Multiplex Communication (Diagnostic Codes & Circuit Tests): Overview Lexus IS II facelift

DESCRIPTION

1. This DTC is detected when communication between the main body ECU RH (cowl side J/B RH) and gateway ECU stops for more than 10 seconds.

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1. This DTC is detected when communication between the AFS ECU and the gateway ECU stops for more than 10 seconds.

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1. This DTC is detected when communication between the multiplex network master switch (power window master switch) and gateway ECU stops for more than 10 seconds.

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HINT

This DTC is only output on vehicles equipped with a smart access with push-button start.

1. This DTC is detected when communication between the certification ECU and gateway ECU stops for more than 10 seconds.

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1. This DTC is detected when communication between the outer mirror control ECU RH (Passenger Side Outer Mirror ECU) and gateway ECU stops for more than 10 seconds.

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1. This DTC is detected when communication between the outer mirror control ECU LH (Driver Side Outer Mirror) and gateway ECU stops for more than 10 seconds.

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HINT

This DTC is only output on vehicles equipped with a smart access with push-button start.

1. This DTC is detected when communication between the power source control ECU stops for more than 10 seconds.

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1. INSPECT FUSE (AM2) Remove the AM2 fuse from the cowl side J/B RH. Measure the resistance of the fuse. Standard resistance Below 1 ohms NG --> REPLACE FUSE OK: Go to next step
2. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - BATTERY AND BODY GROUND) Disconnect the J55 ECU connector. Measure the resistance and voltage of the wire harness side connector. Standard voltage Tester Connection Condition Specified Condition J55-33 (AM1) - Body ground Always 10 to 14 V J55-12 (AM2) - Body ground Always 10 to 14 V Standard resistance Tester Connection Specified Condition J55-6 (GND2) - Body ground Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK RESISTANCE OF COMMUNICATION LINE Disconnect the J55, J26 and 2F ECU connectors. Measure the resistance between the specified terminals on the wire harness side connectors. Standard resistance Tester Connection Specified Condition MPX1 (J55-7) - MPX2 (J26-7) Below 1 ohms MPX2 (J55-24) - 2F-5 Below 1 ohms Result Result Proceed to Both are OK A One is OK B Both are NG C C --> REPAIR OR REPLACE HARNESS OR CONNECTOR B --> REPLACE POWER SOURCE CONTROL ECU AND REPAIR OR REPLACE HARNESS OR CONNECTOR A --> REPLACE POWER SOURCE CONTROL ECU

1. This DTC is detected when communication between the tilt and telescopic ECU and the gateway ECU stops for more than 10 seconds.

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1. When a +B short circuit or body ground short circuit is detected on the door system communication bus (BEAN), BEAN is disabled and a DTC is output.

