DTC B1550-H / B1550-L
Precautions: Precautions for Diagnosing Trouble · General safety (00)
DTC Detecting Condition and Trouble Area
| DTC detecting condition | Trouble area |
|---|---|
|
B1550-H: Lost Communication between HVAC Control Module and Auto A/C Panel Between HVAC control module and auto A/C panel, communication signal voltage is higher than specified value for specified time continuously. |
•Communication circuit
•HVAC control module •Auto A/C panel |
|
B1550-L: Lost Communication between HVAC Control Module and Auto A/C Panel Between HVAC control module and auto A/C panel, communication signal voltage is lower than specified value for specified time continuously. |
Circuit Diagram
| [A]: | HVAC control module connector (View: [a]) | A1. | LIN communication signal circuit | 2. | HVAC control module |
| [B]: | Auto A/C panel connector (View: [a]) | 1. | Auto A/C panel | 3. | LIN driver |
DTC Confirmation Procedure
1)Start engine and operate A/C system.
DTC Troubleshooting
| Step | Action | Yes | No |
|---|---|---|---|
| 1 |
DTC check
1)Set ignition “ON”.
2)Set ignition “OFF”.
3)Set ignition “ON” and check for DTC.
Is DTC B1550-H or B1550-L still detected?
|
Go to Step 2.
|
Intermittent trouble.
|
| 2 |
LIN communication signal circuit check
1)Disconnect “G20” and “G227” connectors.
2)Check the following points.
•Resistance of “A1” circuit: less than 1 Ω
•Resistance of “A1” circuit between auto A/C panel and ground: infinity Are resistances as specified?
|
Replace HVAC control module and/or auto A/C panel and recheck DTC.
•HVAC control module:
 •Auto A/C panel: |
Replace instrument panel harness.
|