Engine Imobilizer: Overview Lexus IS II

SYSTEM DESCRIPTION

1. ENGINE IMMOBILIZER SYSTEM DESCRIPTION The immobilizer system is a theft deterrent system that determines whether to disable starting of the SFI system based on a comparison of the key's ID code and the vehicle's pre-registered code. The immobilizer system compares the vehicle certification ECU's pre-registered ID code with the ID of the key-embedded transponder chip. If the ID codes do not match, the immobilizer system activates and the SFI system cannot be started. The certification ECU manages communication with the ECM, power source control ECU, steering lock ECU and ID code box. When the ID codes of the transponder chip and certification ECU match, the certification ECU authorizes the starting of the SFI system.
2. FUNCTION OF MAIN COMPONENT FUNCTION OF MAIN COMPONENT Component Outline Transponder key coil/amplifier (built into engine switch) Receives key ID code, amplifies ID code and outputs the code to the certification ECU. Indoor electrical key oscillator Transmits key detection signals within the detection area in the vehicle interior upon receiving a transmission request signal from the certification ECU. Certification ECU request signal is activated when the key is brought into the vehicle interior and the engine switch is pushed. Door control receiver Receives an ID code from the key in the actuation area and transmits it to the certification ECU. Security indicator Illuminates or starts flashing. Illumination is controlled by the main body ECU RH.
3. SYSTEM FUNCTION Using entry function When the driver (or passenger) is sitting in the vehicle while carrying the key, and the engine switch is pressed while the brake pedal is depressed, the power source control ECU recognizes that the engine start operation has occurred and sends a certification request signal to the certification ECU. Upon receipt of the certification request signal, the certification ECU sends a request signal to the indoor electrical key oscillator. Upon receipt of the request signal, the indoor electrical key oscillator sends a request signal to detect if the key is inside the vehicle. When the key receives this request signal, it answers by sending an ID code containing a response code through the glass antenna to the door control receiver. Upon receipt of the ID code, the certification ECU analyzes the code. If the interior certification passes, then the power source control ECU sends a certification pass response signal. When the power source control ECU receives this signal, the ACC relay is switched on and the IG1 and IG2 relays are switched on in sequence. At this time, the engine switch indicator illuminates in green. Then the certification ECU checks that the power source mode has been changed and sends a steering lock command signal to the power source control ECU. After receiving this signal, the power source control ECU supplies power to the steering lock actuator. Then (via the ID code box) the steering lock ECU confirms that the certification ECU is certified and drives the steering actuator's motor until the steering lock is unlocked. After unlocking the steering lock, an unlock completed signal is sent to the certification ECU. Upon receipt of this signal, the certification ECU sends an unset command signal to the ID code box. Once this signal is received, the ID code box confirms that the certification ECU is certified, sends an immobilizer unset command signal to the ECM and sends a security indicator light off signal to the main body ECU RH. Not using the entry function (when key battery is depleted) When the driver is sitting in the vehicle while carrying the key and the brake pedal is depressed, the power source ECU recognizes that the stop light switch is on and sends a key confirmation request signal to the certification ECU. Upon receipt of this signal, the certification ECU drives the engine switch's built-in immobilizer amplifier. At this time the engine switch sends an RF wave communication signal to the immobilizer. If the driver holds the key up to the engine switch at this time, the engine switch receives the immobilizer RF wave signal and responds by sending a radio wave signal. When the engine switch receives the radio wave signal from the key, it duplicates the signal and sends an ID code to the certification ECU. Upon receipt of the ID code, the code is analyzed. If the certification passes, a key certification pass response signal is sent to the power source control ECU while simultaneously sending a sound buzzer request signal to the meter ECU. When the power source control ECU receives this signal, the ACC relay is switched on and the IG1 and IG2 relays are switched on in sequence. At this time, the engine switch indicator illuminates in green. Then the certification ECU checks that the power source mode has been changed and sends a steering lock command signal to the power source control ECU. After receiving this signal, the power source control ECU supplies power to the steering lock actuator. Then (via the ID code box) the steering lock ECU confirms that the certification ECU is certified and drives the steering actuator's motor until the steering lock is unlocked. After unlocking the steering lock, an unlock completed signal is sent to the certification ECU. Upon receipt of this signal, the certification ECU sends an unset command signal to the ID code box. Once this signal is received, the ID code box confirms that the certification ECU is certified, sends an immobilizer unset command signal to the ECM and sends a security indicator light off signal to the main body ECU RH.

DESCRIPTION

This DTC is output when there is an open or short malfunction in the key coil (built into engine switch).

