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Wicked Wrench
Wicked Wrench, Master ASE/GM Tech 25 Years
Category: Chevy
Satisfied Customers: 460
Experience:  Master ASE/ GM Tech 25 years with GM
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1996 camaro: alarm light..guages blinking

Customer Question

my 1996 camaro 3.8L, passive alarm system has disabled the engine to crank over. The security light on the guages blinking on and off. I have a spare key, but how do i attempt to reset this problem? The engine will not crank!
Submitted: 7 years ago.
Category: Chevy
Expert:  Wicked Wrench replied 7 years ago.
In order to reset, you should have a good understanding as to how it works. I will paste a series of documents which you should copy & save to your computer for future referance, & repair. You're probably going to have to replace the Ignition Switch Assembly as well.

Let me know if you get stuck...

General Description

The personal automotive security system (PASS-Key II) is standard equipment on this vehicle. The system is designed to prevent vehicle theft by disabling the engine unless an ignition key assembly with a specific electrical resistance is used in the ignition cylinder assembly. The components of the system are the ignition key assembly, the ignition cylinder assembly, the theft deterrent module assembly, the theft deterrent relay assembly, and the powertrain control module (PCM).

System Operation
The PASS-Key II system is designed to prevent the engine from starting if the proper resistance is not sensed from the ignition key. Of the 15 key codes (resistance values) available, only one will work with each BCM. Once the key code is programmed into the BCM, the resistance value is stored in a non-volatile memory.

The PASS-Key II system prevents the engine from stating by controlling the theft deterrent relay and the PCM fuel enable input. If the PCM does not sense the proper frequency signal on the fuel enable input, it will not provide fuel to the engine.

If the wrong resistance value is sensed when the ignition switch is in the "RUN" position, the BCM will not ground the starter enable circuit and will not output the fuel enable signal for approximately three minutes. This prevents the engine from starting and discourages the thief from trying key codes (resistance values) at random.

If the correct resistance value is sensed when the ignition switch is in the "RUN" position, the BCM will ground the starter enable circuit and output the fuel enable signal. This will allow the engine to start normally.

If the PASS-Key II system detects an open or short to ground when the ignition switch is in "RUN" position, the BCM will default to fail enable. Fail enable occurs when the proper key resistance has been sensed before the open or short to ground occurs. Fail enable will illuminate the security indicator lamp and allow the operator to stop and start the vehicle until the problem is corrected.

Ignition Key

PASS-Key II System Components (Typical)

The ignition key for vehicles equipped with the PASS-Key II system is an assembly of a typical square ignition key blank and resistor. The ignition key blank and resistor are not serviceable separately. There are 15 different resistance values. The ignition key also has mechanical cuts similar to non-PASS-Key II ignition keys.


  • When servicing the PASS-Key II system, obtain all ignition keys, if possible, and verify proper values with J 35628-A, VATS/PASS Interrogator.

Steering Column Lock and Ignition Cylinder

Ignition Cylinder Wire Routing

The ignition cylinder in vehicles equipped with the PASS-Key II system contains a set of electrical contacts used to measure the resistor in the ignition key. When servicing the ignition cylinder, be certain to maintain proper wire routing. A two pin connector at the base of the steering column connects the contacts to the vehicle wiring. The connector is also used for diagnostic purposes. The ignition cylinder also performs all functions of ignition cylinders on non-PASS-Key II vehicles. When replacing an ignition cylinder, it will he necessary to make new ignition keys which match the PASS-Key II key code of the BCM and the mechanical cut of the new ignition cylinder.


  • The wire routing for the contacts inside the steering column is critical.


Body Control Module

The BCM contains the logic of the PASS-Key II system. The BCM has inputs from the battery, ignition circuits, key resistor, shock sensor, and door lock, door jamb and hatch switches. The BCM has outputs to the starter enable circuit, the fuel enable circuit, the security lamp circuit, and the remote hatch release. The BCM also controls power locks, interior lamps, horn chirps and parking lamp flashes for locking and arming functions.

The BCM has some diagnostic features, including diagnostic trouble codes.


Ignition Input
The ignition input is used to turn the BCM on. When the BCM is turned on, it will read the resistor and control the outputs accordingly. When the BCM is turned off the resistor is not read, and the theft deterrent relay and fuel enable output will not allow the engine to start. When the ignition switch is in the 'OFF" position, the battery input to the BCM will draw about 75 milli-amps for the first 10 minutes and about 2.4 milli-amps after 10 minutes of ignition off.

Key Resistor Inputs
The key resistor inputs are used to determine if the correct ignition key is being used to start the vehicle. The key resistor inputs are read when the ignition is turned on. If the key code (resistance value) of the ignition key matches the value stored in the BCM, the theft deterrent relay and fuel enable output will allow the vehicle to start. If the resistance value of the ignition key does not match the value stored in the BCM, the relay and fuel enable output will not allow the vehicle to start.

Starter Enable Output
The starter enable circuit controls the theft deterrent relay. When the BCM sees the proper resistance at the ignition key, it grounds the starter enable circuit which allows the engine to he cranked. If the BCM does not sense the proper resistance at the ignition key, it will not ground the starter enable circuit.

