U029A

HYBRID BATTERY CONTROL: HYBRID BATTERY SYSTEM: U029A-123: Lost Communication with Hybrid Battery Pack Sensor Module

DTC U029A-123 - Lost Communication with Hybrid Battery Pack Sensor Module

DESCRIPTION

The battery smart unit detects the HV battery conditions (voltage, current, and temperature) and the battery cooling fan voltage, and sends the detected information to the hybrid vehicle control ECU.






WIRING DIAGRAM





INSPECTION PROCEDURE
CAUTION:
- Before inspecting the high-voltage system, 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.

PROCEDURE

1. CHECK WAVEFORM
CAUTION:
Be sure to wear insulated gloves.




(a) Connect an oscilloscope between the hybrid vehicle control ECU and battery smart unit terminals specified in the table below and measure the waveform.






OK:
The waveform appears as shown in the illustration.
NG -- CHECK AUXILIARY BATTERY
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
2. CHECK AUXILIARY BATTERY
(a) Turn the power switch off.
(b) Measure the voltage between the terminals of the auxiliary battery.
Standard voltage:






NG -- CHARGE OR REPLACE AUXILIARY BATTERY
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (IGCT VOLTAGE)
(a) Turn the power switch on (IG).




(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:





- For the removal and installation procedures related to the battery pack wire inspection, Components.
- Perform this inspection with the battery pack wire connected.

NG -- CHECK FUSE (IGCT3)
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (BATTERY SMART UNIT - BATTERY PACK WIRE CONNECTOR)
(a) Turn the power switch off.
(b) Disconnect the battery pack wire connector.
(c) Disconnect connector z36 from the battery smart unit.
HINT: For the removal and installation procedures related to the battery smart unit connector inspection, Components.




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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BATTERY SMART UNIT)
CAUTION:
Be sure to wear insulated gloves.
(a) Disconnect connector A76 from the hybrid vehicle control ECU.




(b) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):





(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. REPLACE BATTERY SMART UNIT
HINT: For the removal and installation procedures related to the battery smart unit, Components.

NEXT -- Continue to next step.
7. CLEAR DTC
(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) Clear DTCs and freeze frame data.
NEXT -- Continue to next step.
8. RECONFIRM DTC OUTPUT
(a) Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.
(b) Check if DTCs are output.
Result:






B -- COMPLETED
A -- REPLACE HYBRID VEHICLE CONTROL ECU
9. CHECK FUSE (IGCT3)




(a) Remove the IGCT3 fuse from the luggage room junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FUSE
OK -- Continue to next step.
10. CHECK FUSE (IGCT NO. 2)




(a) Remove the IGCT NO. 2 fuse from the engine room No. 3 relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FUSE
OK -- Continue to next step.
11. CHECK HARNESS AND CONNECTOR (BATTERY PACK WIRE CONNECTOR - IGCT2 RELAY)
CAUTION:
Be sure to wear insulated gloves.
(a) Disconnect the battery pack wire connector.
(b) Install the IGCT3 fuse to the luggage room junction block.
(c) Install the IGCT2 NO. 2 fuse to the engine room No. 3 relay block.
(d) Remove the IGCT2 relay from the engine room No. 2 relay block.
(e) Measure the resistance according to the value(s) in the table below.





Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK AND REPAIR POWER SOURCE CIRCUIT (IGCT2 RELAY POWER SOURCE)