DTC DETECTION CONDITION - TROUBLE AREA TABLE

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1. CHECK DTC OUTPUT Delete the DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Recheck for DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2784 output reoccurs A B2784 output does not reoccur B B: END A: Go to next step
2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ENGINE SWITCH) Disconnect the P33 ECU and J31 switch connectors. Measures the resistance according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S39893388332006062400000). Standard resistance TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition P33-9 (CODE) - J31-10 (CODE) Always Below 1 ohms P33-8 (TXCT) - J31-9 (TXCT) Always Below 1 ohms P33-9 (CODE) - Body ground Always 10 k ohms or higher P33-8 (TXCT) - Body ground Always 10 K ohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. REPLACE ENGINE SWITCH Replace the engine switch (See «REMOVAL»(ref-235562-S27222868682006062400000) for 4GR-FSE, See «REMOVAL»(ref-235447-S24564960092006062200000) for 2GR-FSE).
4. CHECK ENGINE START Check that the engine starts. OK: The engine starts. NG: REPLACE CERTIFICATION ECU OK: END

This DTC is output when LIN communication from the certification ECU stops for a certain amount of time.

DTC DETECTION CONDITION - TROUBLE AREA TABLE

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1. CHECK HARNESS AND CONNECTOR (LIN COMMUNICATION LINE AND BODY GROUND) Disconnect the P33, J29, J55 and J69 ECU connectors. Measure the resistance according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S00946140762006062400000). Standard resistance TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition P33-10 (LIN) - J69-3 (LIN1) Always Below 1 ohms P33-10 (LIN) - J55-30 (LIN1) Always Below 1 ohms P33-10 (LIN) -J29-5 (LIN) Always Below 1 ohms P33-10 (LIN) - Body ground Always 10 K ohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK DTC OUTPUT Delete the DTCs (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Recheck for DTCs (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2785 and B2786 outputs reoccur A B2785 and B2789 outputs reoccur B B2785 output reoccurs C B: Go to step 6 C: Go to step 10 A: Go to next step
3. REPLACE STEERING LOCK ECU Replace the steering lock ECU.
4. ECU CODE REGISTRATION Register the ECU communication ID between the ECUs connected by LIN communication (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
5. CHECK DTC OUTPUT Check for DTCs (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2785 and B2786 outputs reoccur A B2785 and B2786 outputs do not reoccur B B: END A: REPLACE CERTIFICATION ECU
6. REPLACE ID CODE BOX
7. ELECTRICAL KEY REGISTRATION Register the electrical key code in the certification ECU (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
8. ECU COMMUNICATION ID REGISTRATION Register the ECU communication ID between the ID code box and ECM (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
9. CHECK DTC OUTPUT Check for DTCs (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2785 and B2789 outputs reoccurs A B2785 and B2789 outputs do not reoccur B B: END A: REPLACE CERTIFICATION ECU
10. REPLACE CERTIFICATION ECU Replace the certification ECU.
11. ELECTRICAL KEY REGISTRATION Register the electrical key code in the certification ECU (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
12. ECU COMMUNICATION ID REGISTRATION Register the ECU communication ID between the ID code box and ECM (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
13. CHECK DTC OUTPUT Check for DTCs (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2785 output reoccurs A B2785 output does not reoccur B B: END A: REPLACE POWER SOURCE CONTROL ECU

This DTC is output when the engine switch power source supply line is open or short.

DTC DETECTION CONDITION - TROUBLE AREA TABLE

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1. CHECK WIRE HARNESS (CERTIFICATION ECU - ENGINE SWITCH) Disconnect the P33 and J31 switch connectors. Measure the resistance according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S42066727062006062400000). Standard resistance TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition P33-30 (VC5) - J31-14 (VC5) Always Below 1 ohms P33-40 (AGND) - J31-8 (AGND) Always Below 1 ohms P33-17 (E) - Body ground Always Below 1 ohms P33-30 (VC5) - Body ground Always 10 K ohms or higher P33-40 (AGND) - Body ground Always 10 K ohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK HARNESS AND CONNECTOR Reconnect P33 ECU and J31 switch connectors. Measures the voltage according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S21631792072006062400000). Standard voltage TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition P33-30 (VC5) - Body ground Key is not in cabin Below 1 V Press engine switch 4.6 to 5.4 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR Measures the resistance according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S35953644132006062400000). Standard resistance TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition P33-17 (E) - Body ground Always Below 1 ohms NG: REPLACE CERTIFICATION ECU OK: REPLACE ENGINE SWITCH

This DTC is output when the ID code box detects an internal malfunction.

DTC DETECTION CONDITION - TROUBLE AREA TABLE

This DTC is output when the ID code box dose not respond to a verification request signal from the ECM.

HINT

If the engine switch is turned off immediately after an engine start, this DTC is also detected.

