Rick's Free Auto Repair Advice

Bypass PassLock Security System

Should you Bypass PassLock?

The GM PassLock system has a high failure rate which can leave you stranded. When the system fails, you have two options; fix it or bypass your PassLock Security System. Which is better? Well, here are my thoughts.

If you want to bypass PassLock

The fault in the PassLock system is almost always a bad sensor located in the lock cylinder case. When you insert the key and rotate the lock cylinder, a magnet passes by a sensor and the sensor sends a voltage to the body control module (BCM). The BCM has been programmed to expect a certain voltage. If it receives the expected voltage, it sends a start signal to the PCM.

When you bypass the passlock system you’re basically taking the lock cylinder case sensor out of the picture. You do this by inserting a resistor into the circuit that duplicates the voltage drop that would normally be caused by the lock cylinder case sensor.

What’s involved in a PassLock bypass?

You have to tear apart a portion of the dash if your lock cylinder is in the dash or a portion of the steering column if your lock is on the column. You locate a white blue wire and cut it. You go through a procedure with your DVOM to find the voltage that supposed to go to the BCM. You then install a resistor into the circuit that will duplicate the voltage to the BCM.

If you want to FIX the PassLock system

The fault is almost always in the lock cylinder case sensor or the wires from

bypass passlock

Lock cylinder case


the lock cylinder case to the BCM connector. The fix is to install a new lock cylinder.

PassLock bypass pros and cons

Pros: Cheap. You just need resistors

Cons: You lose all antitheft capabilities. Your car can be easily stolen now

It’s a lot of work. You still have to tear apart a portion of your dash. You have to know how to use a DVOM and splice in a resistor.

Still want to do this? Go to youtube and do a search for PassLock bypass.

PassLock repair pros and cons

Pros: You fix the problem and keep your car’s antitheft feature

Cons: Replacing the lock cylinder costs about $80. It’s a little more work than splicing in a resistor.

Rick’s advice on PassLock bypass

Personally, I think you’re crazy to bypass a PassLock system when you can fix it for about $80 and keep the anti-theft feature. Buy the darned lock cylinder case and follow the directions to reprogram. Geeze, how much easier can you get?

©, 2018 Rick Muscoplat

Posted on by Rick Muscoplat

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