Lexus IS250 IS220d GSE20 ALE20 2AD-FHV STARTING
ENTRY AND START SYSTEM - TERMINALS OF ECU
| CHECK POWER SOURCE CONTROL ECU |
Disconnect the J55 ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| AM1 (J55-33) - Body ground | O - Body ground | +B power supply | Always | 10 to 14 V |
| AM2 (J55-12) - Body ground | O - Body ground | +B power supply | Always | 10 to 14 V |
| SSW1 (J55-14) - Body ground | B - Body ground | Engine switch signal | Engine switch pushed | Below 1 Ω |
| SSW1 (J55-14) - Body ground | B - Body ground | Engine switch signal | Engine switch not pushed | 10 kΩ or higher |
| SSW2 (J55-37) - Body ground | SB - Body ground | Engine switch signal | Engine switch pushed | Below 1 Ω |
| SSW2 (J55-37) - Body ground | SB - Body ground | Engine switch signal | Engine switch not pushed | 10 kΩ or higher |
| GND2 (J55-6) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| LIN1 (J55-30) - Body ground | V - Body ground | LIN line | Always | 10 kΩ or higher |
| 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 |
If the result is not as specified, there may be a malfunction on the wire harness side.
Reconnect the J55 ECU connector.
Measure the voltage of the connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| ACCD (J55-11) - GND2 (J55-6) | LG - W-B | ACC signal | Engine switch on (ACC) | Output voltage at terminal AM2 is -2 V or more. |
| ACCD (J55-11) - GND2 (J55-6) | LG - W-B | ACC signal | Engine switch off | Below 1 V |
| IG1D (J55-34) - GND2 (J55-6) | P - W-B | IG1 signal | Engine switch on (IG) | Output voltage at terminal AM2 is -2 V or more. |
| IG1D (J55-34) - GND2 (J55-6) | P - W-B | IG1 signal | Engine switch on (ACC) | Below 1 V |
| IG2D (J55-35) - GND2 (J55-6) | LG - W-B | IG2 signal | Engine switch on (IG) | Output voltage at terminal AM2 is -2 V or more. |
| IG2D (J55-35) - GND2 (J55-6) | LG - W-B | IG2 signal | Engine switch on (ACC) | Below 1 V |
| SLR+ (J55-32) - GND2 (J55-6) | W - W-B | Steering lock motor signal | Steering lock motor operating | Below 1 V |
| SLR+ (J55-32) - GND2 (J55-6) | W - W-B | Steering lock motor signal | Steering lock motor does not operate | Output voltage at terminal AM2 is -2 V or more. |
| SLP (J55-26) - GND2 (J55-6) | R - W-B | Steering lock actuator position signal | Steering lock is locked | Pulse generation (See waveform 3) |
| SLP (J55-26) - GND2 (J55-6) | R - W-B | Steering lock actuator position signal | Steering lock is released | Pulse generation (See waveform 3) |
| SPD (J55-19) - GND2 (J55-6) | P - W-B | Vehicle speed signal | Engine switch on (IG), rotate rear wheel slowly | Pulse generation (See waveform 1) |
| TACH (J55-2) - GND2 (J55-6) | W - W-B | Tachometer signal | Engine running | Pulse generation (See waveform 2) |
| CTSW (J55-31) - GND2 (J55-6) | LG - W-B | Starter assist signal | Engine switch is pushed once → on (IG) | 0.1 to 0.8 V *1
→ Output voltage at terminal AM2 is -2 V or more. |
| STSW (J55-39) - GND2 (J55-6) | L - W-B | Starter activation request signal | Clutch pedal depressed, engine switch hold on (ST) | Output voltage at terminal AM2 is -2 V or more. |
| STR1 (J55-17) - GND2 (J55-6) | SB - W-B | Clutch position switch | Clutch pedal depressed | Below 1 V |
| STR2 (J55-15) - GND2 (J55-6) | V - W-B | Starter signal | Clutch pedal depressed, engine switch on (ST) | Output voltage at terminal AM2 is -2 V or more. *2 |
| INDS (J55-4) - GND2 (J55-6) | L - W-B | Vehicle condition signal | Clutch pedal depressed. | Output voltage at terminal AM2 is -2 V or more. |
| INDW (J55-13) - GND2 (J55-6) | BR - W-B | Warning signal | Clutch pedal not depressed, engine switch on (ACC, IG) | Output voltage at terminal AM2 is -2 V or more. |
| SWIL (J55-36) - GND2 (J55-6) | Y - W-B | Illumination signal | Light control switch TAIL or HEAD | Output voltage at terminal AM2 is -2 V or more. |
- HINT:
- *1: Voltage is output only when the engine is cranking.
