REGENERATIVE BRAKING IS NOT POSSIBLE


id300300000400


Outline

Malfunction symptom

Regenerative braking is not possible

Description
•  During deceleration, the high voltage battery level indication does not increase.
•  During deceleration, the power meter does not move to the CHARGE side (However, except for immediately after charging is completed or when high voltage battery is at low temperature).
•  The amount of increase in the high voltage battery level indication varies even if the vehicle speed is decreased by the same power.
•  Variation in deceleration when releasing the accelerator pedal.
Possible cause
Regenerative braking amount is restricted:
•  PCM restricts regenerative braking amount based on signal from drive motor control module
―  Fail-safe due to drive motor control module-related DTC detection
―  Excessive temperature increase in electric motor or inverter
•  PCM restricts regenerative braking amount based on signal from BECM
―  Fail-safe due to BECM-related DTC detection
―  High voltage battery structural part malfunction
―  High voltage battery temperature is high or low
―  High voltage battery is fully charged and power generated by regenerative braking cannot be accepted (normal operation)
•  The PCM restricts the regenerative braking amount based on the signal from the electronically controlled brake unit. (normal operation)
―  Driving on slippery road
―  Vehicle condition where wheel slip is likely to occur, such as during sudden steering wheel maneuvering
Regenerative braking inhibition condition:
•  PCM restricts regenerative braking based on signal from electronically controlled brake unit
―  During DSC operation (normal operation)
―  During ABS operation (normal operation)
―  Electronically controlled brake system malfunction
Target regenerative braking amount changes:
•  PCM detects drive mode change
―  Deceleration and acceleration rate switching detected due to operation of steering shift switch (normal operation)
―  Selector lever shifted to N position (normal operation)
System wiring diagram
•  Not applicable
Connector diagram
•  Not applicable


Diagnostic Procedure

Step

Inspection

Results

Action

1
VERIFY EV SYSTEM RELATED DTCs
•  Perform the DTC inspections for the following modules.
―  PCM
―  BECM
―  Drive motor control module
―  Electronically controlled brake unit
•  Are DTCs displayed?
Yes
Repair the malfunctioning location according to the applicable DTC troubleshooting.
No
Go to the next step.
2
VERIFY HOW CUSTOMER USES VEHICLE
•  Verify the following driving conditions based on the contents of the interview with the customer.
―  Steering shift switch operation
―  Selector lever shifted to N position
―  ABS operation
―  DSC operation
―  Driving on slippery road
―  Vehicle condition where wheel slip is likely to occur, such as during sudden steering wheel maneuvering
•  Does the customer’s driving situation apply?
Yes
Explain to the customer that the regenerative braking inhibition or restriction is performed due to the driving operations when the customer decelerates.
No
Explain to the customer that the regenerative braking inhibition or restriction is performed when the vehicle detects the following during deceleration.
•  High voltage battery is fully charged and power generated by regenerative braking cannot be accepted (high voltage battery state of charge (SOC) is 95% or more)
•  Excessive temperature increase in electric motor or inverter
•  High voltage battery temperature is high or low
Repair completion verification
VERIFY THAT VEHICLE IS REPAIRED
•  Install/connect the part removed/disconnected during the troubleshooting procedure.
•  Has the malfunction symptom been eliminated?
Yes
Complete the symptom troubleshooting. (Explain contents of repair to customer.)
No
Refer to the CAN (controller area network) malfunction diagnosis flow to inspect for a CAN communication error.