97 Lumina, Randomly wont crank,

[wcshort]

I'm not too worried about cranking the car while in gear. I am the only driver of the car and you must have the car in park to remove the key.

How can I bypass it, at least temporally?

[wcshort]

Okay, so I got to the Theft deterrent relay. Here is my plan...

Buy a new relay ($16), install it and hope for the best.
BUT...
if the problem persists the cause is most likely the Theft Deterrent Module ($200+, dealer part) and I don't feel that the module is worth it's own weight. If someone wants to hotwire my car I honestly feel sorry for them. Instead of a $200+ replacement I would just wire in a switched jumper that would allow me to flip a toggle switch to bypass the relay, start the car then switch it back on to restore the PNS switch and starter relay fuse.

Anyone see any flaws? I know it's not the proper solution and not the safest one, but at this point financially it is the only one I have.

[Tech II]

If the problem is the theft deterrant module, it might not ground the relay, and in addition, it might to be sending a fuel enable signal to the PCM.....

Try the new relay.....

[wcshort]

New relay is in. Time to wait.

Tech II, Do you have a wiring diagram that shows the workings of the theft deterrent module? or something that shows the fuel enable relay system?

[Tech II]

No, it's a black box......the only schematics to it are inputs and outputs,,,,if the module is bad, it does mainly three things: controls Theft/Security light, grounds relay for starter, and sends a fuel enable signal to the PCM(this is a generated signal, not an on/off input....you can't create this signal)....

[wcshort]

Well, Bad news. The new relay did not solve the problem.

Would a bypass of the relay work? or would the module still ground out the starter?

I'm really not happy at GM right now, not at all.

Any suggestions for my next move? Thanks for all your help so far, I do appreciate it very much.

[aleekat]

I haven't seen any testing of voltage drop across the battery cables. They may look good at the ends, but inside the sheathing, corrosion. I've had 3 vehicles with the same symptoms. Very intermittent. Replacing both cables fixed them.

[wcshort]

Which cables should I test? Where and how? I'm assuming checking the positive battery terminal to the ground and starter positive cable (big one) to ground. Would this be a consistent volt drop or would it only happen when I have the problem?

[wcshort]

Update: bypassing the theft deterrent relay did not solve the problem or allow the car to start.

Also. If it were a bettery cable problem shouldn't my solenoid still click as it takes only minimal power to actuate?

[Tech II]

GMtech1 gave you the schematic....I told you in post #27 what to check....

[wcshort]

From post 27...

Have you tried another relay?

Yep, Replaced it.

If no, remove relay and attach a test light to terminals C2 and A1......turn key to crank.....does it light? If no, check for power on yellow wire(C2) with key in crank position.....if ok, then theft module or wire to it is problem....

If yes, install a jumper from A2 to C1......turn key to crank.....does engine crank over?

If yes, you need relay.....if no, check for power on yellow wire(A2) with key in crank position.....if ok, check circuit #6, especially terminal B3 in connector C100.....

The problem is that often the no-start problem will fix itself within a short time. A few times it has taken a couple days. If I get all the way to the relay and try to check the terminals there is a strong chance that the problem will disappear before I can get to it, but I will try.

The connector looks like this.

If the problem is the TDM what are my options?
I have looked around and found a complete bypass system for $180 here , any thoughts?

Thanks for the help.

[autojoe]

like tech 2 says passkey 2 system,I have seen bad contact issues causing intermittent starting problems with a faulty starter enable relay.

[wcshort]

Anyone know where to find connector C100?

[gmtech1]

C100 is the "pass-thru" connector at the right side of the firewall. Where the harness "passes thru" the firewall to the passenger compartment.

[gmtech1]