Passkey III Theft Deterrent Module Bypass – Full Guide

Passkey III Theft Deterrent Module Bypass – Full Guide

Your security system will have some theft prevention modules if you own a GM vehicle. These ensure that your car does not work in case of any robbery.

General Motors usually have three security systems. These include passkey II, pass lock, and Passkey III.

The key that works for the ignition helps you identify the theft-deterrent system. The passkey III uses the help of the body control unit to power the ignition.

How To Bypass Passkey III Theft Deterrent Module

The key contains a resistive chip that holds a particular value.

The body control unit has a program that recognizes this value.

If both of these values match, the control unit generates a signal in the form of code that ultimately kickstarts your vehicle.

The Requirement For Passkey III Theft Deterrent Module Bypass

In some cases, it becomes necessary for the owners to perform the passkey III theft deterrent module bypass.

Following are some conditions that might persuade you to conduct a passkey III theft deterrent module bypass.

  • Your vehicle randomly stops working.
  • The security light turns on.
  • Some days your vehicle works fine, and other days, it won’t start.
  • It starts for a few seconds and then stops functioning.
  • All main components of the engine are in optimal condition, but the ignition does not work.

Bypass Process

You must follow the steps for passkey III theft deterrent module bypass.

Measure The Resistance

To successfully perform the passkey III theft deterrent module bypass, you must calculate the resistance between specific wires.

There are two wires present in your lock cylinder: a yellow and a black one.

The yellow wire comes directly from the body control unit and ends in the ignition switch. In contrast, the black one holds the sensors.

It is necessary to measure the resistance between these wires through the ohmmeter. The sensor in the passkey system helps you to detect its value.

If it is not working correctly, you cannot find accurate measurements.

The resistance value will help you effectively carry out the passkey III theft deterrent module bypass.

Remove The Lock Cylinder

You will have to remove the lock system to access the security system. It will provide you the space to conduct the passkey III theft deterrent module bypass.

You can conduct it several ways; however, one of the most straightforward methods is using the key.

Insert the key into the ignition and put your car in accessory mode. Slightly press the key downward and pull the lock upward.

The lock cylinder will emerge out of the ignition. However, if these steps do not work, you will have to separate the steering wheel.

You must disconnect the battery and ensure no electric signals run through the car. Afterward, you will have to unscrew the steering wheel cover bolts.

Once you detach the covers, you can pull the steering wheel and view the lock cylinder.

The process also requires you to disconnect certain switches, such as the ones attached to the horn, wipers, and indicators.

They might become accidentally activated if they remain connected.

Connect The Resistor

The value of resistance on the meter helps you find the resistor of the exact measurement. If the numbers are around 500 or 520, you should get a resistor of 500 ohms.

You can easily find the two wires in the lock cylinder. You do not have to cut or detach them.

Only remove the insulation to connect these wires efficiently.

Connect the yellow wire with the resistor and then attach the black wire. It allows you to reprogram your ignition system’s signals to the body control unit.

Passkey III Theft Deterrent Module Bypass

As a result, you will be successful in passkey III theft deterrent module bypass. Once you attach the resistor, you must wait for 10 to 15 minutes.

The entire system requires some time to shift the point of signal origination.

Now the resistor is responsible for generating the code that allows the body control to transmit the signal wave. It passes the theft-deterrent system and ignites the engine.

Once the passkey III theft deterrent module bypass is done, you can again check the resistance value through the ohmmeter.

If there is a number, it is another sign that you have efficiently completed the passkey III theft deterrent module bypass.


Following are some necessary items that you will need to perform the passkey III theft deterrent module bypass.

These will cost you less than $100, and you can find them in the local stores.


You will need these to detach the bolts that hold the steering wheel.

Ohm Meter

Use a functional ohm meter with a large reading scale. It will allow you to measure the resistance and proceed further.

Wire Strippers

These will help remove insulation from the wire and provide you the space to attach the resistor between them.


An electronic component allows the current flow between the wires and the body control unit.

It transmits the electrical signal to the engine unit, enabling the vehicle to function with passkey III theft deterrent bypass.

Factors To Consider

It would be best to consider the following factors before carrying out the passkey III theft deterrent module bypass.

The Necessity Of Theft Deterrent Modules

As the name suggests, these systems prevent your car from being stolen. Therefore ideally, it is an intelligent decision if you keep them in your vehicle.

Relearning Keys

Relearn is the condition where you provide the body control unit with another unique code. It differs from the one associated with your previous key.

Therefore, it is a passkey III theft deterrent module bypassing the current security setting. It happens when you lose your standard key.

As a result, you attempt to kickstart your vehicle through a master or duplicate key.

However, your vehicle does not function because the system cannot detect the code from this new key. The process also removes codes from the former keys.

You have to insert this key into the ignition during the accessory mode.

You must turn the car on and off several times while waiting for 5 or 10 minutes during each attempt.

You may also notice the security light beaming through this procedure.

However, your theft deterrent module will activate on this key after repeatedly turning the switch on and off.

Keeping The Wires Intact

While performing the passkey III theft deterrent module bypass, you do not have to strip the two wires. These are necessary to build the connection with the resistor.

Cutting them off can detach them from the control unit and destroy the theft-deterrent system.

As a result, your vehicle will not start, and you will have to opt for technical help.


The passkey III theft deterrent module bypass is quite a simple task. You can succeed if you possess the required instruments and insights to tackle your vehicle.

You must be sure of the measures you have to employ to remove the lock cylinder.

It is the only way to access the central system that holds the sensors for the module. In most cases, professionals may demand quite hefty amounts.

Therefore, it is more suitable for you to educate yourself and gain the ability to solve the issue.