DTC DETECTION CONDITION - TROUBLE AREA TABLE

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1. CHECK DTC OUTPUT Delete the DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Recheck for DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2791 DTC output A No DTC output B B: USE SIMULATION METHOD TO CHECK A: Go to next step
2. ECU COMMUNICATION ID REGISTRATION Register the ECU communication ID between the ID code box and ECM (See «REGISTRATION»(ref-235584-S37552517312006062400000) ). Recheck for DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2791 DTC output A No DTC output B B: END A: Go to next step
3. CHECK HARNESS AND CONNECTOR (ID CODE BOX - ECM) Disconnect the J69 ECU and A6 ECM connectors. Measures the resistance according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S28167250682006062400000). Standard resistance TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition J69-6 (EFIO) - A6-6 (IMI) Always Below 1 ohms J69-6 (EFIO) - Body ground Always 10 K ohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. REPLACE ID CODE BOX Replace the ID code box.
5. ELECTRICAL KEY REGISTRATION Register the electrical key code in the certification ECU (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
6. ECU COMMUNICATION ID REGISTRATION Register the ECU communication ID between the ID code box and ECM (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
7. CHECK DTC OUTPUT Delete the DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Recheck for DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2791 DTC output A No DTC output B A: REPLACE ECM B: END

This DTC is output when one of the following occurs: 1) the ECM detects errors in its own communications with the ID code box; 2) the ECM detects errors in the communication lines; or 3) the ECU communication ID between the ID code box and ECM is different and an engine start is attempted. Before troubleshooting for this DTC, make sure no certification ECU DTCs are present. If present, troubleshoot the certification ECU DTCs first.

DTC DETECTION CONDITION - TROUBLE AREA TABLE

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1. CHECK DTC OUTPUT Delete the DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Recheck for DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2791 output reoccurs A B2791 output does not reoccur B B: GO TO «DTC B2791»(ref-235584-S38390225472006062400000) A: Go to next step
2. ECU COMMUNICATION ID REGISTRATION Register the ECU communication ID between the ID code box and ECM (See «REGISTRATION»(ref-235584-S37552517312006062400000) ). Check for DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2799 output reoccurs A B2799 output does not reoccur B B: END A: Go to next step
3. CHECK HARNESS AND CONNECTOR (ID CODE BOX - ECM) Disconnect the J69 ECU and A6 ECM connectors. Measure the resistance according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S41680355542006062400000). Standard resistance TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition J69-5 (EFII) - A6-7 (IMO) Always Below 1 ohms J69-5 (EFII) - Body ground Always 10 K ohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. REPLACE ID CODE BOX Replace the ID code box.
5. ELECTRICAL KEY REGISTRATION Register the electrical key code in the certification ECU (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
6. ECU COMMUNICATION ID REGISTRATION Register the ECU communication ID between the ID code box and ECM (See «REGISTRATION»(ref-235584-S37552517312006062400000) ).
7. CHECK DTC OUTPUT Check for DTC (See «DTC CHECK/CLEAR»(ref-235584-S32897595192006062400000) ). Result RESULT TABLE Result Proceed to B2799 output reoccurs A B2799 output does not reoccur B A: REPLACE ECM B: END

This circuit provides power to operate the ID code box.

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1. INSPECT FUSE (SECURITY) Remove the SECURITY fuse from the cowl side junction block RH. Measure the resistance of the fuse. Standard resistance: Below 1 ohms NG: REPLACE FUSE OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (ID CODE BOX - BATTERY) Disconnect the J69 ECU connector. Measure the voltage according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S12343715592006062400000). Standard voltage TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition J69-1 (+B) - Body ground Always 10 to 14 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (ID CODE BOX - BODY GROUND) Measure the resistance according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S02073217682006062400000). Standard resistance TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition J69-8 (GND) - Body ground Always Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

This circuit provides power to operate the certification ECU.

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1. INSPECT FUSE (SECURITY) Remove the SECURITY fuse from the cowl side junction block RH. Measure the resistance of the fuse. Standard resistance: Below 1 ohms NG : REPLACE FUSE OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - BATTERY) Disconnect the P33 ECU connector. Measure the voltage according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S28953941852006062400000). Standard voltage TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition P33-1 (+B1) - Body ground Always 10 to 14 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - BODY GROUND) Measure the resistance according to the value(s) in «TERMINAL CONNECTION SPECIFIED CONDITION TABLE»(ref-235584-S23889996102006062400000). Standard resistance TERMINAL CONNECTION SPECIFIED CONDITION TABLE Tester Connection Condition Specified Condition P33-17 (E) - Body ground Always Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

See also:
• SFI SYSTEM