Lexus IS250 IS220d GSE20 ALE20 - MULTIPLEX COMMUNICATION
MULTIPLEX COMMUNICATION SYSTEM - TERMINALS OF ECU
| CHECK GATEWAY ECU |
Disconnect the gateway ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (J76-1) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (J76-1) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| ACC (J76-2) - Body ground | O - Body ground | Power source (ACC) | Engine switch: off | Below 1 V |
| ACC (J76-2) - Body ground | O - Body ground | Power source (ACC) | Engine switch: on (IG) | 10 to 14 V |
| BATT (J76-10) - Body ground | LG - Body ground | Power source (+B) | Always | 10 to 14 V |
| MPI1 (J76-4) - Body ground | BR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPI2 (J76-13) - Body ground | BR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPD1 (J76-3) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPD2 (J76-12) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| GND (J76-24) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK MAIN BODY ECU LH (COWL SIDE J/B LH) |
Disconnect the main body ECU LH (cowl side J/B LH) connectors.
Measure the voltage and resistance of the wire harness side connectors.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (LK-6) - Body ground | Y - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (LK-6) - Body ground | Y - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| BKUP (LJ-23) - Body ground | Y - Body ground | Power source (+B) | Always | 10 to 14 V |
| MPXB (LD-18) - Body ground | LG - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (LD-3) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| SGND (LD-8) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| SGND (LD-9) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (Q3-15) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX2 (A30-17) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK MAIN BODY ECU RH (COWL SIDE J/B RH) |
Disconnect the main body ECU RH (cowl side J/B RH) connectors.
Measure the voltage and resistance of the wire harness side connectors.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (RM-1) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (RM-1) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
|
*1ACC (RD-27) - Body ground *2ACC (RJ-22) - Body ground | O - Body ground | Power source (ACC) | Engine switch: off | Below 1 V |
|
*1ACC (RD-27) - Body ground *2ACC (RJ-22) - Body ground | O - Body ground | Power source (ACC) | Engine switch: on (ACC) | 10 to 14 V |
| ALTB (RA-15) - Body ground | SB - Body ground | Power source (+B) | Always | 10 to 14 V |
| BECU (RK-5) - Body ground | G-R - Body ground | Power source (+B) | Always | 10 to 14 V |
| BATB (RN-1) - Body ground | R - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND2 (RD-11) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| GND2 (RD-7) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| GND2 (RA-4) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| GND2 (RA-5) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| GND1 (RD-17) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX5 (P1-5) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX6 (J75-20) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX4 (J75-19) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX1 (RA-20) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX1 (RJ-21) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX2 (J75-21) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
- HINT:
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK TILT AND TELESCOPIC ECU |
Disconnect the tilt and telescopic ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (J28-8) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (J28-8) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| ECUB (J28-9) - Body ground | LG - Body ground | Power source (+B) | Always | 10 to 14 V |
| +B (J28-2) - Body ground | SB - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (J28-11) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (J28-5) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK POWER WINDOW MASTER SWITCH |
Disconnect the power window master switch connector.
Measure the voltage and the resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| SIG (M7-20) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| SIG (M7-20) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| CPUB (M7-9) - Body ground | G - Body ground | Power source (+B) | Always | 10 to 14 V |
| BDR (M7-10) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (M7-2) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (M7-7) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX2 (M7-8) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| SIG (L17-20) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| SIG (L17-20) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| CPUB (L17-9) - Body ground | G - Body ground | Power source (+B) | Always | 10 to 14 V |
| BDR (L17-10) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (L17-2) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (L17-7) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX2 (L17-8) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK OUTER MIRROR CONTROL ECU LH |
Disconnect the outer mirror control ECU LH connector.
Measure the voltage and the resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| SIG (M10-3) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| SIG (M10-3) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| CPUB (M10-4) - Body ground | G - Body ground | Power source (+B) | Always | 10 to 14 V |
| BDR (M10-6) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (M10-1) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (M10-8) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK POWER SEAT CONTROL ECU RH |
Disconnect the power seat control ECU RH connectors.
Measure the voltage and resistance of the wire harness side connectors.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (T7-4) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (T7-4) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| +B (T6-5) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| SYSB (T7-8) - Body ground | P - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (T6-1) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (T7-1) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK CERTIFICATION ECU |
Disconnect the certification ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (P33-18) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (P33-18) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| ACC (P33-19) - Body ground | O - Body ground | Power source (ACC) | Engine switch: off | Below 1 V |
| ACC (P33-19) - Body ground | O - Body ground | Power source (ACC) | Engine switch: on (IG) | 10 to 14 V |
| +B1 (P33-1) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| E (P33-17) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (P33-27) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX2 (P33-28) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK FRONT CONTROLLER |
Disconnect the front controller connectors.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| 2E-3 - Body ground | B-Y - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| 2E-3 - Body ground | B-Y - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| 2E-4 - Body ground | G-R - Body ground | Power source (+B) | Always | 10 to 14 V |
| 2F-1 - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| 2F-6 - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| 2F-5 - Body ground | L - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK OUTER MIRROR CONTROL ECU RH |
Disconnect the outer mirror control ECU RH connector.
