1999 tahoe passlock issue

[c10 custom]

hi guys i am working on a 1999 chev tahoe and it has the passlock issue
it turns over great but olny runs for 5 seconds then shuts off security light is on
i changed the ignition switch and the part that contains the passlock sensor whitch is the part that the lock cyclinder goes into not sure where to go from here i tried the relearn procedure turn key to run position for 10 minutes then back off then tried to start and nothing any help would be greatly appreciated thank you

[clinebarger]

1. Access the Passlock sensor 3 wire connector. This is located in the ignition lock cylinder housing.

2. Leaving the connector plugged in, check for 12 volts on the White wire, and less than 0.05 volts on the Black wire. This is the power and ground provided by the Electric Variable Orifice (EVO)/Passlock module.

3. Disconnect the 3 wire connector and verify the module is sending out a 5 volt reference on the Yellow wire. If any of these voltages are incorrect, check for a problem with the wiring, or EVO/Passlock module.

4. Plug the connector back in. During cranking, a resistor in the Passlock sensor will lower the voltage on the Yellow wire. Verify the voltage always drops to the same level. If not, replace the lock cylinder housing and lock cylinder.

5. If the problem continues, replace the lock cylinder housing harness (the filter built into the harness sometimes fails).

6. Perform the relearn procedure by first turning the key to the crank position, then leaving the key on for a minimum of 10 minutes, key off for 10 seconds, then repeat two more times.

Tech tip....
The voltage that the Yellow wire drops to will be different for each vehicle because there are 10 different possible resistor values. In some cases, this problem is too intermittent to locate by testing. Common causes are the lock cylinder housing, lock cylinder, and the lock cylinder wiring harness and filter.

[c10 custom]

i do not have 12 volts on the yellow wire and the orange with black wire does have 0.05 volts on it when the 3 wire connector is disconnected there is no 5 volt reference on the yellow wire this truck does have a remote start

[clinebarger]

Originally Posted by c10 custom

i do not have 12 volts on the yellow wire and the orange with black wire does have 0.05 volts on it when the 3 wire connector is disconnected there is no 5 volt reference on the yellow wire this truck does have a remote start

The EVO/Passlock module will send out 5vdc on the yellow wire with the lock cylinder unplugged.......If it doesn't.....The module is bad, Or the harness has a open in it.

Your on you own with the remote start...It could cause problems But I don't know how to test it......Maybe an alarm guy can chime in on this.

[truckdude239]

i will chime in if it is an after market unit i'd remove it i've remopved many that cause a no start issuses

[c10 custom]

now my next question is where is the theft deterent module located on this
1999 chev tahoe