P0AA4

P112 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0AA4-232: Hybrid Battery Negative Contactor Circuit Stuck Closed

DTC P0AA4-232 - Hybrid Battery Negative 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.






MONITOR DESCRIPTION

The HV control ECU monitors the No. 3 system main relay, because shutting off the high-voltage system might be impossible if the relay terminal becomes stuck. If the HV control ECU detects that the relay terminal has stuck closed, it illuminates the MIL and sets a DTC.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





COMPONENT OPERATING RANGE





INSPECTION PROCEDURE

If the information (INF) code is present, replace the No. 3 system main relay.

PROCEDURE

1. REPLACE NO. 3 SYSTEM MAIN RELAY
(a) Replace the No. 3 system main relay Removal.
NEXT -- COMPLETED