STOP AND START SYSTEM(for 2WW) Backup Boost Converter Circuit
| DTC Code | DTC Name |
|---|---|
| Backup Boost Converter Circuit |
DESCRIPTION
A backup boost converter is built into the engine stop and start ECU. The backup boost converter helps maintain the power source voltage when the engine is restarted by stop and start control.
This prevents various functions such as the audio and visual system or navigation system from failing if the power source voltage drops due to the battery voltage dropping when the engine is restarted by stop and start control. If a DTC is output, troubleshoot the DTC first.
A relay function and fuse function are provided in the backup boost converter.
If there is a malfunction in any of the electrical system circuits connected to the backup boost converter, the fuse and relay functions shut off the malfunctioning circuit to protect other circuits (remains shut off until next trip).
When the electrical system circuit is shut off, power to the circuit is cut off, causing any systems connected to the circuit to be disabled.
The fuse function is reset* when the ignition switch is turned off. If the malfunction still exists in the electrical system circuit that has been shut off by the relay function, it will be shut off again by the relay and fuse functions the next time the ignition switch is turned to ON.
*: A semiconductor fuse self-resets according to electric signals.
The backup boost converter supplies power to:
Main body ECU (multiplex network body ECU)
Skid control ECU (Brake actuator assembly)
Spiral with sensor cable sub-assembly
Power steering ECU assembly
Combination meter assembly
Radio receiver assembly, radio and display receiver assembly or navigation receiver assembly
Inner rear view mirror assembly
Lane departure warning camera
Tire pressure warning ECU and receiver
Blind spot monitor sensor LH
Blind spot monitor sensor RH
Parking assist ECU
Driving support ECU assembly
Millimeter wave radar sensor assembly
Network Gateway ECU
WIRING DIAGRAM
CAUTION / NOTICE / HINT
Before replacing the engine stop and start ECU, read the number of starter operations and write it into a new engine stop and start ECU.
After replacing the engine stop and start ECU or air conditioning amplifier assembly, reset and perform learning of the air conditioning information in the engine stop and start ECU.
After replacing the engine stop and start ECU or airbag sensor assembly, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.
Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
CHECK PROBLEM SYMPTOMS
Determine the trouble area by referring to the table below.
Effect on Vehicle
Trouble Area/Cause
Fail-safe
DTC Output
Stop and start cancel indicator light
Symptom
Proceed to
When the engine is restarted by stop and start control, the following symptoms may occur.
The audio and visual system or navigation system is reset
The combination meter assembly fades out
The steering wheel feels heavy when the engine is restarted*
*: A DTC may be stored in the power steering system
Backup boost converter internal malfunction
Internal power source malfunction
Internal power source overvoltage
Duty error
Communication cycle error
Stop and start control prohibited
P323B
Blinks
Converter output voltage cannot be boosted when the engine is restarted
A
Battery voltage drop
Systems on the converter output side do not operate
B41 terminal:
Parking assist ECU
B42 terminal: All of the following will not operate
Radio receiver assembly
Navigation receiver assembly
Radio and display receiver assembly
IG41 terminal: All of the following will not operate
Inner rear view mirror assembly
Lane departure warning camera
Tire pressure warning ECU and receiver
Blind spot monitor sensor LH
Blind spot monitor sensor RH
Network gateway ECU
Millimeter wave radar sensor assembly
Driving support ECU assembly
Parking assist ECU
Systems whose power is supplied from the main body ECU (multiplex network body ECU)
Overcurrent applied to an output terminal (output terminal relay circuit is shutoff)
Stop and start control is prohibited
(Connected ECUs or sensors may detect power source malfunction DTCs)
B22C0
Blinks
Systems do not operate as power supply from the converter is cut off
A
Systems do not operate
(Due to converter input side malfunction)
IG1 terminal: All of the following do not operate
Brake actuator assembly
Spiral with sensor cable sub-assembly
Power steering ECU assembly
Inner rear view mirror assembly
Lane departure warning camera
Tire pressure warning ECU and receiver
Blind spot monitor sensor LH
Blind spot monitor sensor RH
Network gateway ECU
Millimeter wave radar sensor assembly
Driving support ECU assembly
Systems whose power is supplied from the main body ECU (multiplex network body ECU)
