Lexus NX: Security Indicator Light Does not Blink
DESCRIPTION
- The certification ECU (smart key ECU assembly) blinks the security indicator light (air conditioning control assembly) when the immobiliser is set (power switch off, or driver door is opened and closed with power switch on (IG)).
- The certification ECU (smart key ECU assembly) receives the security indicator light signal from the main body ECU (multiplex network body ECU) via CAN communication when the theft deterrent system is in the arming preparation state or alarm sounding state. Then, the certification ECU (smart key ECU assembly) blinks the security indicator light (air conditioning control assembly).
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
-
The immobiliser system uses the CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the immobiliser system after confirming that the communication systems are functioning properly.
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- When using the Techstream with the power switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Access. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
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Before replacing the certification ECU (smart key ECU assembly) or main body ECU (multiplex network body ECU), refer to Registration.
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PROCEDURE
| 1. | CHECK FOR DTC |
(a) Check for DTCs.
Body Electrical > Smart Access > Trouble Codes Powertrain > Hybrid Control > Trouble CodesOK:
DTCs are not output.
| NG | .gif) | GO TO DIAGNOSTIC TROUBLE CODE CHART |
|
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| 2. | PERFORM ACTIVE TEST USING TECHSTREAM (IMMOBILISER INDICATOR) |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Smart Access / Active Test.
(e) Perform the Active Test according to the display on the Techstream.
Body Electrical > Smart Access > Active Test| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Immobiliser Indicator | Security indicator light | OFF/ON | - |
| Tester Display |
|---|
| Immobiliser Indicator |
OK:
The security indicator light (air conditioning control assembly) operates normally.
| NG | | GO TO STEP 4 |
|
| 3. | CHECK SECURITY INDICATOR LIGHT (AIR CONDITIONING CONTROL ASSEMBLY) OPERATION |
(a) When the immobiliser is set, check that the security indicator light (air conditioning control assembly) blinks.*1
OK:
The security indicator light (air conditioning control assembly) blinks normally.
(b) When the theft deterrent system is in the arming preparation state, check that the security indicator light (air conditioning control assembly) illuminates.*2
OK:
The security indicator light (air conditioning control assembly) illuminates normally.
| Result | Proceed to |
|---|---|
| *1 is NG (*2 is OK) | A |
| *2 is NG (*1 is OK) | B |
| A | | REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
| B | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| 4. | CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - SECURITY INDICATOR LIGHT AND BODY GROUND) |
(a) Disconnect the I53 certification ECU (smart key ECU assembly) connector.
(b) Disconnect the I13 security indicator light (air conditioning control assembly) connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| I53-19 (IND) - I13-4 (LP) | Always | Below 1 Ω |
| I53-19 (IND) or I13-4 (LP) - Body ground | Always | 10 kΩ or higher |
| I13-14 (GND) - Body ground | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 5. | CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
(a) Connect the I53 certification ECU (smart key ECU assembly) connector.
(b) Connect the I13 security indicator light (air conditioning control assembly) connector.
(c) Using an oscilloscope, check the waveform.
| *a | Component with harness connected (Certification ECU (Smart Key ECU Assembly)) | - | - |
Measurement Condition:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| I53-19 (IND) - Body ground | Power switch off → on (IG) | Pulse generation → Below 2 V |
| OK | | REPLACE SECURITY INDICATOR LIGHT (AIR CONDITIONING CONTROL ASSEMBLY) |
| NG | | REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
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