DTC B120A (I-B4), B120A (8A)
DTC B120A, DTC screen I-B4, or DTC screen 8A : Climate Control Unit LIN Communication Bus Line Error
| DTC Description | DTC |
|---|---|
| B120A Climate Control Unit LIN Communication Bus Line Error |
DTC (AC)
- Problem verification
-1. Clear the DTCs with the HDS.
-2. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.
-3. Do the Self-Diagnostic Function with the HDS or the climate control unit .
-4. Check for DTCs.
DTC Description DTC B120A Climate Control Unit LIN Communication Bus Line Error Is DTC B120A, Error on the DTC screen I-B4 (climate control panel without display), or DTC screen 8A (climate control panel with display) indicated?
YES
The failure is duplicated. Go to step 2.
NO
Intermittent failure. Check for loose wires or poor connections on the climate control panel circuit.
- Fuse check
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Check the following fuse.
Fuse No. D9 Is the fuse OK?
YES
Go to step 3.
NO
Replace the fuse, and recheck. If the fuse blows again, repair a short in the No. D9 fuse circuit.
- Determine possible failure area (BUS-DATA line, IG2_A/C line)
-1. Disconnect the following connector.
Climate control panel 20P connector -2. Turn the vehicle to the ON mode.
-3. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode Climate control panel 20P connector: disconnected Test point 1 Climate control panel 20P connector (female terminals) No. 13: Test point 2 Climate control panel 20P connector (female terminals) No. 19: Is there battery voltage?
YES
Go to step 4.
NO
Go to step 7.
- Shorted wire check (BUS-DATA line)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connector.
Climate control unit connector A (32P) -3. Measure the resistance between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Climate control unit connector A (32P): disconnected Climate control panel 20P connector: disconnected Test point 1 Climate control unit connector A (32P) No. 29 Test point 2 Body ground Is there 1 MΩ or more?
YES
The BUS-DATA wire is not shorted. Go to step 5.
NO
Repair a short to ground in the BUS-DATA wire.
- Open wire check (BUS-DATA line)
-1. Measure the resistance between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Climate control unit connector A (32P): disconnected Climate control panel 20P connector: disconnected Test point 1 Climate control unit connector A (32P) No. 29 Test point 2 Climate control panel 20P connector (female terminals) No. 18: Is there 1.0 Ω or less?
YES
The BUS-DATA wire is OK. Go to step 6.
NO
Repair an open in the BUS-DATA wire.
- Climate control panel check
-1. Reconnect the following connector.
Climate control unit connector A (32P) -2. Substitute a known-good climate control panel .
-3. Clear the DTCs with the HDS.
-4. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.
-5. Do the Self-Diagnostic Function with the HDS or the climate control unit .
-6. Check for DTCs.
DTC Description DTC B120A Climate Control Unit LIN Communication Bus Line Error Is DTC B120A, Error on the DTC screen I-B4 (climate control panel without display), or DTC screen 8A (climate control panel with display) indicated?
YES
Replace the climate control unit .
NO
- Open wire check (IG2_A/C line)
-1. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode Climate control panel 20P connector: disconnected Test point 1 Climate control panel 20P connector (female terminals) No. 19: Test point 2 Body ground Is there battery voltage?
YES
Check for an open in the GND wire between the climate control panel and body ground. If the wire is OK, check for poor ground at G402.
NO
Repair an open in the IG2_A/C wire.