LIN Communication System (Diagnostics - Introduction): Other Lexus IS III

PRECAUTION [04/2013 - ]

1. PRECAUTION FOR DISCONNECTING CABLE FROM NEGATIVE BATTERY TERMINAL NOTE: When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the cable is reconnected. System Name See Procedure Variable Gear Ratio Steering System Refer to «INITIALIZATION [04/2013 - ]»(ref-665529-S01115916402014102400000) Air Conditioning System

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1. DOOR BUS LINES
2. CERTIFICATION BUS LINES

CAUTION / NOTICE / HINT

HINT

1. Use the following procedure to troubleshoot the LIN communication system.
2. *: Use the Techstream.

PROCEDURE

1. VEHICLE BROUGHT TO WORKSHOP Result Proceed to NEXT Result: 1 NEXT See step 2
2. CUSTOMER PROBLEM ANALYSIS HINT: In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred. Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases. The following 5 items are important points for problem analysis: What Vehicle model, system name When Date, time, occurrence frequency Where Road conditions Under what conditions? Driving conditions, weather conditions How did it happen? Problem symptoms Result Proceed to NEXT Result: 1 NEXT See step 3
3. PRE-CHECK Measure the battery voltage. Standard Voltage 11 to 14 V If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step. Check the fuses and relays. Check the connector connections and terminals to make sure that there are no abnormalities such as loose connections, deformation, etc. Result Proceed to NEXT Result: 1 NEXT See step 4
4. INSPECT COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM* Using the Techstream, check for CAN communication system DTCs. Refer to «DIAGNOSIS SYSTEM [04/2013 - ]»(ref-665810-S14264089842014102400000) Result Result Proceed to CAN DTCs are not output A CAN DTCs are output B Result: 2 B GO TO CAN COMMUNICATION SYSTEM. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - ]»(ref-665785-S15342612202014102400000) Result: 1 A See step 5
5. INSPECT COMMUNICATION FUNCTION OF LIN COMMUNICATION SYSTEM* Using the Techstream, check for LIN communication system DTCs. Refer to «DTC CHECK/CLEAR [04/2013 - ]»(ref-665832-S32731231342014102400000) Result Result Proceed to LIN DTCs are not output A LIN DTCs are output B Result: 2 B GO TO DIAGNOSTIC TROUBLE CODE TABLE. Refer to «DIAGNOSTIC TROUBLE CODE TABLE [04/2013 - ]»(ref-665832-S18209437292014102400000) Result: 1 A See step 6
6. OVERALL ANALYSIS AND TROUBLESHOOTING* Terminals of ECU Refer to «TERMINALS OF ECU [04/2013 - ]»(ref-665832-S07958795222014102400000) Data List/Active Test Refer to «DATA LIST/ACTIVE TEST [04/2013 - ]»(ref-665832-S06549687292014102400000) Result Proceed to NEXT Result: 1 NEXT See step 7
7. REPAIR OR REPLACE Result Proceed to NEXT Result: 1 NEXT See step 8
8. CONFIRMATION TEST Result Proceed to NEXT Result: 1 NEXT END

