My original problem was no start but while I was checking the fuses you mentioned, which I had already checked btw, I happened to remove fuse 25 while the ignition was on and when I replaced it the interior lights came on and I was able to open the windows.
I then found that the car would start but immediately stop as in your video.
I had previously checked the codes and the only current code was b2723 which is passkey I believe. If this is the case, surely the car wouldn’t crank at all.
Before I discovered that removing fuse 25 would reset the bcm there was no comms on bcm and rtd. After pulling the fuse and replacing I got the 2724 code so it was temporarily communicating but soon after stopped working again.
So, when I remove and replace fuse 25, while the ignition is on I can use the windows etc, so what can be causing this?
I’m on the verge of giving up on this car so I’m hoping you can help, as so far you seem to be my best hope.
Thanks.
Next time the car fails to crank have a helper hold the key in the start position while you use a broom handle with one end firmly on the starter case (NOT ON THE SOLENOID) and solidly hit the other end of the broom handle with a 3lb hammer. NO LOVE TAPS.... Solid blows to the end of the broom handle.
If the car immediately cranks the problem is the starter or more likely the solenoid. Solenoid on the C5 is WELL KNOWN for sticking....
Considering that you found that it started every time if you jumper the Red and Purple wires at the theft deterrent relay, I am skeptical that it is the starter solenoid.
If it starts every time when you jumper the relay, that would mean that everything downstream of the relay all the way to the starter solenoid should be okay.
I would try to diagnose the control circuits for the relay.
1.
When you jumpered the wires at the relay, did you confirm that the terminals of the relay actually make good contact? Poor pin fit will cause these kinds of problems, and jumpering the terminals just hides the pin fit issue. Check ALL 4 terminals, any one bad connection will cause everything to stop
2.
Use a DVOM to confirm that ground is present on the Yel/Blk wire, when you try to start it.
-Ground presence indicates the signal from the BCM is present to start the car
-No ground indicates either a circuit issue between the BCM and the terminal or the BCM does not want to provide ground because of some other fault.
3.
Use a DVOM to confirm B+ at the Yel wire (With the clutch depressed), when you try to start it
-B+ presence indicates the signal through the ignition switch, Crank fuse, and clutch pedal switch are all present.
-No B+ indicates an open somewhere in that circuit. Work backward from the relay terminal; check for B+ at both sides of the Clutch pedal switch and check its pin fit, check the pin fit of the crank fuse in the fuse block, check for B+ at the Yel wire (Pin B C1) and pin fit at the ignition switch itself (The switch, itself, can be the culprit as well).
Since many other functions seem to operate normal when the key is switched on, it's not likely that the circuit leading into the ignition switch would be the issue.
Originally Posted by Electron2002
Considering that you found that it started every time if you jumper the Red and Purple wires at the theft deterrent relay, I am skeptical that it is the starter solenoid.
If it starts every time when you jumper the relay, that would mean that everything downstream of the relay all the way to the starter solenoid should be okay.
I would try to diagnose the control circuits for the relay.
1.
When you jumpered the wires at the relay, did you confirm that the terminals of the relay actually make good contact? Poor pin fit will cause these kinds of problems, and jumpering the terminals just hides the pin fit issue. Check ALL 4 terminals, any one bad connection will cause everything to stop
2.
Use a DVOM to confirm that ground is present on the Yel/Blk wire, when you try to start it.
-Ground presence indicates the signal from the BCM is present to start the car
-No ground indicates either a circuit issue between the BCM and the terminal or the BCM does not want to provide ground because of some other fault.
3.
Use a DVOM to confirm B+ at the Yel wire (With the clutch depressed), when you try to start it
-B+ presence indicates the signal through the ignition switch, Crank fuse, and clutch pedal switch are all present.
-No B+ indicates an open somewhere in that circuit. Work backward from the relay terminal; check for B+ at both sides of the Clutch pedal switch and check its pin fit, check the pin fit of the crank fuse in the fuse block, check for B+ at the Yel wire (Pin B C1) and pin fit at the ignition switch itself (The switch, itself, can be the culprit as well).
Since many other functions seem to operate normal when the key is switched on, it's not likely that the circuit leading into the ignition switch would be the issue.
The Following User Says Thank You to Electron2002 For This Useful Post:
Hi, I’ve watched your video on diagnosing the start and stop problem.
I tried removing both combs and spraying contact cleaner but they were very clean already. I don’t seem to have the module under the seat of my 2000.
My original problem was no start but while I was checking the fuses you mentioned, which I had already checked btw, I happened to remove fuse 25 while the ignition was on and when I replaced it the interior lights came on and I was able to open the windows.
I then found that the car would start but immediately stop as in your video.
I had previously checked the codes and the only current code was b2723 which is passkey I believe. If this is the case, surely the car wouldn’t crank at all.
Before I discovered that removing fuse 25 would reset the bcm there was no comms on bcm and rtd. After pulling the fuse and replacing I got the 2724 code so it was temporarily communicating but soon after stopped working again.
So, when I remove and replace fuse 25, while the ignition is on I can use the windows etc, so what can be causing this?
I’m on the verge of giving up on this car so I’m hoping you can help, as so far you seem to be my best hope.
Thanks.
Removing the comb is a communication issue and probably not what you’re seeing…did you jump the red and purple wire at the TDR Relay ??….you probably just need a new relay…I don’t even think you looked at the relay yet…you did ground the circuit but if the relay is bad it’s still not going to work…if you can get the relay out we can show you how to test it to see if it’s operating correctly
Thanks for your reply.
It appears that the relay is doing it’s job, allowing it to start and then shutting off.
It’s the fact that the engine immediately cuts out I don’t understand.
I have not jumped the red to purple yet as I concluded, perhaps erroneously, that it was functioning correctly. I will however try the jumper method and then remove it, ready for your reply.
I tried pulling the combs, because in your video it enabled the car to continue running.
I’m starting to think perhaps the ignition assembly is contributing to the problem.
What of the B2723 code?
I frequently get the “pull the key and wait 10 seconds” message also.
Then there’s the fact that I have to pull fuse 25 in order to get the bcm to start the car and allow the normal functions. Albeit only temporarily. Could this be ignition lock related?
I tried using a new key that is unused but it still didn’t work.
Tia.
I hate being the bearer of bad news, but it maybe the BCM that needs replacing, many previous CF members have had this same problem, and removing and reinserting that fuse is one of the symptoms when the BCM fails. The BCM to PCM electrical handshake is not working causing the engine to cutt out after starting.
Thanks for replying,
Yes, I consider that a possibility also, as there was 7 historical codes for the bcm, but I think I should investigate the ignition circuit first, obviously, not having a proper manual makes it difficult to figure out how things work in relation to each other, but considering that the only current code was the B2723 code for Passkey I feel it warrants looking into first.
I’m going to try to get a manual!! Sod it!
Cheers Buddy.
This is the wiring diagram you had requested !!…when BCM grounds courtesy lamp relay the control side of relay 37 gets energized…you can jump terminals 87 and 30 at the relay to send that 12 volts to BCM !!
My suggestion is to perform a BCM relearn procedure it's here on this site. The relearn procedure makes the BCM accept the Ignition keys resistor pellet as the correct one. It also establishes the BCM to PCM handshake,if this handshake is not established the PCM will not provide outputs to the fuel injectors.
2000 c5 no start.