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1. CHECK DIAGNOSTIC TROUBLE CODE (A ECU) Disconnect the A ECU connector and check for DTCs B1214 and B1215. OK Neither DTC B1214 nor DTC B1215 is output. NOTE: Reconnect the connector before starting the next check. HINT: The A ECU in the door system bus represents the main body ECU RH. If the result is as specified, the disconnected A ECU (main body ECU RH) is malfunctioning. OK --> REPLACE A ECU NG: Go to next step
2. CHECK DIAGNOSTIC TROUBLE CODE (B ECU) Disconnect the A ECU and B ECU connectors and check for DTCs B1214 and B1215. OK Neither DTC B1214 nor DTC B1215 is output. NOTE: Disconnect the connectors one by one. Reconnect the connectors before starting the next check. HINT: Remove the B ECUs in the following order: Tilt and telescopic ECU Power window master switch Certification ECU Power source control ECU Position control ECU and switch (Front RH seat) Position control ECU and switch (Front LH seat) Main body ECU LH Outer mirror control ECU (RH) Outer mirror control ECU (LH) Front controller Overhead J/B Rain sensor Sliding roof control ECU If the result is as specified, the disconnected B ECU (one of the ECUs from the above list) or the wire harness between the A ECU and B ECU is malfunctioning. After the DTC is cleared, proceed to the next step. NG --> See step 4 OK: Go to next step
3. CHECK WIRE HARNESS BETWEEN A ECU AND B ECU Disconnect the B ECU connector and check for DTCs B1214 and B1215. OK Neither DTC B1214 nor DTC B1215 is output. NOTE: Reconnect the connector before starting the next check. HINT: If the result is as specified, the wire harness between the A ECU and B ECU is functioning normally but the disconnected B ECU is malfunctioning. NG --> REPAIR OR REPLACE WIRE HARNESS BETWEEN A ECU AND B ECU OK --> REPLACE B ECU
4. CHECK DIAGNOSTIC TROUBLE CODE (C ECU) Disconnect the B ECU and C ECU connectors and check for DTCs B1214 and B1215. OK Neither DTC B1214 nor DTC B1215 is output. NOTE: Disconnect the connectors one by one. Reconnect the connectors before starting the next check. HINT: The C ECU in the door system bus represents the windshield wiper switch. If the result is as specified, the disconnected C ECU (windshield wiper switch) or the wire harness between the B ECU and C ECU is malfunctioning. NG --> See step 6 OK: Go to next step
5. CHECK WIRE HARNESS BETWEEN B ECU AND C ECU Disconnect the C ECU connector and check for DTCs B1214 and B1215. OK Neither DTC B1214 nor DTC B1215 is output. NOTE: Reconnect the connector before starting the next check. HINT: If the result is as specified, the wire harness between the B ECU and C ECU is functioning normally but the disconnected C ECU is malfunctioning. NG --> REPAIR OR REPLACE WIRE HARNESS BETWEEN B ECU AND C ECU OK --> REPLACE C ECU
6. CHECK WIRE HARNESS BETWEEN NETWORK GATEWAY ECU AND A ECU OR C ECU Check for a short circuit in B+ or body ground. Disconnect the A ECU, C ECU and multiplex network gateway ECU connectors. Measure the voltage and resistance of the wire harness side connectors. Standard voltage Tester Connection Specified Condition A ECU connector/multiplex network gateway ECU connector - Body ground Below 1 V C ECU connector/multiplex network gateway ECU connector - Body ground Below 1 V Standard resistance Tester Connection Specified Condition A ECU connector/multiplex network gateway ECU connector - Body ground 10 kohms or higher C ECU connector/multiplex network gateway ECU connector - Body ground 10 kohms or higher HINT: The A ECU in the door system bus represents the main body ECU RH. The C ECU in the door system bus represents the windshield wiper switch. NG --> REPAIR OR REPLACE WIRE HARNESS BETWEEN NETWORK GATEWAY ECU AND A ECU OR C ECU OK --> REPLACE MULTIPLEX NETWORK GATEWAY ECU

This DTC is detected when the communication between the tire pressure monitor ECU and gateway ECU stops for more than 10 seconds.

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This DTC is detected when communication between the AVC-LAN (radio receiver assembly or multi-display assembly) and multiplex network gateway ECU stops for more than 10 seconds.

1. This DTC is detected when communication between the air conditioning amplifier (A/C ECU) and gateway ECU stops for more than 10 seconds.

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When a +B short circuit or body ground short circuit is detected on the instrument panel system communication bus (BEAN), the instrument panel system communication bus (BEAN) is disabled and a DTC code is output.

