PATS PIDs

Monitoring the PATS PIDs can be very useful in determining which diagnostic steps to follow. Viewing the MASTERKEY (master key) PID with both keys will determine if the key is a programmed key and may also be used to prove out the transceiver, circuitry and the IC. A master key is a key that is programmed into the IC. Viewing the MIN_KEY (minimum number of keys) PID (this PID does not change) determines the minimum number of keys that must be programmed into the IC. There must be at least 2 keys programmed into the IC in this type of PATS before the vehicle will start. Viewing the N_KEYCODE (number of keys programmed) PID will determine if the minimum number of keys have been programmed into the IC. If the N_KEYCODE PID reads 0 or 1, additional key(s) will need to be programmed into the IC in order to meet the minimum of 2 keys. If the N_KEYCODE PID reads 0 or 1, and the MASTERKEY PID reads NOTPREST, that particular key must be programmed into the IC. If the N_KEYCODE PID reads 1, and the MASTERKEY PID reads PRESNT, that particular key is already programmed into the IC. In this particular case, though, there are not enough keys programmed (a minimum of 2 are needed before the vehicle will start) into the IC and at least 1 more key will need to be programmed before the vehicle will start. Refer to Integrated Key head Transmitter (IKT) Key Programming Using Diagnostic Equipment .

Also, if the unlimited key mode has been enabled, the N_KEYCODE PID will always read 2, after the first 2 keys are programmed into the IC, regardless of how many additional keys are added.

If the IC was replaced, the parameters in the IC, and the parameters in the PCM will need to be reset. When the parameters in the IC are reset, it clears (erases) the PCM ID from the IC. A PCM parameter reset will cause the PCM to send a PCM ID to the IC that is necessary for the system to operate. Make sure to cycle the key at least once, then turn the key ON and make an attempt to start the vehicle for 3-5 seconds before attempting more procedures. If only a PCM parameter reset occurs, the ID stored in the IC will not match the ID being sent by the PCM, and may cause a PATS-related no-start. Carry out a PATS parameter reset, then turn the key ON and make an attempt to start the vehicle for 3-5 seconds before attempting more procedures.

If the PCM ID (PCM id status) PID reads STORED, the IC has a PCM ID stored. If it reads NOTSTRD, a parameter reset of the PCM may resolve this issue. If the PATSENABL (vehicle enable status) PID reads DISABLED, and the N_KEYCODE PID reads 2 or more and the MASTERKEY PID reads PRESNT, the IC, and the PCM will need to have their parameters reset. Refer to Passive Anti-Theft System (PATS) Parameter Reset .

If the PATSENABL PID reads DISABLED, and the N_KEYCODE PID reads 1 and the MASTERKEY PID reads PRESNT, or if the N_KEYCODE PID reads 0 and the MASTERKEY PID reads NOTPRESNT, a minimum of 2 keys will need to be programmed into the IC. Refer to Integrated Key head Transmitter (IKT) Key Programming Using Diagnostic Equipment .

If the MASTERKEY PID continues to read NOTPRESNT after programming, this may indicate a defective key. The SPAREKEY PID is defaulted to ENABLED. With the SPAREKEY PID displaying ENABLED, the IC will accept more than 2 keys (up to a maximum of 8) being programmed into the IC using Key Programming Using Two Programmed Keys . It can be toggled to DISABLED if the customer wants to disable the customer spare key programming function. Refer to Key Programming Switch State Control . This switch state control does not affect the Key Programming Using Diagnostic Equipment procedure.

In summary, for the PATS PIDs and their correct state in order for the vehicle to start: