Principles of Operation

Anti-Theft

Principles of Operation

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

NOTE: Make sure any non-Ford aftermarket remote start systems have been removed from the vehicle before any PATS-related no-start concerns are investigated.

NOTE: A minimum of 2 PATS keys must be programmed into the IC before the vehicle starts.

NOTE: When using the Integrated Diagnostic System (IDS), the IC and the Transmission Control Module (TCM) parameters are reset at the same time.

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

Anti-Theft Indicator

PATS uses a visual anti-theft indicator located in the IC. 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 concern, this indicator either flashes rapidly or glows steadily when the ignition key is turned to the ON or START position. PATS 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. Retrieve DTCs from the IC and the TCM to determine if there are any PATS-related DTCs that can indicate the cause of the no-start. GO to Symptom Chart. Anti-Theft - Passive Anti-Theft System (PATS)

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

A PATS no-start can involve a vehicle no-start due to the Electronically Controlled Continuously Variable Transmission (eCVT) not cranking the engine or allowing electric drive. If the PATS anti-theft indicator does not prove out and one (or both) of the previous conditions are present, it can be due to a PATS concern. If the anti-theft indicator proves out, and the vehicle does not start, it is probably not a PATS concern. Refer to Computers and Control Systems Information. If the anti-theft indicator does not illuminate at all, it can be an IC concern.

Encoded Passive Anti-Theft System (PATS) Keys

PATS 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 portion of the IKT key does not require batteries and should last the lifetime of the vehicle. The transmitter portion of the IKT key does have a battery. Each IKT (PATS) key must be programmed into the IC before it can be used to start the vehicle. A maximum of 4 IKT keys can be programmed to start the vehicle and also operate the RKE functions. If more than 4 IKT keys are programmed, the RKE portion of the additional IKT keys does not operate and the SJB (and the IC) sets a memory full DTC B1138. These additional keys start the vehicle, but does not operate the RKE system. If additional PATS keys are desired, a standard PATS key (a non-IKT key) can be used. There are special diagnostic procedures described that must be carried out if a new PATS key is necessary. Refer to Integrated Keyhead Transmitter (IKT) Key Programming Using Diagnostic Equipment Using Diagnostic Equipment or Key Programming Using Two Programmed Keys Using Two Programmed Keys.

Passive Anti-Theft System (PATS) Transceiver

The PATS transceiver is located under the steering column shroud and communicates with the encoded ignition key. During each vehicle start sequence, the PATS transceiver reads the encoded ignition key identification code and sends data to the IC. The IC validates the code, and if it is the correct code, the IC sends a message to the TCM to allow the eCVT to start the engine and sends a message to the PCM to allow the fuel injectors to operate. Refer to Passive Anti-Theft System (PATS) Transceiver Service and Repair.

Passive Anti-Theft System (PATS) Operation

The PATS function is controlled by the IC. With this type of PATS, there are parameters that need to be reset if either the IC or the TCM (or both) is replaced. Refer to Passive Anti-Theft System (PATS) Parameter Reset Passive Anti-Theft System (PATS) Parameter Reset.

When the PATS key is turned to the ON or START position, the IC initiates the key interrogation sequence by sending a voltage signal to the PATS transceiver. The transceiver then uses its antenna to bounce a signal off the transponder in the PATS key. This process "reads" the PATS key identification code and sends the key identification code back to the IC, which interprets it and determines if it matches one of the stored key codes. If it does match one of the stored key codes, the IC sends messages to the TCM to allow the eCVT to crank the engine or enable electric drive. If it does not match one of the stored key codes, or it is only a partial key read or no key read, the IC does not allow the eCVT to start the engine or enable electric drive. The anti-theft indicator in the IC flashes (or may glow steadily) and the IC stores one or more DTCs. All elements of PATS must be functional before the vehicle starts. If any of the components are not working correctly, the vehicle cannot start. If the IC must be replaced for any reason (PATS concerns or any IC concerns), the PATS keys must be programmed into the new IC. Refer to Integrated Keyhead Transmitter (IKT) Key Programming Using Diagnostic Equipment Using Diagnostic Equipment.

PATS is not compatible with non-Ford aftermarket remote start systems, which allow the vehicle to be started from the exterior of the vehicle. These systems can reduce the security of the vehicle, and can also cause no-start concerns. Remote start systems must be removed from the vehicle before any PATS-related no-start concerns are investigated.

PATS disables the vehicle from starting if there is:

- a damaged PATS key.
- a non-programmed PATS key.
- a non-PATS key (key has no electronics).
- damaged wiring.
- a damaged transceiver.
- a damaged IC.
- a damaged TCM.
- IC and TCM parameters mismatched.

Passive Anti-Theft System (PATS) PIDs

Monitoring the PATS 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 IC. A master key is any key that is programmed into the IC. Viewing the MIN_KEYS (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 starts. Viewing the N_KEYCODE (number of keys programmed) PID determines if the minimum number of keys have been programmed into the IC. If the N_KEYCODE PID reads 0 or 1, additional key(s) needs 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 Not Present, that particular key must be programmed into the IC. If the N_KEYCODE PID reads 1, and the MASTERKEY PID reads Present, that particular key is already programmed into the IC. If the IC is replaced, the parameters in the IC, and the parameters in the TCM need to be reset.

When the parameters are reset, it clears (erases) the TCM ID from the IC and the IC ID from the TCM. Make sure to cycle the key at least once, then turn the key to the ON position and make an attempt to start the vehicle for 3-5 seconds before attempting more procedures. If only a TCM parameter reset occurs (if a TCM is replaced), the ID stored in the IC does not match the ID being sent by the TCM, and can cause a PATS-related no-start. Carry out the parameter reset in order to resolve these concerns. Passive Anti-Theft System (PATS) Parameter Reset

If the TCM ID PID (the scan tool displays the TCM ID as: PCM_ID) reads Stored, the IC has a TCM ID stored. If it reads Not Stored, a parameter reset of the TCM can resolve this concern. If the PCM_VFY PID reads No, and the N_KEYCODE PID reads 2 or more and the MASTERKEY PID reads Present, the IC, and the TCM need to have their parameters reset. Refer to Passive Anti-Theft System (PATS) Parameter Reset Passive Anti-Theft System (PATS) Parameter Reset.

If the PCM_VFY PID reads No, and 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 IC. Refer to Integrated Keyhead Transmitter (IKT) Key Programming Using Diagnostic Equipment Using Diagnostic Equipment.

If the MASTERKEY PID continues to read Not Present after programming, this can indicate a damaged key. The SPAREKEY PID is defaulted to ENABLE. With the SPAREKEY PID displaying ENABLE, the IC accepts more than 2 keys (up to a maximum of 8) being programmed into the IC using Key Programming Using Two Programmed Keys Using Two Programmed Keys. It can be toggled to DISABLE if the customer wants to disable the customer spare key programming function. Refer to Key Programming Switch State Control Switch State Control to change the state of the SPAREKEY PID. This switch state control affects the Key Programming Using Two Programmed Keys procedure.

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

NOTE: The TCM ID PID in the IC is displayed by the Integrated Diagnostic System (IDS) scan tool as PCM_ID

- 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 called unlimited key mode (PID UNL_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 key code. 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 Unlimited Key Mode.