I have a 97 Olds Achieva with Passlock I. Car works fine and the cylinder is in good shape, except for the little resistance generator, stamped 'MEXICO'. I have read through this forum and it has been very informative on the resolution to my problem, namely to bypass the passlock. After finding out from the dealer it would be over $200 for a new lock cylinder (just the price of the part), I started researching this. I feel confident I could do this, however, I am unable to get valid resistance reading from the yellow and black pair. With the key off, I read 4.7K ohms and when on or started (runs for about 1 second), this is open, 95% of the time and 29.5K ohms, 5% of the time. When I do get a reading it starts at 29.5K and increases 200 ohms per second until the key is turned off. Can anyone tell me a valid resistance or a method for determining what my car needs?
I'm assuming you cut the yellow in half and you are reading resistance from the peeled back wire and the key side of your yellow wire. As for your question about the passlock, what do you need to try and do??? You said car works fine... is the security light on?
Craig...
Sorry if I wasn't clear. Yes, the security light is on and yes, I was reading the resistance from the yellow wire which is cut and testing from the key side. The car runs for a second or two before the passlock kicks in. Since the key cylinder itself is fine and only the passlock module that is embedded in the cylinder is bad, all I am trying to do is just bypass the passlock using a relay and a resistor. The diagram I am using is the permanent bypass from here:
https://12voltinstallations.8m.com/photo.html
Thanks for the reply!
If the passlock module portion of the key is bad then you can't determine what the correct resistance is. This is the part of the system that determines the resistance. The system only engages after you place the vehicle into the crank or start position. After that you can read the value. You must also reverse your meter's test leads. You will get two different values. take the average of the two. You probably should get the problem fixed as it could eventually strand you altogether.
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sparky
Since this is passlock I then you may have that little resistor pellet in your key that you can actually see? you can read a resisitance of that by using a multimeter to read the resistor value of the key itself.
Thanks for the reply, sparkie! But the car is already stranded in my driveway. This is why I am attempting to rid myself of a common GM problem without spending the common GM price to fix it. As I said the yellow and black lead are open 95% of the time, maybe I didn't specify that I cranked it. Thanks for bringing up the swapping of the leads, I was aware of it, but with an open reading, it was kinda pointless. I am sure the little mexican made resistance generator is at the heart of the issue (this is what the yellow/BLACK/ white wire connect to. This device was not intended to be replaced, as it is embedded into the lock cylinder. When the key is turned, it slides (a magnet?) across the inside of the generator and that is what triggers the generator. Before you crank the voltage (white wire) is 10.5 volts and after is 12 volts. I believe this is why you must crank the car. It would seem different voltages produce different resistances.
My understanding is that there are a number of valid resistance values the EMC will accept for the passlock. I have no problem disconnecting my battery to reset the ECM. This will allow me to force the ECM to relearn the passlock value. This will only work though, if I have a valid resistance for it to see. This is what I am attempting to discover.
I don't know if there are a diffent set for the different GM Makes or if it is different for each GM model, but I wanted to try spending $15 before I was forced to spend over $200. I parked it 5 weeks ago to replace the crankshaft sensor and change the oil. It hasn't moved since. Maybe I did something, or maybe it was a coincidence. Either way, it doesn't stay cranked.
tre3_1999 wrote:
Since this is passlock I then you may have that little resistor pellet in your key that you can actually see? you can read a resisitance of that by using a multimeter to read the resistor value of the key itself.
Your thinking of Passkey or Passlock III. These have the pellet in the key.