DTC No. P0A8D-00 RMCU control power supply voltage-low

DTC SET CONDITION

Check Condition

All the time during operation

Judgment Criterion

The low IGCT power supply voltage is detected.

TROUBLESHOOTING HINTS

Malfunction of the 12V battery (deteriorated/poor charging/loose terminals/contamination of terminals)
Malfunction of the REMCU power supply circuit system (blown fuse)
Malfunction of the IGCT control relay
Malfunction of the PHEV-ECU
Malfunction of the on board charger (OBC)/DC-DC converter
Malfunction of the rear motor (malfunction of the REMCU)

note	The DTC may be set due to the 12V battery runout by leaving the vehicle with the power supply mode of the electric motor switch in ON condition.

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.M.U.T.-IIISE other system DTC

Check whether the PHEV-ECU sets the following DTC.

DTC No. P0A8D-00 Low voltage of auxiliary battery fault
DTC No. P1A2F-92 DC/DC Converter fault
DTC No. P1A56-12 IGCT relay Control Circuit High
DTC No. U1E08-87 Lost Communication with DC/DC Converter

Is the DTC set?

Troubleshoot the set DTCs (Refer to DIAGNOSTIC TROUBLE CODE CHART

2.IGCT control relay check

Check the IGCT control relay (Refer to IGCT CONTROL RELAY CONTINUITY CHECK

Is the check result normal?

Replace the IGCT control relay.

3.Voltage measurement of the IGCT control relay power supply

(1) Remove the IGCT control relay, and measure at the fuse block side.

(2) Measure the voltage between the IGCT control relay connector (contact side upstream terminal) and body ground.

OK: Battery voltage

Is the check result normal?

Repair or replace the faulty part.

4.Check of short to ground circuit and open circuit in IGCT line between rear motor assembly (REMCU) and IGCT control relay

caution

Check that there is no foreign material inside the connector, and check the inappropriate connection of the connector and break of the pin.

Is the check result normal?

Repair the connector(s) or wiring harness.

5.Check of continuity in ground line between rear motor assembly (REMCU) and body ground

caution

Check that there is no foreign material inside the connector, and check the inappropriate connection of the connector and break of the pin.

(1) Disconnect the rear motor assembly connector (REMCU), and measure at the wiring harness side.

(2) Check the continuity between the rear motor assembly connector (REMCU) (ground terminal) and body ground.

OK: Continuity exists (2 Ω or less)

Is the check result normal?

Repair the connector(s) or wiring harness in gorund line between the rear motor assembly (REMCU) connector and body ground.

6.Check whether the DTC is set again.

(1) Erase the set DTC.

(2) Change the power supply mode of the electric motor switch to OFF, then wait for 2 minutes or more in key lock condition. (Check that the P indicator on the selector lever turns off.)

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

(4) Check whether the DTC is set again.

Is the DTC set?

Replace the rear motor assembly (Refer to MOTOR (ELECTRIC MOTOR UNIT) REMOVAL AND INSTALLATION

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