Anti-Theft - Without Intelligent Access (IA)

Anti-Theft - Without Intelligent Access (IA)

Principles of Operation

NOTE: Replacement of the Passive Anti-Theft System (PATS) transceiver does not require the PATS (Passive Anti-Theft System) keys to be programmed into the Instrument Panel Cluster (IPC) again.

NOTE: Make sure any aftermarket remote start systems have been removed from the vehicle before any PATS (Passive Anti-Theft System) -related no-start concerns are investigated.

NOTE: A minimum of 2 PATS (Passive Anti-Theft System) keys must be programmed into the IPC (Instrument Panel Cluster) before the vehicle starts.

NOTE: If the IPC (Instrument Panel Cluster) or the PCM is being replaced (or both), the parameters must be reset in both modules or the vehicle experiences a PATS (Passive Anti-Theft System) no-start. Refer to Passive Anti-Theft System (PATS) Parameter Reset - Without Intelligent Access (IA) .

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

Anti-Theft Indicator

PATS (Passive Anti-Theft System) uses a visual anti-theft indicator located in the IPC (Instrument Panel Cluster). The anti-theft indicator proves out for 3 seconds when the ignition key is in the ON or START position under normal operation. If there is a PATS (Passive Anti-Theft System) concern, the anti-theft indicator either flashes rapidly or glows steadily when the ignition key is turned to the ON or START position. PATS (Passive Anti-Theft System) also flashes the anti-theft indicator every 2 seconds when the ignition key is in the OFF position to act as a visual theft deterrent. for information on the anti-theft indicator.

PATS (Passive Anti-Theft System) is active only for a few seconds when the vehicle is starting. It is not a PATS (Passive Anti-Theft System) concern if the vehicle stalls after it has been running for a minimum of 3 seconds. PATS (Passive Anti-Theft System) cannot disable a running vehicle.

A PATS (Passive Anti-Theft System) no-start may involve a vehicle no-start due to either the fuel injectors not operating or the starter not operating (or both). If the PATS (Passive Anti-Theft System) anti-theft indicator does not prove out and one (or both) of the previous conditions are present, it may be due to a PATS (Passive Anti-Theft System) issue. If the anti-theft indicator proves out, and the vehicle does not start, it is probably not a PATS (Passive Anti-Theft System) issue. Refer to Computers and Control Systems Information. If the anti-theft indicator does not illuminate at all, it may be an IPC (Instrument Panel Cluster) issue. GO to Symptom Chart for information. A low battery voltage condition may cause the PATS (Passive Anti-Theft System) to allow starter operation, but may keep the fuel injectors from operating. Anti-Theft - Without Intelligent Access (IA)

Encoded Passive Anti-Theft System (PATS) Keys

NOTE: A maximum of 8 PATS (Passive Anti-Theft System) keys can be programmed into the IPC (Instrument Panel Cluster).

PATS (Passive Anti-Theft System) uses a special ignition key, called an Integrated Keyhead Transmitter (IKT) key that is larger than a conventional ignition key. It contains a permanently-installed electronic device called a transponder and also has the Remote Keyless Entry (RKE) transmitter integrated into the keyhead. Each transponder contains a unique encrypted identification code which is one of a very large number of combinations. The addition of this transponder to the key makes it an "encoded" key. The PATS (Passive Anti-Theft System) key does not require batteries and should last the lifetime of the vehicle. The transmitter portion of the IKT (Integrated Keyhead Transmitter) key has a battery. Each PATS (Passive Anti-Theft System) key must be programmed into the IPC (Instrument Panel Cluster) before it can be used to start the vehicle. A maximum of 4 IKT (Integrated Keyhead Transmitter) keys can be programmed to start the vehicle and also operate the RKE (Remote Keyless Entry) functions. If more than 4 IKT (Integrated Keyhead Transmitter) keys are programmed, the RKE (Remote Keyless Entry) portion of the additional IKT (Integrated Keyhead Transmitter) keys does not operate and the SJB (Smart Junction Box) sets DTC B1138 (Memory Full). The IPC (Instrument Panel Cluster) sets DTC B109E:42 (Remote Keyless Entry: General Memory Failure). The memory that is full is referring to the memory in the SJB (Smart Junction Box). These additional keys (more than 4 IKT (Integrated Keyhead Transmitter) keys) that have been programmed start the vehicle, but cannot operate the RKE (Remote Keyless Entry) system. If additional PATS (Passive Anti-Theft System) keys are desired (more than 4, up to 8 total, IKT (Integrated Keyhead Transmitter) and PATS (Passive Anti-Theft System)), a standard PATS (Passive Anti-Theft System) key (a non-IKT (Integrated Keyhead Transmitter) key) can be used. There are special procedures described that must be carried out if a new PATS (Passive Anti-Theft System) key is necessary. Refer to Key Programming Using Diagnostic Equipment - Without Intelligent Access (IA) or Key Programming Using Two Programmed Keys - Without Intelligent Access (IA) .

