P0AA4

P310 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0AA4-232: Hybrid Battery Negative Conductor Circuit Stuck Closed

DTC P0AA4-232 - Hybrid Battery Negative Conductor Circuit Stuck Closed

DESCRIPTION

- The SMRs (System Main Relays), installed in the HV relay assembly, connect and disconnect the high-voltage power supply circuit in accordance with requests from the HV control ECU. To ensure a reliable operation, there are three SMRs in total (one for the negative side and two 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 operation of the SMRs (CON1, CON2, CON3) to check for malfunctions.






MONITOR DESCRIPTION

The HV control ECU monitors the system main relay No.3, 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 become stuck closed, it illuminates the MIL and sets a DTC.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





COMPONENT OPERATING RANGE





WIRING DIAGRAM





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 working on 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 is required to discharge the high-voltage capacitor inside the w/ converter inverter assembly.

PROCEDURE

1. CHECK HV RELAY ASSEMBLY
CAUTION: Be sure to wear insulated gloves.





(a) Turn the ignition switch off and remove the service plug grip. Hybrid Control System

NOTE: Do not put the vehicle into the READY-on state with the service plug grip removed as this may cause a malfunction.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





HINT:
- If a system main relay is stuck closed, inspect The HV relay assembly without removing it from the vehicle, in order to keep the relay closed.
- If P0AA4-232 is output, the HV relay assembly must be replaced. Measuring resistance can determine that this is either a present or past malfunction.

OK -- REPLACE HV RELAY ASSEMBLY
OK -- REPLACE HV RELAY ASSEMBLY