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Home >> Suzuki >> 2006 >> Grand Vitara Premium, RWD, Standard >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Air Conditioning System >> Diagnostic Information And Procedures >> DTC B1551: Serial Communication Circuit Malfunction >> DTC Troubleshooting
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DTC Troubleshooting

DTC TROUBLESHOOTING CHART

Step Action YES NO
DTC check 
  1. Connect scan tool to DLC with ignition switch turned OFF.
  2. Turn ignition switch ON and clear DTC referring to DTC CLEARANCE .
  3. Disconnect connector from information display with ignition switch turned OFF.
  4. Turn ignition switch ON and check DTC referring to DTC CHECK .

Is there DTC B1551? 
Go to Step 2. Information display faulty.
Wire harness check 
  1. Disconnect connectors from BCM and HVAC control module.
  2. Measure resistance between "G30-5" terminal of BCM connector and "G52-10" terminal of HVAC control module connector.

Is resistance below 5 Ω? 
Go to Step 3. "YEL/RED" wire open or high resistance circuit.
Wire harness check 
  1. Measure resistance between "G52-10" terminal of HVAC control module connector and vehicle body ground.

Is resistance infinity? 
Go to Step 4. "YEL/RED" wire shorted to ground circuit.
Wire harness check 
  1. Measure voltage between "G52-10" terminal of HVAC control module connector and vehicle body ground with ignition switch turned ON.

Is voltage 0 V? 
Go to Step 5. "YEL/RED" wire shorted to other circuit.
Serial communication signal check 
  1. Connect connectors to BCM and HVAC control module.
  2. Using oscilloscope, check that serial communication signal at "G30-5" is outputted referring to "VOLTAGE CHECK " in INSPECTION OF BCM AND ITS CIRCUITS .

Is serial communication signal outputted at "G30-5" terminal of BCM connector? 
HVAC control module faulty. BCM (included in junction block assembly) faulty.