P0AA4

L110 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 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 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:






P0AE6-225 is output first because the time required for diagnosis is the shortest.






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, check the voltage at 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 DTC P0AA4-232 is stored, the vehicle will not turn on.

PROCEDURE

1. CHECK DTC OUTPUT
(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:






YES -- GO TO DTC CHART
NO -- Continue to next step.
2. CHECK FREEZE FRAME DATA
(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) Read output DTCs.
(e) Read the freeze frame data of P0AA4-232.
Result:






A -- REPLACE INVERTER WITH CONVERTER ASSEMBLY
B -- Continue to next step.
3. CHECK HV RELAY ASSEMBLY
CAUTION:
Be sure to wear insulated gloves.




(a) Turn the power switch off and remove the service plug grip L110 Hybrid Vehicle 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) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT:
- For the removal and installation procedures related to inspection 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.
- If the result of reading the freeze frame data is B, 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