P0AA1-233

P311 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0AA1-233: Hybrid Battery Positive Contactor Circuit Stuck Closed

DTC P0AA1-233 - Hybrid Battery Positive Contactor Circuit Stuck Closed

DESCRIPTION
The SMRs (System Main Relay) are the relays that connect or disconnect the high voltage power system in accordance with commands from the hybrid vehicle control ECU.
The SMR system is composed of three SMRs and one system main resistor. SMRB and SMRG are located on the HV relay assembly in the battery carrier under the HV battery. SMRP and the system main resistor are located in the hybrid vehicle converter (DC/DC converter) assembly in the battery carrier.
To connect to the high voltage power system, the vehicle will first turn on SMRP and SMRB to charge the vehicle through the system main resistor. Then, SMRP will be turned off after the SMRG is turned on. To shut off the high voltage power system, SMRB and SMRG are turned off.
When there is an open in the AMD line or IGCT line, the following DTCs are output:

This circuit uses the hybrid vehicle 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 or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. After removing the service plug grip, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
- After disconnecting the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.
HINT:
- Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.
- If P0AA1-233 is output, the vehicle is prevented from starting.

PROCEDURE

1. CHECK DTC OUTPUT (HV)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.
(d) Check if DTCs are output.
Result:

HINT:
- *1: If any INF codes are output for this DTC, refer to the corresponding diagnostic flowchart.
- Turning the power switch on (IG) with the service plug grip and inverter cover removed causes interlock switch system DTC P0A0D-350 to be output.
- P0AA1-233 may be output due to a malfunction which causes the DTCs in the table above to be output. In this case, first troubleshoot the output DTCs in the table above. Then, perform a reproduction test to check that no DTCs are output.

YES -- GO TO DTC CHART
NO -- Continue to next step.
2. CHECK HV RELAY ASSEMBLY (SMRB, SMRG)
CAUTION: Be sure to wear insulated gloves.
(a) Turn the power switch off and remove the service plug grip Hybrid Control System.
NOTICE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
(b) Disconnect the high voltage connector of the HV relay assembly Components.

- Leave the HV relay in the vehicle while testing to prevent the movement that occurs during removal from causing a stuck relay to return to normal.
- Measuring resistance can determine that this is either a present or past malfunction.

(d) Measure the resistance according to the value(s) in the table below. (SMRG inspection) (*2)
Standard resistance:

A -- REPLACE HV RELAY ASSEMBLY
B -- REPLACE HV RELAY ASSEMBLY