Lexus IS250 IS220d GSE20 ALE20 - ENGINE IMMOBILISER
ENGINE IMMOBILISER SYSTEM (for 4GR-FSE) - TERMINALS OF ECU
| CHECK ENGINE SWITCH |
Disconnect the J31 switch connector.
Measure the resistance of the wire harness.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| AGND (J31-8) - Body ground | GR - 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 J31 switch connector.
Measure the resistance and voltage at the connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| AGND (J31-8) - Body ground | GR - Body ground | Ground | Always | Below 1 Ω |
| VC5 (J31-14) - AGND (J31-8) | R - GR | Power supply | Key is not in cabin | Below 1 V |
| VC5 (J31-14) - AGND (J31-8) | R - GR | Power supply | Press engine switch | 4.6 to 5.4 V |
| CODE (J31-10) - AGND (J31-8) | SB - GR | Demodulated signal of key code data | Key is not in cabin | Below 1 V |
| CODE (J31-10) - AGND (J31-8) | SB - GR | Demodulated signal of key code data | Press engine switch and hold key close to engine switch* | Pulse generation (see waveform 1) |
| TXCT (J31-9) - AGND (J31-8) | L - GR | Key code output signal | Key is not in cabin | Below 1 V |
| TXCT (J31-9) - AGND (J31-8) | L - GR | Key code output signal | Press engine switch and hold key close to engine switch* | Pulse generation (see waveform 2) |
- HINT:
- *: Remove the key battery before performing this inspection.
If the result is not as specified, the switch may have a malfunction.
Inspect using an oscilloscope.
Waveform 1 (Reference)
| Item | Content |
| Symbols (Terminal No.) | CODE (J31-10) - AGND (J31-8) |
| Tool Setting | 2 V/DIV., 20 msec./DIV. |
| Condition | Press engine switch and hold key close to engine switch* |
- HINT:
- *: Remove the key battery before performing this inspection.
Waveform 2 (Reference)
| Item | Content |
| Symbols (Terminal No.) | TXCT (J31-9) - AGND (J31-8) |
| Tool Setting | 2 V/DIV., 20 msec./DIV. |
| Condition | Press engine switch and hold key close to engine switch* |
- HINT:
- *: Remove the key battery before performing this inspection.
| CHECK CERTIFICATION ECU |
Disconnect the P33 ECU connector.
Measure the resistance and voltage at the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| E (P33-17) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| +B1 (P33-1) - E (P33-17) | L - W-B | +B power supply | Always | 10 to 14 V |
| IG (P33-18) - E (P33-17) | B - W-B | Ignition power supply | Engine switch off | Below 1 V |
If the result is not as specified, there may be a malfunction on the wire harness side.
Reconnect the P33 ECU connector.
Measure the resistance and voltage of the connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| AGND (P33-40) - Body ground | LG - Body ground | Engine switch ground | Always | Below 1 Ω |
| VC5 (P33-30) - AGND (P33-40) | L - LG | Engine switch power supply | Key is not in cabin | Below 1 V |
| VC5 (P33-30) - AGND (P33-40) | L - LG | Engine switch power supply | Press engine switch | 4.6 to 5.4 V |
| CODE (P33-9) - AGND (P33-40) | GR - LG | Engine switch CODE input | Key is not in cabin | Below 1 V |
| CODE (P33-9) - AGND (P33-40) | GR - LG | Engine switch CODE input | Press engine switch and hold key close to engine switch* | Pulse generation (see waveform 1) |
| TXCT (P33-8) - AGND (P33-40) | G - LG | Engine switch TX output | Key is not in cabin | Below 1 V |
| TXCT (P33-8) - AGND (P33-40) | G - LG | Engine switch TX output | Press engine switch and hold key close to engine switch* | Pulse generation (see waveform 2) |
- HINT:
- *: Remove the key battery before performing this inspection.
If the result is not as specified, the ECU may have a malfunction.
Inspect using an oscilloscope.
Waveform 1 (Reference)
| Item | Content |
| Symbols (Terminal No.) | CODE (P33-9) - AGND (P33-40) |
| Tool Setting | 2 V/DIV., 20 msec./DIV. |
| Condition | Press engine switch and hold key close to engine switch* |
- HINT:
- *: Remove the key battery before performing this inspection.
Waveform 2 (Reference)
| Item | Content |
| Symbols (Terminal No.) | TXCT (P33-8) - AGND (P33-40) |
| Tool Setting | 2 V/DIV., 20 msec./DIV. |
| Condition | Press engine switch and hold key close to engine switch* |
- HINT:
- *: Remove the key battery before performing this inspection.
| CHECK ID CODE BOX |
Disconnect the J69 ECU connector.
Measure the resistance and voltage at the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| GND (J69-8) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| +B (J69-1) - GND (J69-8) | G - W-B | +B power supply | Always | 10 to 14 V |
If the result is not as specified, there may be a malfunction on the wire harness side.
Reconnect the J69 ECU connector.
