99 vette no crank many codes
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Never heard a BCM relay click, they are really small. Are you sure it is not a relay in the fuse box or that area?
You say the BCM clicks with the ignition switch OFF. Does the key have to be in the ignition for this to happen?
Does the Security light go OFF when you insert the key?
Does it crank, but not start/run?
If you want to jumper around the VATS/BCM to crank and run the car you can do it with one wire. Let me know if you have questions.
MUST HAVE AN AUTO IN PARK/NEUTRAL OR MANUAL IN NEUTRAL!!!!!!!!!!!!!!!
Here is a way to jumper the car to start and drive. PLEASE MAKE SURE THE CAR IS IN PARK OR NEUTRAL WHEN YOU DO THIS. Go to Post 66 and read about jumpering the Theft Deterrent Relay.
The jumper is just used to get the starter going to fire up the engine. Remove it as soon as it fires since the starter is engaged when the jumper is in place.
You can test it first with the ignition OFF to see how it gets the starter turning. Then with the key in ON you can crank and start the car and drive off.
I know several people that have used this and it worked perfectly.
http://forums.corvetteforum.com/c5-t...ipc-out-4.html
You say the BCM clicks with the ignition switch OFF. Does the key have to be in the ignition for this to happen?
Does the Security light go OFF when you insert the key?
Does it crank, but not start/run?
If you want to jumper around the VATS/BCM to crank and run the car you can do it with one wire. Let me know if you have questions.
MUST HAVE AN AUTO IN PARK/NEUTRAL OR MANUAL IN NEUTRAL!!!!!!!!!!!!!!!
Here is a way to jumper the car to start and drive. PLEASE MAKE SURE THE CAR IS IN PARK OR NEUTRAL WHEN YOU DO THIS. Go to Post 66 and read about jumpering the Theft Deterrent Relay.
The jumper is just used to get the starter going to fire up the engine. Remove it as soon as it fires since the starter is engaged when the jumper is in place.
You can test it first with the ignition OFF to see how it gets the starter turning. Then with the key in ON you can crank and start the car and drive off.
I know several people that have used this and it worked perfectly.
http://forums.corvetteforum.com/c5-t...ipc-out-4.html
Thread Starter
Racer
Joined: Jul 2005
Posts: 381
Likes: 0
From: bluff city tn.
it is the bcm clicking not relays in fuse box you can not comm. with bcm or pcm the bcm is the power mode master so I think it is bad and car will not crank but some times it will try to crank starter just clicks like a low battery but battery has 12.5 volts all kind of messages come on in dic like reduced power service traction service abs fuel pump doed prime when key turned on
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
I will assume that the BCM clicking relays is probably low voltage into the BCM. May not be a bad BCM. Low voltage on a relay coil will cause it to click. Could also be a bad BCM ground.
BCM +12V power feeds from I/P fuse box:
Fuse #25 = BCM Logic Power Feed (Powered all the time)
Fuse #23 +Power feed for 12V BCM Drive outputs (CL)
Fuse #13 = 12V switched from ignition switch (ON, and START positions)
Fuse #9 = 12V from Ignition switch (ON and ACC position)
BCM grounds:
A9-C1 connector pin Logic Ground
A2-C3 Power Drive Ground
G104 & G202
It is not uncommon for the electrical contacts in the ignition switch to burn and cause low voltage even though the battery is good.
I would check first for low voltage using the info above. Let me know if you have any questions.
BCM +12V power feeds from I/P fuse box:
Fuse #25 = BCM Logic Power Feed (Powered all the time)
Fuse #23 +Power feed for 12V BCM Drive outputs (CL)
Fuse #13 = 12V switched from ignition switch (ON, and START positions)
Fuse #9 = 12V from Ignition switch (ON and ACC position)
BCM grounds:
A9-C1 connector pin Logic Ground
A2-C3 Power Drive Ground
G104 & G202
It is not uncommon for the electrical contacts in the ignition switch to burn and cause low voltage even though the battery is good.
I would check first for low voltage using the info above. Let me know if you have any questions.
Thread Starter
Racer
Joined: Jul 2005
Posts: 381
Likes: 0
From: bluff city tn.
i have already checked voltage and ground all are ok voltage is around 12.4 to 12.6 same at battery grounds checked good after I cleaned ground thought the ground would fix my problem but it did not I am going to check data lines next because I can not comm with bcm or pcm
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Need some clarification, if you can't comm with the BCM, how do you get that indication from the IPC display?
You will need the connector pinouts to check out the serial bus. If you don't have an FSM let me know.
I would like to know what happens if you try the jumpering I described above.
BCM relays clicking should mean a low voltage issue from power in or on the ground side.
Could be a connector pin not seated. It happens.
At some point we probably need to start talking on the phone. You can PM me anytime. Mr. Sam
You will need the connector pinouts to check out the serial bus. If you don't have an FSM let me know.
I would like to know what happens if you try the jumpering I described above.
BCM relays clicking should mean a low voltage issue from power in or on the ground side.
Could be a connector pin not seated. It happens.
At some point we probably need to start talking on the phone. You can PM me anytime. Mr. Sam
Thread Starter
Racer
Joined: Jul 2005
Posts: 381
Likes: 0
From: bluff city tn.
the car is not at my house i am busy this time of year our son races mx i have been thinking on this car a lot and i took out the ignition switch i am going to take it apart tomorrow at work and look at it did not get to check data lines like i wanted to tech 2 was tied up at work when i left today i just want to be sure what problem is before we replace anything i am hoping switch just don't under stand why i have all the correct voltage at bcm connector
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Thread Starter
Racer
Joined: Jul 2005
Posts: 381
Likes: 0
From: bluff city tn.
got to work on car again got a used bcm fixed the problem I should have just put one in along time ago just wanted to make sure that was it before buying one thanks for all the help