Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Hybrid/EV Battery Internal Electronic Failure (P31B549)

Toyota Corolla Cross (2022-2025) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Hybrid Battery System / Hybrid/EV Battery Internal Electronic Failure (P31B549)

DESCRIPTION

The battery ECU assembly monitors its internal operation and will store these DTCs when it detects an internal malfunction.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

Note

P31B549

Hybrid/EV Battery Internal Electronic Failure

An abnormal signal is detected by the battery ECU assembly (excessive discharging current).

(1 trip detection logic)

Hybrid vehicle control ECU

Does not come on

Master Warning:

Comes on

SAE Code: P31B5

CONFIRMATION DRIVING PATTERN

HINT:

After repairs have been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

Click here

  1. Connect the GTS to the DLC3.
  2. Turn the ignition switch to ON and turn the GTS on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  4. Turn the ignition switch off and wait for 2 minutes or more.
  5. Turn the ignition switch to ON and turn the GTS on.
  6. Drive the vehicle on urban roads for approximately 10 minutes.
  7. Enter the following menus: Powertrain / HV battery / Utility / All Readiness.
  8. Check the DTC judgment result.

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE, perform driving pattern again.

PROCEDURE

1.

CHECK DTC OUTPUT (HV BATTERY, HYBRID CONTROL)

(a) Check for DTCs.

Powertrain > HV Battery > Trouble Codes Powertrain > Hybrid Control > Trouble Codes

Result

Proceed to

"P31B549" only is output.

A

DTCs except "P31B549" of hybrid battery system are output.

B

DTCs except "P31B549" of hybrid control system are output.

C

(b) Turn the ignition switch off.

A

REPLACE HYBRID VEHICLE CONTROL ECU

B

GO TO DTC CHART (HYBRID BATTERY SYSTEM)
C

GO TO DTC CHART (HYBRID CONTROL SYSTEM)

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