Fuel Enable Output

The fuel enable circuit is an output from the BCM and an input to the PCM. When the BCM senses the proper resistance at the ignition key, it will output a signal to the PCM. If the BCM does not see the proper resistance at the ignition key, it will not output the signal to the PCM.


Security Indicator Lamp Output
The "SECURITY" lamp circuit is an indicator lamp output. The lamp output will be grounded during a 5 second "bulb test" at key on, at any time that the BCM is preventing the engine from starting, during an open or short to ground, or if the BCM is not properly programmed.

Theft Deterrent Relay
The relay is used to stop the engine from cranking if the correct resistance is not sensed at the ignition key. It prevents the engine from cranking by opening the circuit to the starter solenoid switch.

Powertrain Control Module
The PCM reads the fuel enable circuit to determine if fuel injection should be allowed. If the fuel enable signal is not present, the PCM will not allow fuel injection. If the signal is present, the PCM will allow fuel injection and normal engine operation.

The PCM has some diagnostic features associated with the fuel enable input, including diagnostic trouble codes.

Circuit Operation
PASS-Key-II is a theft deterrent system which prevents the vehicle from starting if the Ignition Key "Resistance Code" is not recognized by the Body Control Module. If the Resistance Code is not recognized, the Engine is prevented from starting in two ways: battery voltage from the Ignition Switch to the starter is disabled by a Theft Deterrent Relay and fuel to the fuel injectors is stopped without the presence of a fuel enable signal. Also, if the vehicle is equipped with the Universal Theft Deterrent System (UA6), an unrecognized "Resistance Code" will trigger an audible alarm cycle.

Resistor sensing contacts are located in the Ignition Key Lock Cylinder. These contact the Key Resistor Pellet on the key when it is inserted. When the lock is rotated, Ignition voltage is applied to the Body Control Module and pellet resistance is read at this time. The Pellet resistance is read across connector C3 terminals "C2" and "D7" which is then compared against the resistance value stored in the module. If the Key Resistance Pellet is the proper resistance, connector C3 terminal "C11" is grounded, energizing the Theft Deterrent Relay. At the same time, a signal is applied at connector C3 terminal "D8" to enable the Powertrain Control Module (PCM). When this signal is received by the PCM, it allows fuel injector pulses to begin. If the Key Resistor Pellet is the wrong value, the Body Control Module will shut down for 3 minutes + or 18 seconds. During this interval, there will be no output at connector C3 terminals "C11" or "D8" and the "SECURITY" Indicator will illuminate. The Ignition Switch input is ignored during this shut down period. For this reason, the timer will run and the "SECURITY" Indicator will remain illuminated with Ignition on or off. Once the timer has completed its 3 minute + or - 18 second shut down, the next time Ignition is cycled from off to on, the Body Control Module timer is reset. A key having the correct code can then be used to start the Engine.

Security Indicator Operation

The "SECURITY" Indicator is controlled directly by the Body Control Module. The following describes the modes of indicator operation:

  1. When the Ignition is put in "RUN," "BULB TEST," or START," the "SECURITY" Indicator illuminates for about 5 seconds as a bulb check.
  2. If the Body Control Module is actively in the shut down mode and thus preventing the vehicle from starting, the indicator will be illuminated (grounded) by the Body Control Module for 3 minutes + or 18 seconds after Ignition is turned on.
  3. If the resistor sensing contacts or CKTs 1073 or 1074 are open or shorted, or if a defective key is being used at the time Ignition is turned on, the "SECURITY" Indicator will flash at a rate of once per second and the Engine will not start; however, the 3 minute + or - 18 second lockout will not he activated. Additionally, if an unprogrammed module is present and there is an open or short, or if a defective key is being used the Body Control Module will not program a key code, the "SECURITY" Indicator will flash at a rate of once per second, and the Engine will start.
  4. Lock Cylinder CKTs 1073 and 1074 are continuously monitored and if a fault is detected in these circuits for 1 minute, the indicator will turn "ON." If the fault condition goes away for 1 minute the indicator will turn "OFF" and the system will function as normal. If a lock cylinder circuit fault (lock cylinder contacts or wiring becomes open or shorted, or if a defective key is detected) while the Engine is "RUNNING", the vehicle can be restarted. The "SECURITY" Indicator will illuminate during this Ignition cycle while the fault is present. When a fault condition is present at the time Ignition is cycled off, the vehicle will not be protected by the PASS-Key-II System and the indicator will be illuminated whenever the Ignition is on, until the fault is corrected. This is called the Fault Enable Mode. After the fault has been corrected, the "SECURITY" Indicator will remain "ON" for approximately one minute then go "OFF."
Key Code and Resistance Chart
PASS-Key II System
Key Code And Resistance Chart

So in conclusion, you can see that your engine will not start without the key resistance input. You can also see in the column the small wire that transfers this resistance to the BCM. The wires are extremely tiny & break often. I would contact your dealer ASAP & Get the parts to fix it, or get it to a shop that can ASAP. It's Saturday. If you want to give it a shot, I can help you through it, but you'll need some special column tools like a lock plate compressor, steering wheel puller, & various hand tools.

Let me know.