P0AA1-231

P112 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0AA1-231: Hybrid Battery Positive Contactor Circuit Stuck Closed

DTC P0AA1-231 - Hybrid Battery Positive Contactor Circuit Stuck Closed

DESCRIPTION





The SMRs (System Main Relays) connect and disconnect the high-voltage power supply circuit in accordance with requests from the HV control ECU. To ensure a reliable operation, they consists of a total of 3 relays (1 for the negative side and 2 for the positive side).
To connect, SMR1 and SMR3 turn ON initially. Then, SMR2 turns ON and SMR1 turns OFF. This process protects the circuit from the high-voltage surge current by allowing the limit current to flow via the resistor. To disconnect, SMR2 and SMR3 turn OFF in that order. The HV control ECU checks that the relays have turned OFF properly.
The HV control ECU monitors the proper operation of the SMRs (CON1, CON2 and CON3) to check for a malfunction.

Because it might be impossible to shut off the high-voltage system if either of the No. 1 and No. 2 system main relays becomes stuck, the HV control ECU monitors the two relays and stops the system if malfunction is found in either relay.






INSPECTION PROCEDURE
CAUTION:
- Before inspecting the high-voltage system, take safety precautions to prevent electrical shocks, such as wearing insulated gloves and removing the service plug grip. After removing the service plug grip, put it in your pocket to prevent other technicians from reconnecting it while you are servicing the high-voltage system.
- After disconnecting the service plug grip, wait for at least 5 minutes before touching any of the high-voltage connectors or terminals.
HINT: At least 5 minutes are required to discharge the high-voltage condenser inside the inverter.

PROCEDURE

1. INSPECT NO. 1 SYSTEM MAIN RELAY
(a) Inspect the No. 1 system main relay System Main Relay.
NG -- REPLACE NO. 1 SYSTEM MAIN RELAY
OK -- REPLACE NO. 2 SYSTEM MAIN RELAY