DTC No. P1B01-1C 12V Battery Voltage Saturation Diagnosis

DTC SET CONDITION

Check Condition

During the BMU operation

Judgment Criterion

The abnormal voltage of the 12V battery is detected.

TROUBLESHOOTING HINTS

Malfunction of the On Board Charger (OBC)/DC-DC converter
Damaged wiring harness and connectors
Malfunction of the BMU

note	The DTC No. P1B01-1C may be set when the 24V battery is accidentally connected.

DIAGNOSIS

Required Special Tools:

MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
MB992745: V.C.I.-Lite main harness A
MB992747: V.C.I.-Lite USB cable short
MB992748: V.C.I.-Lite USB cable long
MB991223: Wiring harness set
MB992006: Extra fine probe

1.Check of other system DTC

Check whether the DC-DC converter sets the following DTC.

DTC No. P1AA2-A3 DCDC output voltage failure

Is the DTC set?

Troubleshoot the set DTC (Refer to DIAGNOSTIC TROUBLE CODE CHART

2.Voltage measurement at drive battery connector (control wiring harness connector) (BMU power supply line)

(1) Disconnect the connector, and measure at the wiring harness side.

(2) Measure the voltage of the following.

Voltage between the drive battery connector (control wiring harness connector) (terminal No. 5) and body ground

OK: Battery voltage

Is the check result normal?

Repair the faulty part.

3.Check whether the DTC is set again.

(1) Erase the DTC set in the BMU2.

(2) Erase the DTC set in the BMU.

(3) Change the power supply mode of the electric motor switch to ON (READY indicator: ON).

(4) Wait for 1 minute or more.

(5) Check whether the DTC is set again.

Is the DTC set?

The trouble can be an intermittent malfunction (Refer to General Information - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS

4.Drive battery control wiring harness check (BMU power supply line)

(1) Disassemble the drive battery (Refer to SERVICE PROCEDURE

(2) Check the following wiring harness for open circuit.

Between the BMU connector (BAT terminal) and the drive battery connector (control wiring harness connector) (terminal No. 5)

Is the check result normal?

Replace the BMU (Refer to BATTERY MANAGEMENT UNIT (BMU) REMOVAL AND INSTALLATION

Repair the connector(s) or wiring harness.