Lexus IS250 IS220d GSE20 ALE20 - MULTIPLEX COMMUNICATION
CHECK DIAGNOSTIC TROUBLE CODE (A ECU)
CHECK DIAGNOSTIC TROUBLE CODE (B ECU)
CHECK WIRE HARNESS BETWEEN A ECU AND B ECU
CHECK DIAGNOSTIC TROUBLE CODE (C ECU)
CHECK WIRE HARNESS BETWEEN B ECU AND C ECU
CHECK WIRE HARNESS BETWEEN GATEWAY ECU AND A ECU OR C ECU
DTC B1266 Short to B+ in Instrument Panel System Communication Bus Malfunction
DTC B1267 Short to GND in Instrument Panel System Communication Bus Malfunction
DESCRIPTION
When a +B short circuit or body ground short circuit is detected on the instrument panel system communication bus (BEAN), the instrument panel system communication bus (BEAN) is disabled and a DTC code is output.
| DTC No. | DTC Detection Condition | Trouble Area |
| B1266 | Instrument panel system communication circuit and +B battery system short | Gateway ECU Air conditioning amplifier (A/C ECU) AFS ECU Combination meter ECU Wire harness |
| B1267 | Instrument panel system communication circuit and body ground short | Gateway ECU Air conditioning amplifier (A/C ECU) AFS ECU Combination meter ECU Wire harness |
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.CHECK DIAGNOSTIC TROUBLE CODE (A ECU) |
Disconnect the A ECU connector and check for DTCs B1266 and B1267.
- OK:
- Neither DTC B1266 nor DTC B1267 is output.
- NOTICE:
- Reconnect the connector before starting the next check.
- HINT:
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| OK | |
| 3.CHECK WIRE HARNESS BETWEEN A ECU AND B ECU |
Disconnect the B ECU connector and check for DTCs B1266 and B1267.
- OK:
- Neither DTC B1266 nor DTC B1267 is output.
- NOTICE:
- Reconnect the connector before starting the next check.
- HINT:
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| OK | |
| Go to step 6 |
| 5.CHECK WIRE HARNESS BETWEEN B ECU AND C ECU |
Disconnect the C ECU connector and check for DTCs B1266 and B1267.
- OK:
- Neither DTC B1266 nor DTC B1267 is output.
- NOTICE:
- Reconnect the connector before starting the next check.
- HINT:
- If the result is as specified, the wire harness between the B ECU and C ECU is functioning normally but the disconnected C ECU is malfunctioning.
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| OK | ||
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| 6.CHECK WIRE HARNESS BETWEEN GATEWAY ECU AND A ECU OR C ECU |
Check for a short-circuit in B+ or body ground.
Disconnect the A ECU, C ECU and gateway ECU connectors.
Measure the resistance and voltage of the wire harness side connectors.
- Standard voltage:
Tester Connection Specified Condition A ECU connector/gateway ECU connector - Body ground Below 1 V C ECU connector/gateway ECU connector - Body ground Below 1 V
- Standard resistance:
Tester Connection Specified Condition A ECU connector/gateway ECU connector - Body ground 10 kΩ or higher C ECU connector/gateway ECU connector - Body ground 10 kΩ or higher
- HINT:
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| OK | ||
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