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1. CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY AND MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Disconnect the MB main body ECU (multiplex network body ECU) connector. *A Main Body ECU (Multiplex Network Body ECU) with 3 Connectors *1 Main Body ECU (Multiplex Network Body ECU) *a 3 Connectors *A Main Body ECU (Multiplex Network Body ECU) with 2 Connectors - - *1 Main Body ECU (Multiplex Network Body ECU) - - *a 2 Connectors - - Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connectors disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition MB-11 (GND1) - Body ground - Ground Always Below 1 ohms MB-31 (BECU) - Body ground - Battery power supply Always 11 to 14 V MB-30 (ACC) - Body ground - ACC power supply Engine switch on (ACC) 11 to 14 V MB-30 (ACC) - Body ground - ACC power supply Engine switch off Below 1 V MB-32 (IG) - Body ground - IG power supply Engine switch on (IG) 11 to 14 V MB-32 (IG) - Body ground - IG power supply Engine switch off Below 1 V If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the MB main body ECU (multiplex network body ECU) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition 4B-21 - Body ground P - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the main body ECU (multiplex network body ECU) or instrument panel junction block assembly may be malfunctioning.
2. CHECK POWER WINDOW REGULATOR MOTOR ASSEMBLY (for Driver Door) Disconnect the N17 power window regulator motor assembly (for driver door) connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition N17-2 (B) - Body ground G - Body ground Battery power supply Always 11 to 14 V N17-1 (GND) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the N17 power window regulator motor assembly (for driver door) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition N17-9 (LIN) - Body ground P - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the power window regulator motor assembly (for driver door) may be malfunctioning.
3. CHECK POWER WINDOW REGULATOR MOTOR ASSEMBLY (for Front Passenger Door) Disconnect the N2 power window regulator motor assembly (for front passenger door) connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition N2-2 (B) - Body ground Y - Body ground Battery power supply Always 11 to 14 V N2-1 (GND) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the N2 power window regulator motor assembly (for front passenger door) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition N2-9 (LIN) - Body ground P - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the power window regulator motor assembly (for front passenger door) may be malfunctioning.
4. CHECK POWER WINDOW REGULATOR MOTOR ASSEMBLY (for Rear RH Door) Disconnect the O2 power window regulator motor assembly (for rear RH door) connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition O2-2 (B) - Body ground R - Body ground Battery power supply Always 11 to 14 V O2-1 (GND) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the O2 power window regulator motor assembly (for rear RH door) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition O2-9 (LIN) - Body ground P - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the power window regulator motor assembly (for rear RH door) may be malfunctioning.
5. CHECK POWER WINDOW REGULATOR MOTOR ASSEMBLY (for Rear LH Door) Disconnect the O7 power window regulator motor assembly (for rear LH door) connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition O7-2 (B) - Body ground B - Body ground Battery power supply Always 11 to 14 V O7-1 (GND) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the O7 power window regulator motor assembly (for rear LH door) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition O7-9 (LIN) - Body ground P - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the power window regulator motor assembly (for rear LH door) may be malfunctioning.
6. CHECK MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY (w/o Seat Position Memory System) Disconnect the N27 multiplex network master switch assembly connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition N27-21 (B) - Body ground LG - Body ground Battery power supply Always 11 to 14 V N27-17 (GND) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the N27 multiplex network master switch assembly connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition N27-7 (LIN1) - Body ground P - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the multiplex network master switch assembly may be malfunctioning.
7. CHECK MULTIPLEX NETWORK MASTER SWITCH ASSEMBLY (w/ Seat Position Memory System) Disconnect the N18 multiplex network master switch assembly connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition N18-11 (B) - Body ground LG - Body ground Battery power supply Always 11 to 14 V N18-12 (GND) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the N18 multiplex network master switch assembly connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition N18-17 (LIN1) - Body ground P - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the multiplex network master switch assembly may be malfunctioning.
8. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Disconnect the K6 certification ECU (smart key ECU assembly) connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition K6-11 (E) - Body ground BR - Body ground Ground Always Below 1 ohms K6-10 (+B) - Body ground BE - Body ground +B power supply Always 11 to 14 V If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the K6 certification ECU (smart key ECU assembly) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition K6-6 (LIN) - Body ground V - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the certification ECU (smart key ECU assembly) may be malfunctioning.
9. CHECK STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY) Disconnect the K28 steering lock ECU (steering lock actuator assembly) connector. Measure the resistance and voltage according to the value(s) in the table below. Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition K28-1 (GND) - Body ground W-B Body ground Ground Always Below 1 ohms K28-7 (B) - Body ground G - Body ground Battery power supply Always 11 to 14 V If the result is not as specified, there may be a malfunction on the wire harness side. Reconnect the K28 steering lock ECU (steering lock actuator assembly) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition K28-5 (LIN) - Body ground V - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the steering lock ECU (steering lock actuator assembly) may be malfunctioning.
10. CHECK ID CODE BOX (IMMOBILIZER CODE ECU) Disconnect the K83 ID code box (immobilizer code ECU) connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition K83-5 (GND) - Body ground BR - Body ground Ground Always Below 1 ohms K83-1 (+B) - Body ground G - Body ground +B power supply Always 11 to 14 V If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the K83 ID code box (immobilizer code ECU) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition K83-2 (LIN1) - Body ground V - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the ID code box (immobilizer code ECU) may be malfunctioning.
11. CHECK SLIDING ROOF ECU (SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY) (w/ Sliding Roof System) Disconnect the S5 sliding roof ECU (sliding roof drive gear sub-assembly) connector. Measure the voltage and resistance according to the value(s) in the table below. HINT: Measure the values on the wire harness side with the connector disconnected. Tester Connection Wiring Color Terminal Description Condition Specified Condition S5-8 (B) - Body ground V - Body ground Battery power supply Always 11 to 14 V S5-12 (E) - Body ground W-B - Body ground Ground Always Below 1 ohms If the result is not as specified, there may be a malfunction in the wire harness. Reconnect the S5 sliding roof ECU (sliding roof drive gear sub-assembly) connector. Check for pulses according to the value(s) in the table below. Tester Connection Wiring Color Terminal Description Condition Specified Condition S5-11 (MPX1) - Body ground P - Body ground LIN communication line Engine switch on (IG) Pulse generation If the result is not as specified, the sliding roof ECU (sliding roof drive gear sub-assembly) may be malfunctioning.