Kia Carens. Manual — part 305

state. The unlocked state allows engine start. The ICU communicates also with a Power Scan Tool in order to:

• Proceed with key (transponder) matching at the end of vehicle manufacturing line.
• Initialize the engine management system.
• Proceed with auto-test of the product (check of antenna connections and W line output).

In case of a transponder failure, the immobilizer can be unlocked with a procedure called Limp Home Procedure by
entering PIN (i.e. passcode) with the RR DEF SW.

ICU

• Transponder reader/exciter interface
• 5V power supply regulation
• Serial communication interface
• Lamp relay drivers
• Micro controller and software

Transponder reader/exciter

The communication with the transponder is done by an integrated circuit (ASIC) which intergrates in addition to the
transponder reader/exciter:

• 5V voltage regulator for intermal use and micro controller power supply.
• Watch dog circuit
• W line driver used for the communication with the ECM

Electrical characteristics of the ASIC:

• DC operational supply voltage:6V~16V
• 5V voltage regulator output:4.8V~5.2V

Transponder

The transponder used is the read only type in glass tube package. The transponder is inserted in the key by over molding
procedure at the steering column lock factory.

Antenna

The antenna is composed of:

• Coil
• Plastic holder for the coil and envelop
• 1 meter of 1pair of twisted wires cable
• AMP 3 position connector

Functions

Abbreviations

ECU

Electronic Control Unit or Engine Control Unit

EMS

Engine Management System

ECM

Engine Control Module (Same as ECU)

VIM

Vehicle Immobilizer

ICU

Inkey Control Unit

MIN

Model Identification Number

PIN

personal Identification Number (i.e. Passcode)

VIN

Vehicle Identification Number

Function list

Transponder communication : reads the transponder code and decide (in normal mode) the immobilizer condition
"Locked" or "Unlocked"
ECM communication:answer the requests from engine management system.
Diagnostic communication:answers the requests from diagnostic tool (Hi-Scan Pro Tool).
Limphome function:manages teh ignition and RR DEF SW input and handies the override procedure for the Limphome
and key learning sequence.

ICU condition and status

The ICU has two possible conditions: “Locked” or “Unlocked”.
In addition, three possible statuses :”Virgin”, “Learnt” and “Neutralized”.

Locked condition

The ICU will stay in the locked condition as long as no valid transponder code has been received. The ICU sill
automatically go to lock condition a regular time after key OFF. As long as the ICU is in the locked condition, engine start
is impossible, since the ICU answers any ECM request with dummy data. Exceptions to this rule are made if either the
ECM or the ICU is in virgin state.

Unlocked condition

Only if the ICU is in the unlocked condition, engine start is allowed.

Virgin status

This status represents the delivery condition of the ICU. The MIN has been programmed at the factory in EEPROM. The
VIN has not been programmed yet; it will be origrammed at the car manufacturer’s end-of -line test. In this status, if the
ECM is also in virgin state and the MIN of the ICU are the same, engine start is allowed.

Learnt status

This represents the normal operation of the ICU, where the VIN has been learned. When the ECM sends a request
containingthe same MIN, then if the ICU is unlocked, the response to the ECM will contain a code based on the VIN. If
the ICU is locked, the response will contain dummy data.

Neutralized status

To replace a part of the system(ICU, ECM), the ICU and the ECM have to be set to neutralized state by a <<read
passcode >> request from the diagnostic tool. In this status, engine start is never possible
Following flow diagtam shows the possible transitions between statyuses:

Status VS condition

The following table shows the possible conditions according the different possible status of the ICU :

Stetus

Condition

Condition for locked.unlocked

Remark

Virgin

Unlocked

Always

Enfine start is allowed provided the ECU
is virgin.

Neutralized

Locked

Ignition ON with an unknown key

Unlocked

Ignition ON with a unknown or override
procedure

ICU may neutralize an ECU provided
they both have similar MIN and VIN.

Learnt

Locked

Ignition ON with an unknown key

Unlocked

Ignition ON with a unknown or override
procedure

Engine start allowed provided ICU and
ECU have similar MIN and VIN

Normal environment of coil/transponder

The transponder(inserted in the Key) has two stable positions(position 1 and position2 on the above figure).
Reading the transponder in these conditions should be possible at 100% rate:

• in the temperature range
• in case if extreme values intervening in the coupling between transponder and coil, which are:

→ carrier frequency
→ tuning frequency of the antenna resonant circuit
→ tuning frequency of the transponder coil
→ minimum magnetic field of transponder good operation
→ mechanical tolerances of positioning(transponder in the key and coil on the SCL)

• When the system is submitted to an electromagnetic field

Functional description

The trading transponder procedure is initiated by a rising edge in the Ignition input.
The transponder reading should be completed during a delay of 200ms after + ignition rising edge. This time includes two
possible tentative of transponder reading.
During this delay, all other requests are ignored.
Four transponders in total can be programmed in the EEPROM.
The ICU is unlocked if the transponder code read is know and belongs to the list in the EEPROM and if the transponder
has been authenticated successfully. ICU switches to the locked state after approximately one second after the + ignition
falling edge (Passive arming).The ICU is locked if the transponder is absent or the code read is unknown.