DTC C1C51 HPCM Regenerative Brake Control System

DTC detecting condition: 

Internal abnormality signal is input as abnormal when communication from hybrid vehicle control ECM has been established.

Trouble symptom: 

• Regenerative brake cannot be controlled.
• Brake assist does not operate.
• EyeSight functions (ACC/PCS) do not operate.

1. CHECK DTC OF HYBRID VEHICLE CONTROL ECM  .

   Read the DTC of [P-HEV Hybrid Powertrain Control] using the Subaru Select Monitor. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Are any DTCs displayed?

   Yes:  Perform the diagnosis according to the DTC. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  2.

2. CHECK DTC OF INVERTER WITH CONVERTER ASSEMBLY  .

   Read the DTC of [P-HEV Drive Motor] using the Subaru Select Monitor. Ref. to P-HEV DRIVE MOTOR (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Are any DTCs displayed?

   Yes:  Perform the diagnosis according to the DTC. Ref. to P-HEV DRIVE MOTOR (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  3.

3. CHECK DTC OF ECM  .

   Read the DTC of [Engine Control System] using the Subaru Select Monitor. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>DIAGNOSTIC TROUBLE CODE (DTC) .

   Are any DTCs displayed?

   Yes:  Perform the diagnosis according to the DTC. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  4.

4. CHECK DTC OF BATTERY ECM ASSEMBLY  .

   Read the DTC of [P-HEV High Voltage Battery] using the Subaru Select Monitor. Ref. to P-HEV HIGH VOLTAGE BATTERY (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Are any DTCs displayed?

   Yes:  Perform the diagnosis according to the DTC. Ref. to P-HEV HIGH VOLTAGE BATTERY (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  5.

5. DIAGNOSTICS WITH PHENOMENON OF HYBRID VEHICLE CONTROL ECM  .

   Check the list of (DIAGNOSTICS with Phenomenon of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>LIST .

   Is the malfunction in the list occurring?

   Yes:  Replace the Hybrid vehicle control ECM. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

   No:  Go to  6.

6. CHECK DTC OF EBB CONTROL MODULE  .
   1. Using the Subaru Select Monitor, perform the clear memory of [Electric Brake Booster]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
   2. Read the DTC of [Electric Brake Booster] using the Subaru Select Monitor. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is a DTC other than DTC C1C51 displayed?

   Yes:  Perform the diagnosis according to the DTC. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  7.

7. CHECK DTC OF EBB CONTROL MODULE  .

   Read the DTC of [Electric Brake Booster] using the Subaru Select Monitor. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC C1C51 displayed?

   Yes:  Replace the brake booster assembly (with the master cylinder). Ref. to BRAKE>BRAKE BOOSTER .

   No:  Currently, it is normal. There may have been a temporary poor contact in the harness and connector or a temporary noise interference.