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

1. Remove the service plug grip. Refer to REMOVAL .
2. Remove the battery smart unit. Refer to REMOVAL .
3. Disconnect connector n2 from the battery smart unit.
4. Turn the power switch on (IG).
5. Measure the voltage according to the value(s) in the table below.
   Fig 1: Identifying Battery Smart Unit N2 Connector Terminal Identification

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard voltage

   Tester Connection	Specified Condition
   IGC1 (n2-1) - GND (n2-5)	11 to 14 V

   HINT: 

   If the power switch is turned on (IG) with the service plug grip removed, DTC P0A0D-350 for the interlock switch system will be set.

NG → See step   6 

OK: Go to next step 

1. Disconnect connector A61 from the hybrid vehicle control ECU.
2. Measure the resistance according to the value(s) in the table below.
   Fig 2: Identifying A61 And N2 Connectors Terminal Identification

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance (Check for open)

   Tester Connection	Specified Condition
   BTH+ (A61-104) - BTH+ (n2-2)	Below 1 Ω
   BTH- (A61-103) - BTH- (n2-3)	Below 1 Ω

   Standard resistance (Check for short)

   Tester Connection	Specified Condition
   BTH+ (A61-104) or BTH+ (n2-2) - Body ground	10 kΩ or higher
   BTH- (A61-103) or BTH- (n2-3) - Body ground	10 kΩ or higher

3. Turn the power switch on (IG).
4. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Specified Condition
   BTH+ (A61-104) - Body ground	Below 1 V
   BTH- (A61-103) - Body ground	Below 1 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Connect connector A61 to the hybrid vehicle control ECU.
2. Connect connector n2 to the battery smart unit.
3. Connect an oscilloscope between the battery smart unit terminals specified in the table below, and measure the waveform.
   Fig 3: Identifying Battery Smart Unit N2 Connector Terminal Identification With Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Item	Contents
   Terminal	CH1: BTH+ (n2-2) - GND (n2-5) CH2: BTH- (n2-3) - GND (n2-5)
   Equipment Setting	2 V/DIV., 500 μs/DIV.
   Condition	Power switch on (IG)

NG → See step   4 

OK → See step   5 

1. Remove the IGCT relay from the engine room R/B.
2. Disconnect connector n2 from the battery smart unit.
3. Measure the resistance according to the value(s) in the table below.
   Fig 4: Identifying Connector Terminal Identification

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance (Check for open)

   Tester Connection	Specified Condition
   IGC1 (n2-1) - IGCT relay 5	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → CHECK AND REPAIR POWER SOURCE CIRCUIT