- *2: Voltage is output for 0.3 seconds when engine is cranking start. Disconnect the A49 connector from the ECM before measuring the voltage.
If the result is not as specified, the ECU may have a malfunction.
Using an oscilloscope, check the signal waveform of the ECU.
Waveform 1
| Terminal No. | J55-19 - Body ground |
| Tool Setting | 5 V/DIV., 10 ms./DIV. |
| Vehicle Condition | Driving at approx. 20 km/h (12 mph) |
- HINT:
- As the vehicle speed increases, the wavelength shortens.
Waveform 2
| Terminal No. | J55-2 - Body ground |
| Tool Setting | 5 V/DIV., 10 ms./DIV. |
| Vehicle Condition | Engine idling |
- HINT:
- As the engine revolution speed increases, the wavelength shortens.
Waveform 3
| Terminal No. | J55-26 - Body ground |
| Tool Setting | 2 V/DIV., 100 ms./DIV. |
| Vehicle Condition | Steering lock / unlock |
| CHECK CERTIFICATION ECU |
Disconnect the P33 ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| +B1 (P33-1) - Body ground | L - Body ground | +B power supply | Always | 10 to 14 V |
| IG (P33-18) - Body ground | B - Body ground | Ignition power supply | Engine switch on (IG) | 10 to 14 V |
| IG (P33-18) - Body ground | B - Body ground | Ignition power supply | Engine switch off | Below 1 V |
| LIN (P33-10) - Body ground | V - Body ground | LIN line | Always | 10 kΩ or higher |
| E (P33-17) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK ECM |
Disconnect the A49 and E59 ECM connectors.
Measure the voltage and resistance of the wire harness side connectors.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| +B (A49-1) - Body ground | B-R - Body ground | Power source of ECM | Engine switch on (IG) | 10 to 14 V |
| IGSW (A49-25) - Body ground | B-W - Body ground | Ignition switch signal | Engine switch on (IG) | 10 to 14 V |
| E01 (E59-45) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| E02 (E59-44) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| E05 (E59-46) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| E1 (E59-109) - Body ground | BR - Body ground | Ground | Always | Below 1 Ω |
If the result is not as specified, there may be a malfunction on the wire harness side.
Reconnect the A49 and E59 ECM connectors.
Measure the voltage of the connectors.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| STA (A49-43) - E1 (E59-109) | R - BR | Starter relay operation signal | Cranking | 10 to 14 V |
| ACCR (A49-24) - E1 (E59-109) | W-L - BR | ACC relay cut signal (output) | Engine switch on (IG) | 10 to 14 V |
| TACH (A49-13) - E1 (E59-109) | R-W - BR | Engine revolution signal (output) | Idling | Pulse generation (See waveform 1) |
| STAR (E59-53) - E1 (E59-109) | L - BR | Clutch start switch signal (input) | Engine switch on (IG), clutch pedal depressed | 10 to 14 V |
If the result is not as specified, the ECM may have a malfunction.
Using an oscilloscope, check the signal waveform of the ECM.
| Terminal No. | A49-13 - E59-109 |
| Tool Setting | 5 V/DIV., 10 ms./DIV. |
| Vehicle Condition | Engine idling |
- HINT:
- As the vehicle speed increases, the wavelength shortens.
| CHECK STEERING LOCK ECU |
Disconnect the J29 ECU connector.
Measure the voltage and resistance of the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| B (J29-7) - Body ground | O - Body ground | +B power supply | Always | 10 to 14 V |
| IG2 (J29-6) - Body ground | LG - Body ground | Ignition power supply | Engine switch on (IG) | 10 to 14 V |
| IG2 (J29-6) - Body ground | LG - Body ground | Ignition power supply | Engine switch off | Below 1 V |
| GND (J29-1) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| SGND (J29-2) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
If the result is not as specified, there may be a malfunction on the wire harness side.
Reconnect the J29 ECU connector.
Measure the voltage of the connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| SLP1 (J29-4) - GND (J29-1) | R - W-B | Steering lock actuator position signal | Steering is locked | 10 to 14 V |
| SLP1 (J29-4) - GND (J29-1) | R - W-B | Steering lock actuator position signal | Steering is released | Below 1 V |
If the result is not as specified, the ECU may have a malfunction.
LEXUS IS250, IS220d / GSE20 ALE20