Measure the voltage and the resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| SIG (L10-3) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| SIG (L10-3) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| CPUB (L10-4) - Body ground | G - Body ground | Power source (+B) | Always | 10 to 14 V |
| BDR (L10-6) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (L10-1) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (L10-8) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK POWER SEAT CONTROL ECU LH |
Disconnect the power seat control ECU LH connectors.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (U7-4) - Body ground | Y - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (U7-4) - Body ground | Y - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| +B (U6-5) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| SYSB (U7-8) - Body ground | LG - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (U6-1) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (U7-1) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK SLIDING ROOF CONTROL ECU |
Disconnect the sliding roof control ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (R6-6) - Body ground | V - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (R6-6) - Body ground | V - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| B (R6-5) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| E (R6-7) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (R6-10) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK RAIN SENSOR |
Disconnect the rain sensor connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| SIG (R7-1) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| SIG (R7-1) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| MPX (R7-2) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK POWER SOURCE CONTROL ECU |
Disconnect the power source control ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| AM1 (J55-33) - Body ground | O - Body ground | Power source (+B) | Always | 10 to 14 V |
| AM2 (J55-12) - Body ground | O - Body ground | Power source (+B) | Always | 10 to 14 V |
| MPX1 (J55-7) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX2 (J55-24) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
| GND2 (J55-6) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK WINDSHIELD WIPER SWITCH ASSEMBLY |
Disconnect the windshield wiper switch assembly connector.
Measure the resistance and voltage of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (J26-2) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (J26-2) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| B (J26-1) - Body ground | LG - Body ground | Power source (+B) | Always | 10 to 14 V |
| E (J26-5) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (J26-6) - Body ground | GR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK COMBINATION METER ECU |
Disconnect the combination meter ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG+ (J34-12) - Body ground | O - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG+ (J34-12) - Body ground | O - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| B (J34-23) - Body ground | L - Body ground | Power source (+B) | Always | 10 to 14 V |
| B (J34-24) - Body ground | LG - Body ground | Power source (+B) | Always | 10 to 14 V |
| E2 (J34-1) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| ES (J34-13) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX+ (J34-6) - Body ground | BR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX- (J34-18) - Body ground | BR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK CLEARANCE WARNING ECU |
Disconnect the clearance warning ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (Q37-8) - Body ground | Y - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (Q37-8) - Body ground | Y - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| E (Q37-27) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| M+ (Q37-26) - Body ground | BR - Body ground | MPX line | Always | 10 kΩ or higher |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK AFS ECU |
Disconnect the AFS ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG (A27-2) - Body ground | B-O - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG (A27-2) - Body ground | B-O - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| MPX1 (A27-5) - Body ground | BR-R - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX2 (A27-6) - Body ground | BR - Body ground | MPX line | Always | 10 kΩ or higher |
| E1 (A27-1) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK AIR CONDITIONING AMPLIFIER |
Disconnect the air conditioning amplifier connector.
Measure the voltage and the resistance of the wire harness side connector.
| Symbols (Terminals No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IG+ (J58-21) - Body ground | B - Body ground | Power source (IG) | Engine switch: off | Below 1 V |
| IG+ (J58-21) - Body ground | B - Body ground | Power source (IG) | Engine switch: on (IG) | 10 to 14 V |
| B (J58-1) - Body ground | Y - Body ground | Power source (+B) | Always | 10 to 14 V |
| MPX+ (J58-30) - Body ground | BR - Body ground | MPX line | Always | 10 kΩ or higher |
| MPX- (J58-31) - Body ground | BR - Body ground | MPX line | Always | 10 kΩ or higher |
| GND (J58-20) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| CHECK DOUBLE DOOR LOCK ECU |
Measure the voltage and the resistance of the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| +B (P34-1) - Body ground | R - Body ground | Power source (+B) | Always | 10 to 14 V |
| CPUB (P34-7) - Body ground | LG - Body ground | Power source (+B) | Always | 10 to 14 V |
| GND (P34-14) - Body ground | W-B - Body ground | Ground for main power supply | Always | Below 1 Ω |
| MPX1 (P34-9) - Body ground |
*1LG - Body ground *2GR - Body ground | MPX line | Always | 10 kΩ or higher |
- HINT:
If the result is not as specified, there may be a malfunction on the wire harness side.