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DTC P1B7C: Charge-Discharge connector 12V relay circuit low
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
TROUBLE JUDGMENT
The V2H relay excitation circuit is open or shorted to ground.
 
 
PROBABLE CAUSES
  • Malfunction of CAN bus line.
  • Damaged harness or connector.
  • The power supply circuit to the V2H is defective.
  • Malfunction of the V2H relay.
  • Malfunction of the PHEV-ECU.
 
 
DIAGNOSIS
Required Special Tools
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose CAN bus line.
Diagnose the CAN bus lines.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.
 
STEP 2. Check the V2H relay.
Refer to .
Is the check result normal?
Go to Step 3.
Replace the V2H relay.
 
STEP 3. Check the power supply line for short to ground (The V2H relay connector and the quick charging connector).
Check the wiring harness between the V2H relay connector (terminal No.3) and the quick charging connector (terminal No.5).
Is the check result normal?
Go to Step 4.
Repair the connector or wiring harness.
 
STEP 4. Voltage measurement at the V2H relay connector.
(1) Remove the V2H relay, and measure at the relay box side.
(2) Turn on the power supply mode of the electric motor switch.
(3) Measure the voltage between terminal No.1 and body ground.
OK: System voltage
Is the check result normal?
Go to Step 5.
Repair the connector or wiring harness.
 
STEP 5. Check the V2HR line for open and short to ground (The V2H relay connector and the PHEV-ECU connector).
Check the wiring harness between the V2H relay connector and the PHEV-ECU connector (terminal V2HR).
Is the check result normal?
Go to Step 6.
Repair the connector or wiring harness.
 
STEP 6. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
(1) Erase the DTC.
(2) Turn on the power supply mode of the electric motor switch.
(3) Check if the DTC is set.
Is the DTC set?
Replace the PHEV-ECU (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).