Passive Anti-Theft System (PATS) Transceiver

The PATS (Passive Anti-Theft System) transceiver is located on the instrument panel, to the right of the steering wheel and communicates with the encoded ignition key. During each vehicle start sequence, the PATS (Passive Anti-Theft System) transceiver reads the encoded ignition key identification code and sends data to the IPC (Instrument Panel Cluster). The IPC (Instrument Panel Cluster) validates the code, and if it is the correct code, sends a message to the PCM to ground the starter relay solenoid coil and to also allow the fuel injectors to operate.

Passive Anti-Theft System (PATS) Operation

The PATS (Passive Anti-Theft System) function is controlled by the IPC (Instrument Panel Cluster). With this type of PATS (Passive Anti-Theft System), there are parameters that need to be reset if either the IPC (Instrument Panel Cluster) or the PCM (or both) are replaced. Refer to Passive Anti-Theft System (PATS) Parameter Reset - Without Intelligent Access (IA) .

When the PATS (Passive Anti-Theft System) key is turned to the ON or START position, the IPC (Instrument Panel Cluster) initiates the key interrogation sequence by sending a voltage signal to the PATS (Passive Anti-Theft System) transceiver. The transceiver then uses its antenna to bounce a signal off the transponder in the PATS (Passive Anti-Theft System) key. This process "reads" the PATS (Passive Anti-Theft System) key identification code and sends the key identification code back to the IPC (Instrument Panel Cluster), which interprets it and determines if it matches one of the stored keycodes. If it does match one of the stored keycodes, the IPC (Instrument Panel Cluster) sends a message to the PCM to ground the starter relay solenoid coil and to also allow the fuel injectors to operate. If it does not match one of the stored keycodes, or it is only a partial key read or no key read, the IPC (Instrument Panel Cluster) sends a message to the PCM to not ground the starter relay solenoid coil and not allow fuel injector operation. The anti-theft indicator in the IPC (Instrument Panel Cluster) flashes (or may glow steadily) and the IPC (Instrument Panel Cluster) stores one or more DTCs.

All elements of PATS (Passive Anti-Theft System) must be functional before the vehicle starts. If any of the components are not working correctly, the vehicle cannot start.

If the IPC (Instrument Panel Cluster) must be replaced for any reason (PATS (Passive Anti-Theft System) issues or IPC (Instrument Panel Cluster) issues), the PATS (Passive Anti-Theft System) keys must also be programmed into the new IPC (Instrument Panel Cluster). Refer to Key Programming Using Diagnostic Equipment - Without Intelligent Access (IA) .

PATS (Passive Anti-Theft System) disables the vehicle from starting if there is:

- a damaged PATS (Passive Anti-Theft System) key.

- a non-programmed PATS (Passive Anti-Theft System) key.

- a non-PATS (Passive Anti-Theft System) key (key has no electronics).

- damaged wiring.

- a damaged transceiver.

- a damaged IPC (Instrument Panel Cluster).

- a damaged PCM.

