Lexus ES: Lost Communication with Humidity/Rain Sensor LIN (B1279)
DESCRIPTION
The main body ECU (multiplex network body ECU) and rain sensor communicate via LIN communication. The main body ECU (multiplex network body ECU) stores this DTC if communication becomes abnormal.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory | DTC Output from |
|---|---|---|---|---|---|
| B1279 | Lost Communication with Humidity/Rain Sensor LIN |
|
| ○ | Main Body |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses of circuits related to this system before performing the following procedure.
-
Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
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PROCEDURE
| 1. | CHECK FOR DTC |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Main Body / Trouble Codes.
(e) Check for DTCs.
Body Electrical > Main Body > Trouble Codes| Result | Proceed to |
|---|---|
| Only DTC B1279 is output | A |
| DTC B1279 and B1373 are output | B |
| B | .gif) | GO TO DTC B1373 |
|
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| 2. | CHECK HARNESS AND CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - RAIN SENSOR) |
(a) Disconnect the G36 main body ECU (multiplex network body ECU) connector.
(b) Disconnect the P2 rain sensor connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| G36-3 (LIN3) - P2-3 (MPX) | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 3. | CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| *a | Component without harness connected (Main Body ECU (Multiplex Network Body ECU) |
(a) Check for voltage and pulses according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| G36-3 (LIN3) - Body ground | Engine switch off | Below 1 V |
| Engine switch on (IG) | Pulse generation |
| NG | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
|
| 4. | CHECK HARNESS AND CONNECTOR (POWER SOURCE - RAIN SENSOR) |
| *a | Front view of wire harness connector (to Rain Sensor) |
(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| P2-4 (SIG) - Body ground | Engine switch off | Below 1 V |
| Engine switch on (IG) | 11 to 14 V |
| NG | | GO TO STEP 7 |
|
| 5. | CHECK HARNESS AND CONNECTOR (RAIN SENSOR - BODY GROUND) |
| *a | Front view of wire harness connector (to Rain Sensor) |
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| P2-2 (ES) - Body ground | Always | Below 1 Ω |
| OK | | REPLACE RAIN SENSOR |
|
| 6. | INSPECT MAP LIGHT SUB-ASSEMBLY |
| *a | Component without harness connected (Map Light Sub-assembly) |
(a) Remove the map light sub-assembly.
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(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| P13-19 (GND) - P13-21 (GND2) | Always | Below 1 Ω |
| OK | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
| NG | | REPLACE MAP LIGHT SUB-ASSEMBLY |
| 7. | INSPECT MAP LIGHT SUB-ASSEMBLY |
| *a | Component without harness connected (Map Light Sub-assembly) |
(a) Remove the map light sub-assembly.
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(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| P13-1 (IG) - P13-14 (IG2) | Always | Below 1 Ω |
| OK | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
| NG | | REPLACE MAP LIGHT SUB-ASSEMBLY |
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