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1. CHECK DIAGNOSTIC TROUBLE CODE (A ECU) Disconnect the A ECU connector and check for DTCs B1266 and B1267. OK Neither DTC B1266 nor DTC B1267 is output. NOTE: Reconnect the connector before starting the next check. HINT: The A ECU in the instrument panel system bus represents the air conditioning amplifier. If the result is as specified, the disconnected A ECU (air conditioning amplifier) is malfunctioning. OK --> REPLACE A ECU NG: Go to next step
2. CHECK DIAGNOSTIC TROUBLE CODE (B ECU) Disconnect the A ECU and B ECU connectors and check for DTCs B1266 and B1267. OK Neither DTC B1266 nor DTC B1267 is output. NOTE: Disconnect the connectors one by one. Reconnect the connectors before starting the next check. HINT: Remove the B ECUs in the following order: AFS ECU Clearance warning ECU Combination meter ECU If the result is as specified, the disconnected B ECU (one of the ECUs from the above list) or the wire harness between the A ECU and B ECU is malfunctioning. After the DTC is cleared, proceed to the next step. NG --> See step 4 OK: Go to next step
3. CHECK WIRE HARNESS BETWEEN A ECU AND B ECU Disconnect the B ECU connector and check for DTCs B1266 and B1267. OK Neither DTC B1266 nor DTC B1267 is output. NOTE: Reconnect the connector before starting the next check. HINT: If the result is as specified, the wire harness between the A ECU and B ECU is functioning normally but the disconnected B ECU is malfunctioning. NG --> REPAIR OR REPLACE WIRE HARNESS BETWEEN A ECU AND B ECU OK --> REPLACE B ECU
4. CHECK DIAGNOSTIC TROUBLE CODE (C ECU) Disconnect the B ECU and C ECU connectors and check for DTCs B1266 and B1267. OK Neither DTC B1266 nor DTC B1267 is output. NOTE: Disconnect the connectors one by one. Reconnect the connectors before starting the next check. HINT: The C ECU in the instrument panel system bus represents the tire pressure warning ECU. If the result is as specified, the disconnected C ECU (tire pressure warning ECU) or the wire harness between the B ECU and C ECU is malfunctioning. NG --> See step 6 OK: Go to next step
5. CHECK WIRE HARNESS BETWEEN B ECU AND C ECU Disconnect the C ECU connector and check for DTCs B1266 and B1267. OK Neither DTC B1266 nor DTC B1267 is output. NOTE: Reconnect the connector before starting the next check. HINT: If the result is as specified, the wire harness between the B ECU and C ECU is functioning normally but the disconnected C ECU is malfunctioning. NG --> REPAIR OR REPLACE WIRE HARNESS BETWEEN B ECU AND C ECU OK --> REPLACE C ECU
6. CHECK WIRE HARNESS BETWEEN GATEWAY ECU AND A ECU OR C ECU Check for a short-circuit in B+ or body ground. Disconnect the A ECU, C ECU and multiplex network gateway ECU connectors. Measure the resistance and voltage of the wire harness side connectors. Standard voltage Tester Connection Specified Condition A ECU connector/multiplex network gateway ECU connector - Body ground Below 1 V C ECU connector/multiplex network gateway ECU connector - Body ground Below 1 V Standard resistance Tester Connection Specified Condition A ECU connector/multiplex network gateway ECU connector - Body ground 10 kohms or higher C ECU connector/multiplex network gateway ECU connector - Body ground 10 kohms or higher HINT: The A ECU in the instrument panel system bus represents the air conditioning amplifier. The C ECU in the instrument panel system bus represents the tire pressure monitor ECU. NG --> REPAIR OR REPLACE WIRE HARNESS BETWEEN GATEWAY ECU AND A ECU OR C ECU OK --> REPLACE MULTIPLEX NETWORK GATEWAY ECU

This DTC is detected when communication between the combination meter ECU and multiplex network gateway ECU stops for more than 10 seconds.

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This DTC is detected when communication between the position control ECU and switch (driver seat ECU) and multiplex network gateway ECU stops for more than 10 seconds.

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This DTC is detected when communication between the sliding roof control ECU and network gateway ECU stops for more than 10 seconds.

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This DTC is detected when communication between the combination switch (windshield wiper switch) and network gateway ECU stops for more than 10 seconds.

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This DTC is detected when communication between the rain sensor and multiplex network gateway ECU stops for more than 10 seconds.

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This DTC is detected when communication between the main body ECU LH (cowl side J/B LH) and network gateway ECU stops for more than 10 seconds.

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SYSTEM DESCRIPTION

This DTC is detected when communication between the position control ECU and switch (passenger ECU) and network gateway ECU stops for more than 10 seconds.

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This DTC is detected when communication between the front controller and gateway ECU stops for more than 10 seconds.

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This DTC is detected when communication between the clearance warning ECU and gateway ECU stops for more than 10 seconds.

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