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 voltages, and sends the detected information to the hybrid vehicle control ECU via serial communication.






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.
HINT: Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (VOLTAGE)
CAUTION: Be sure to wear insulated gloves.
(a) Remove the service plug grip. Removal

(b) Remove the luggage compartment trim cover front. Removal

(c) Disconnect the frame wire. Removal

(d) Remove the battery bracket sub-assembly. Removal

(e) Connect the auxiliary battery positive terminal cable of the frame wire.
(f) Turn the power switch on (IG).





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






NG -- CHECK FUSE (IGCT NO. 3 FUSE)
OK -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BATTERY SMART UNIT)
CAUTION: Be sure to wear insulated gloves.
(a) Disconnect connector A54 from the hybrid vehicle control ECU.
(b) Disconnect connector N2 from the battery smart unit.





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






Standard resistance (Check for short):





(d) Turn the power switch on (IG).
(e) 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.
3. CHECK WAVEFORM
CAUTION: Be sure to wear insulated gloves.
(a) Connect connector A54 from the hybrid vehicle control ECU.
(b) Connect connector N2 to the battery smart unit.





(c) Connect an oscilloscope between the battery smart unit terminals specified in the table below, and measure the waveform.






NG -- REPLACE BATTERY SMART UNIT
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
4. CHECK FUSE (IGCT NO. 3 FUSE)





(a) Remove the IGCT NO. 3 fuse from the engine room R/B No. 1.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:
Below 1 Ohms
NG -- READ VALUE USING FUSE (IGCT NO. 3 FUSE)
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR
CAUTION: Be sure to wear insulated gloves.
(a) Install the IGCT NO. 3 fuse to the engine room R/B No. 1.
(b) Remove the integration relay from the engine room R/B No. 1.
(c) Disconnect connector N2 from the battery smart unit.





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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK AND REPAIR POWER SOURCE CIRCUIT