Measure the voltage of the connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| EFII (J69-5) - GND (J69-8) | W - W-B | ECM input signal | Engine switch off | Below 1 V |
| EFII (J69-5) - GND (J69-8) | W - W-B | ECM input signal | Engine switch on (IG) | Pulse generation (see waveform 1) |
| EFIO (J69-6) - GND (J69-8) | P - W-B | ECM output signal | Engine switch off | Below 1 V |
| EFIO (J69-6) - GND (J69-8) | P - W-B | ECM output signal | Engine switch on (IG) | Pulse generation (see waveform 2) |
If the result is not as specified, the ECU may have a malfunction.
Inspect using an oscilloscope.
Waveform 1 (Reference)
| Item | Content |
| Symbols (Terminal No.) | EFII (J69-5) - GND (J69-8) |
| Tool Setting | 10 V/DIV., 100 msec./DIV. |
| Condition | Engine switch on (IG) |
Waveform 2 (Reference)
| Item | Content |
| Symbols (Terminal No.) | EFIO (J69-6) - GND (J69-8) |
| Tool Setting | 10 V/DIV., 100 msec./DIV. |
| Condition | Engine switch on (IG) |
| CHECK POWER SOURCE CONTROL ECU |
Disconnect the J55 ECU connector.
Measure the resistance and voltage at the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| GND2 (J55-6) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| AM2 (J55-12) - Body ground | O - Body ground | +B power supply | Always | 10 to 14 V |
| AM1 (J55-33) - Body ground | O - Body ground | +B power supply | Always | 10 to 14 V |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK STEERING CONTROL ECU |
Disconnect the J29 ECU connector.
Measure the resistance and voltage at the wire harness side connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| SGND (J29-2) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| GND (J29-1) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| 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 off | Below 1 V |
| IG2 (J29-6) - Body ground | LG - Body ground | Ignition power supply | Engine switch on (IG) | 10 to 14 V |
If the result is not as specified, there may be a malfunction on the wire harness side.
| CHECK ECM |
Measure the resistance and voltage of the connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| E1 (E4-7) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| E01 (E5-2) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| E02 (E5-1) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| E03 (E3-6) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| E04 (E6-5) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| E05 (E6-3) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| EC (A5-2) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| ME01 (E3-4) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| BATT (A5-4) - E1 (E4-7) | L - BR | Battery (for measuring battery voltage and for ECM memory) | Always | 10 to 14 V |
| +B (A5-6) - E1 (E4-7) | B-R - BR | Power source of ECM | Engine switch off | Below 1 V |
| +B (A5-6) - E1 (E4-7) | B-R - BR | Power source of ECM | Engine switch on (IG) | 10 to 14 V |
| +B1 (A5-5) - E1 (E4-7) | B-R - BR | Power source of ECM | Engine switch off | Below 1 V |
| +B1 (A5-5) - E1 (E4-7) | B-R - BR | Power source of ECM | Engine switch on (IG) | 10 to 14 V |
| IMI (A6-6) - E1 (E4-7) | LG - BR | Immobiliser code ECU input signal | Engine switch off | Below 1 V |
| IMI (A6-6) - E1 (E4-7) | LG - BR | Immobiliser code ECU input signal | Engine switch on (IG) | Pulse generation (see waveform 1) |
| IMO (A6-7) - E1 (E4-7) | W-R - BR | Immobiliser code ECU output signal | Engine switch off | Below 1 V |
| IMO (A6-7) - E1 (E4-7) | W-R - BR | Immobiliser code ECU output signal | Engine switch on (IG) | Pulse generation (see waveform 2) |
If the result is not as specified, the ECM may have a malfunction.
Inspect using an oscilloscope.
Waveform 1 (Reference)
| Item | Content |
| Symbols (Terminal No.) | IMI (A6-6) - E1 (E4-7) |
| Tool Setting | 10 V/DIV., 100 msec./DIV. |
| Condition | Engine switch on (IG) |
Waveform 2 (Reference)
| Item | Content |
| Symbols (Terminal No.) | IMO (A6-7) - E1 (E4-7) |
| Tool Setting | 10 V/DIV., 100 msec./DIV. |
| Condition | Engine switch on (IG) |
| CHECK MAIN BODY ECU RH (COWL SIDE J/B RH) |
Disconnect the RD and RM junction block connectors.
Measure the resistance and voltage at the wire harness side connectors.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| GND2 (RD-7) - Body ground | W-B - Body ground | Ground | Always | Below 1 Ω |
| IG (RM-1) - Body ground | B - Body ground | Ignition power supply | Engine switch off | Below 1 V |
| IG (RM-1) - Body ground | B - Body ground | Ignition power supply | Engine switch on (IG) | 10 to 14 V |
If the result is not as specified, there may be a malfunction on the wire harness side.
Reconnect the RD and RM junction block connectors.
Measure the voltage of the connector.
| Symbols (Terminal No.) | Wiring Color | Terminal Description | Condition | Specified Condition |
| IND (J74-24) - Body ground | LG - Body ground | Indicator light signal | Key is not in cabin (immobiliser system is not set) | Alternating between 10 to 14 V (0.2 seconds) and below 1 V |
If the result is not as specified, the main body ECU RH (cowl side J/B RH) may have a malfunction.