Passive Anti-Theft System (PATS) PIDs

Monitoring the PATS (Passive Anti-Theft System) PIDs can be very useful in determining which diagnostic steps to follow. Viewing the MASTERKEY (verifies if the key is programmed) PID (with both keys) determines if the key is a programmed key and also proves out the transceiver, circuitry and the IPC (Instrument Panel Cluster). A master key is any key that is programmed into the IPC (Instrument Panel Cluster). Viewing the MIN_KEYS (minimum number of keys) PID (this PID does not change) indicates the minimum number of keys that must be programmed into the IPC (Instrument Panel Cluster) for the vehicle to start. There must be at least 2 keys programmed into the IPC (Instrument Panel Cluster) in this type of PATS (Passive Anti-Theft System) before the vehicle starts. Viewing the N_KEYCODE (number of keys programmed) PID determines if the minimum number of keys has been programmed into the IPC (Instrument Panel Cluster). If the N_KEYCODE PID reads 0 or 1, additional key(s) need to be programmed into the IPC (Instrument Panel Cluster) to meet the minimum of 2 keys. If the N_KEYCODE PID reads 0 or 1, and the MASTERKEY PID reads Not Present, that particular key must be programmed into the IPC (Instrument Panel Cluster). If the N_KEYCODE PID reads 1, and the MASTERKEY PID reads Present, that particular key is already programmed into the IPC (Instrument Panel Cluster). The SPAREKEY (spare key) PID is defaulted to ENABLE.

When the parameters in the IPC (Instrument Panel Cluster) are reset, it clears (erases) the PCM ID from the IPC (Instrument Panel Cluster). A PCM parameter reset causes the PCM to send a PCM ID to the IPC (Instrument Panel Cluster) 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 IPC (Instrument Panel Cluster) does not match the ID being sent by the PCM, and may cause a PATS (Passive Anti-Theft System) -related no-start. Carry out the parameter reset, and do not cycle the key until after the parameter reset selection has been highlighted, and the tick mark has been pressed. The Integrated Diagnostic System (IDS) then resets the parameters in both the IPC (Instrument Panel Cluster) and the PCM at the same time.

If the PCM_ID reads Stored, the IPC (Instrument Panel Cluster) has a PCM ID stored. If it reads Not Stored, a parameter reset of the PCM may resolve this issue. If the PCM_VFY PID (PCM verify) reads No, the N_KEYCODE PID reads 2 or more and the MASTERKEY PID reads Present, the IPC (Instrument Panel Cluster) and the PCM need to have their parameters reset. Refer to Passive Anti-Theft System (PATS) Parameter Reset - Without Intelligent Access (IA) .

If the PCM_VFY PID reads No, the N_KEYCODE PID reads 1 and the MASTERKEY PID reads Present, or if the N_KEYCODE PID reads 0 and the MASTERKEY PID reads Not Present, a minimum of 2 keys need to be programmed into the IPC (Instrument Panel Cluster). Refer to Key Programming Using Diagnostic Equipment - Without Intelligent Access (IA) .

The IPC (Instrument Panel Cluster) SPAREKEY PID is defaulted to ENABLE. With the SPAREKEY PID displaying ENABLE, the IPC (Instrument Panel Cluster) accepts more than 2 keys (up to a maximum of 8) being programmed into the IPC (Instrument Panel Cluster) using the Key Programming Using Two Programmed Keys - Without Intelligent Access (IA) procedure. The SPAREKEY PID can be toggled to Disable if the customer wants to disable the customer spare key programming function. To enable or disable the spare key feature, refer to Key Programming Switch State Control - Without Intelligent Access (IA) . This switch state control does not affect the Key Programming Using Diagnostic Equipment - Without Intelligent Access (IA) procedure.

In summary, for the PATS (Passive Anti-Theft System) PIDs and their correct state in order for the vehicle to start:

- N_KEYCODE must read 2 or more

- MASTERKEY must read Present

- PCM_ID must read Stored

- PCM_VFY must read Yes

Unlimited Key Mode

This system contains a feature named unlimited key mode that has a PID of UNL_KEY_MODE (unlimited key mode). This feature allows a customer to program more than 8 keys to their vehicle if they request it. Each vehicle in unlimited key mode is set up with a special unlimited transponder security keycode. This allows all the customer vehicles to share the same mechanically cut keys, but no other keys from outside can be used to operate the vehicles. For an individual customer, any randomly selected security key that has been previously mechanically cut and electronically programmed to the vehicle is acceptable. Refer to Spare Key Programming - Unlimited Key Mode .