P0AA1-233

P310 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0AA1-233: Hybrid Battery Positive Conductor Circuit Stuck Closed

DTC P0AA1-233 - Hybrid Battery Positive 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.

- This circuit uses the HV control ECU to monitor the system main relays and stops the system if a malfunction is detected in the relays, because it may be impossible to shut off the high-voltage system if any of the relays becomes stuck.

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.
- If P0AA1-233 is output, the vehicle is prevented from starting.

PROCEDURE

1. READ OUTPUT DTC (HV)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.
(d) Read output DTCs. Hybrid Control System

YES -- GO TO DTC CHART
NO -- Continue to next step.
2. 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

CAUTION: Do not reinsert the service plug grip until replacement of the HV relay assembly is completed.
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. (Inspection of SMR1 and SMR2)
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 P0AA1-233 is output, the HV relay assembly must be replaced. Measuring resistance can determine that this is either a present or past malfunction.
- If the resistance is between 28.5 and 31.5 Ohms, it can be determined that the system main relay No.1 is stuck closed.

- 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 P0AA1-233 is output, the HV relay assembly must be replaced. Measuring resistance can determine that this is either a present or past malfunction.

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