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Hello all. I seem to have a pretty unique problem I believe.
My car is a 2001 z06
This spring I had a hard time getting it out, so the following parts have 1285 miles on them.
Ac delco ignition switch
Optima red top battery
Lmc5 module
I went through and found multiple loose grounds and a few poor splices for a scavenge pump and air fuel gauges. All these are soldered abd heat shrink tubing now.
This spring the car would always turn over but never fire and stay running.
The new problem is the car will act dead. I open the door and the lights come on just fine. Key fob works, door locks etc. Key in the gauges sweep, fuel pump primes and then I turn it to start and I hear a click in the passenger foot well and that is it.
Dead battery? Hooked to a charger makes no difference and hooked to my buddy's diesel truck no difference.
So I look into schematics and jumper the clutch pedal sensor. No difference
Ohm test the clutch switch and it looks good. At this point thinking starter.
Next I decided jumper the red and purple wires of the TDR. Car starts everytime like nothing.
So now I believe the starter, battery, solenoid is fine and I buy a replacement relay. No luck.
So there are two yellow wires, one has a black stripe on it. One is the clutch and the other I believe is theft deterrent or something like that in the bcm.
The only other issues with the car are the HVAC backlight goes dim. Easy fix I think
Cracked rear rim that someone tried to repair once
Also now I am noticing that my seat isn't moving when I put the key in and take it out. Help? Possibly?
Took it to the gas station and it started with the key to leave there but then after lunch with the gf's parents it needed to be started under the dash again. One thing to note is I can start it under the dash and then shut it off, and the car will not restart with the key. Needs to be done under the dash again.
Also I am now seeing service column lock on the dash.
This all makes me suspect the BCM, which I had as a prime suspect earlier this year.
When the car fails to crank, what is happening to the SECURITY light on the dash when the key is left in the ON Position?
Security light is:
OUT?
Flashes??
R
ON Solid???
When the key is returned from the start position back to the on position, the security light as well as a few other of the dash lights comes on and then goes out right away
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....
I would venture to guess it is your starter solenoid also.............I had your same issues and when I replaced my starter they all went away. My starter replacement bill installed was roughly $300.00. 8VETTE7 and BILL CURLEE are legends in here listen to their suggestions.
I would venture to guess it is your starter solenoid also.............I had your same issues and when I replaced my starter they all went away. My starter replacement bill installed was roughly $300.00. 8VETTE7 and BILL CURLEE are legends in here listen to their suggestions.
Ok I will try that when I get home. I have read many threads with Bill in them and I know he is good.
One quick thing, when I turn the key to start I should see 12+ volts on the purple wire from the TDR correct?
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.
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.
Alright, I put my meter on the yellow black wire and had my brother attempt to start and the car just started up. So I am not sure what that means but he had to go and I didn't have a chance to do much more troubleshooting.
So I guess not much to report
Not enough hours in the day it would seem.
When things are intermittent, it really makes these things difficult.
One other thing I might suggest doing, the next time you start diagnosis again. Simply put a finger on the relay, while someone tries to start the car and see if you can feel it click. There are other relays in the fuse block that may also click at that time, so sound alone is not a good indicator. A tactile check can be helpful to confirm the very basic function of the relay switching on.
If it doesn't click, then we know something wrong on the control side of the relay.
Last edited by Electron2002; Sep 15, 2016 at 11:26 AM.
When things are intermittent, it really makes these things difficult.
One other thing I might suggest doing, the next time you start diagnosis again. Simply put a finger on the relay, while someone tries to start the car and see if you can feel it click. There are other relays in the fuse block that may also click at that time, so sound alone is not a good indicator. A tactile check can be helpful to confirm the very basic function of the relay switching on.
If it doesn't click, then we know something wrong on the control side of the relay.
Right now the way I start the car is by popping the plastic cover off the relay and then pressing the armature so the contacts touch. So maybe just pull the cover off and watch?
Usually there isn't much gap between the contacts, so I'm not really sure how easy it will be to see them close. But that is a possibility.
If you find that the B+ or ground isn't present on the yel or yel/blk wires respectively. Then just follow the diag flow I already described. The repair will vary depending on what you find.
For example: if you find that ground isn't present on the yel/blk wire, then you need to check that circuit. Since that wire only goes directly to the BCM, you should check pin fit of the wire to the bcm and if that is okay, then it means the BCM may not be providing the signal. That could mean a problem with the BCM or it could mean that all the conditions aren't being met for it to provide ground.
Just have Ave. to do the ground work to figure out which path you need to pursue
Originally Posted by 11ellswray
Let's say there is something wrong upstream from the relay. Then what is the next step?
So after I ran out of options i took the car to Schelen Gray in St.Paul, Minnesota.
They said the car had high resistance on the grounding circuit. They gave me two options, pay them per hour to find the problem and repair it or pay a fixed rate and they put their own grounds in. Afterward I looked under the hood at the old grounds and see no change but that is another discussion. So after completing that task i get a phone call that, now the grounds are good but the problem still remains.
From what the guy can tell is, the BCM is not getting a signal from the key that i am asking it to start.
Next day I am called and told there was something wrong with the wiring between the key and the BCM. I send my brother Ryan to pick the car up, with $960 and now it starts everytime with the key.
However, now i have a P0102 C accompanied by the CEL.
So I search around, while i go to look at the plug, multimeter in hand, trying to see if the sensor isnt getting a good ground I find the red wire and the yellow wire are almost cut through. Thinking I found the culprit to the problem I solder them back together, heat up the shrink tube, and fire it up. Code comes back immediately after I clear it.
Now i bust out the scan tool, live data show the MAF is reading a constant 19LBs/MIN.
Completely constant, no movement what so ever. The scan tool will even plot it out on a graph and it stays perfectly still regardless of throttle position or RPM. So one problem solved, on to the next. Also sounds like my AC compressor is squealing and I have a 0645 code that seems to confirm that as well.
Odd starting issue please help.
Great advice!