IG2 terminal:
The combination meter assembly will not function
ACC terminal: All of the following will not operate
Radio receiver assembly
Navigation receiver assembly
Radio and display receiver assembly
Parking assist ECU
Converter input circuit malfunction
Open or short to GND in IG1 circuit
Open or short to GND in IG2 circuit
Open or short to GND in ACC circuit
Stop and start control prohibited
-
Does not blink (Blinks when communication error DTCs are stored)
Systems do not operate as power supply from the converter is cut off
B
Systems on the converter output side do not operate
(varies depending on the malfunctioning relay circuit the converter detected)
AC41 terminal:
The radio receiver assembly will not function
The navigation receiver assembly will not function
The radio and display receiver assembly will not function
The parking assist ECU will not function
IG11 terminal:
The power steering ECU assembly will not function
IG12 terminal:
The combination meter assembly will not function
IG31 terminal:
The brake actuator assembly will not function
The spiral with sensor cable sub-assembly will not function
Malfunction in circuits the converter supplies power to
(between the converter and ECUs or sensors)
Open or short in the combination meter assembly circuit
Related systems do not operate as the relay circuit in the converter is turned off
-
Does not blink (Blinks when communication error DTCs are stored)
Systems do not operate as power supply from the converter is cut off
B
All of the following will operate
Inner rear view mirror assembly
Lane departure warning camera
Tire pressure warning ECU and receiver
Blind spot monitor sensor LH
Blind spot monitor sensor RH
Network gateway ECU
Millimeter wave radar sensor assembly
Driving support ECU assembly
Parking assist ECU
Systems whose power is supplied from the main body ECU (multiplex network body ECU)
Open in BBC fuse circuit
Short in converter circuit
Backup boost converter malfunction
Radio receiver assembly
Navigation receiverassembly
Radio and display receiver assembly
Stop and start control prohibited
P0617
Does not blink (Due to disabled meter/gauge system)
All systems that the converter supplies power to do not operate (see circuit diagram)
A
P323B
The audio and visual system or navigation system does not function
(until the ignition switch is turned off)
Excessive audio volume
Data List item "State of BBC" displays "BBC Overcurrent" while the circuit is protected
The relay circuit in the converter is turned off to cut off power supply to the audio and visual system or navigation system (Returns to normal when the ignition switch is turned off)
-
Does not blink
If overcurrent is detected in the audio and visual system or navigation system, system operation is disabled while the ignition switch is ON
(Returns to normal when the ignition switch is turned off)
C
The radio receiver assembly, navigation receiver assembly, radio and display receiver assembly or parking assist ECU cannot be turned off (short between AC41 and +B)
The combination meter assembly cannot be turned off (short between IG12 and +B)
Communication error DTCs may be stored due to short between IG31 and +B
Tip:Varies depending on the number of times an open occurs in the +B circuit
Converter circuit malfunction
Short between AC41 and +B
Short between IG12 and +B
Short between IG31 and +B
-
-
Does not blink
The converter cannot shut off power source when the ignition switch is turned off
B
Ignition switch does not turn to ACC (short between ACC and +B)
Ignition switch does not turn off (short between IG1 or IG2 and +B)
Engine stop and start ECU power source circuit malfunction
Short between ACC and +B
Short between IG1 and +B
Short between IG2 and +B
-
-
Does not blink
Ignition switch does not turn to ACC
Ignition switch does not turn off
B
Result
Proceed to
A
B
C
C CHECK AUDIO AND VISUAL SYSTEM OR NAVIGATION SYSTEMClick here
CHECK ENGINE STOP AND START ECU (POWER SOURCE CIRCUIT)
-
*a
Front view of wire harness connector
(to Engine Stop and Start ECU)
Disconnect the engine stop and start ECU connector.
Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection
Condition
Specified Condition
A86-1 (BIN2) - Body ground
Always
9.5 to 14 V
A86-3 (BIN1) - Body ground
Always
9.5 to 14 V
Turn the ignition switch ACC.
Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection
Condition
Specified Condition
G87-19 (ACC) - Body ground
Ignition switch ACC
9.5 to 14 V
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection
Condition
Specified Condition
G87-18 (IG2) - Body ground
Ignition switch ON
9.5 to 14 V
G87-21 (IG1) - Body ground
Ignition switch ON
9.5 to 14 V
Turn the ignition switch off.
Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection
Condition
Specified Condition
G87-18 (IG2) - Body ground
Ignition switch off
0 to 1 V
G87-19 (ACC) - Body ground
Ignition switch off
0 to 1 V
G87-21 (IG1) - Body ground
Ignition switch off
0 to 1 V
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE HARNESS OR CONNECTOR
-
CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - EACH ECU OR SENSOR)
Disconnect the connector from the corresponding system ECU/sensor.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Table 1. Radio Receiver Assembly (for Radio Receiver Type) Tester Connection
Condition
Specified Condition
G87-12 (B42) - G46-4 (+B1)
Always
Below 1 Ω
G87-24 (AC41) - G46-3 (ACC1)
Always
Below 1 Ω
G87-12 (B42) - Body ground
Always
10 kΩ or higher
G87-24 (AC41) - Body ground
Always
10 kΩ or higher
G46-4 (+B1) - Body ground
Always
10 kΩ or higher
G46-3 (ACC1) - Body ground
Always
10 kΩ or higher
Table 2. Navigation Receiver Assembly (for Navigation Receiver Type) Tester Connection
Condition
Specified Condition
G87-12 (B42) - G137-4 (+B1)
Always
Below 1 Ω
G87-24 (AC41) - G137-3 (ACC1)
Always
Below 1 Ω
G87-12 (B42) - Body ground
Always
10 kΩ or higher
G87-24 (AC41) - Body ground
Always
10 kΩ or higher
G137-4 (+B1) - Body ground
Always
10 kΩ or higher
G137-3 (ACC1) - Body ground
Always
10 kΩ or higher
Table 3. Radio and Display Receiver Assembly (for Radio and Display Receiver Type) Tester Connection
Condition
Specified Condition
G87-12 (B42) - G141-4 (+B1)
Always
Below 1 Ω
G87-24 (AC41) - G141-3 (ACC1)
Always
Below 1 Ω
G87-12 (B42) - Body ground
Always
10 kΩ or higher
G87-24 (AC41) - Body ground
Always
10 kΩ or higher
G141-4 (+B1) - Body ground
Always
10 kΩ or higher
G141-3 (ACC1) - Body ground
Always
10 kΩ or higher
Table 4. Brake Actuator Assembly Tester Connection
Condition
Specified Condition
G87-1 (IG31) - A80-12 (IG1)
Always
Below 1 Ω
G87-1 (IG31) - Body ground
Always
10 kΩ or higher
A80-12 (IG1) - Body ground
Always
10 kΩ or higher
Table 5. Spiral with Sensor Cable Sub-assembly Tester Connection
Condition
Specified Condition
G87-1 (IG31) - G12-4 (IG)
Always
Below 1 Ω
G87-1 (IG31) - Body ground
Always
10 kΩ or higher
G12-4 (IG) - Body ground
Always
10 kΩ or higher
Table 6. Power Steering ECU Assembly Tester Connection
Condition
Specified Condition
G87-6 (IG11) - h1-1 (IG)
Always
Below 1 Ω
G87-6 (IG11) - Body ground
Always
10 kΩ or higher
h1-1 (IG) - Body ground
Always
10 kΩ or higher
Table 7. Combination Meter Assembly Tester Connection
Condition
Specified Condition
G87-10 (IG12) - G16-39 (IG+)
Always
Below 1 Ω
G87-10 (IG12) - Body ground
Always
10 kΩ or higher
G16-39 (IG+) - Body ground
Always
10 kΩ or higher
Table 8. Instrument Panel Junction Block Assembly (Main Body ECU (Multiplex Network Body ECU)) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - 3D-40 (IG)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
3D-40 (IG) - Body ground
Always
10 kΩ or higher
Table 9. Inner Rear View Mirror Assembly (w/ EC mirror without Lane Departure Alert System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - Q14-1 (IG)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
Q14-1 (IG) - Body ground
Always
10 kΩ or higher
Table 10. Inner Rear View Mirror Assembly (w/ EC mirror with Lane Departure Alert System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - Q15-4 (IG)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
Q15-4 (IG) - Body ground
Always
10 kΩ or higher
Table 11. Lane Departure Warning Camera (w/ Lane Departure Alert System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - Q17-7 (IGB)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
Q17-7 (IGB) - Body ground
Always
10 kΩ or higher
Table 12. Tire Pressure Warning ECU and Receiver (w/ Tire Pressure Warning System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - M30-1 (IG)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
M30-1 (IG) - Body ground
Always
10 kΩ or higher
Table 13. Blind Spot Monitor Sensor LH (w/ Blind Spot Monitor System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - R1-5 (BLB)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
R1-5 (BLB) - Body ground
Always
10 kΩ or higher
Table 14. Blind Spot Monitor Sensor RH (w/ Blind Spot Monitor System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - T1-5 (BRB)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
T1-5 (BRB) - Body ground
Always
10 kΩ or higher
Table 15. Network Gateway ECU Tester Connection
Condition
Specified Condition
G87-3 (IG41) - G170-11 (IG1)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
G170-11 (IG1) - Body ground
Always
10 kΩ or higher
Table 16. Millimeter Wave Radar Sensor Assembly (w/ Dynamic Radar Cruise Control System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - Z6-8 (IGB)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
Z6-8 (IGB) - Body ground
Always
10 kΩ or higher
Table 17. Driving Support ECU Assembly (w/ Dynamic Radar Cruise Control System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - G168-7 (B)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
G168-7 (B) - Body ground
Always
10 kΩ or higher
Table 18. Parking Assist ECU (w/ Panoramic View Monitor System) Tester Connection
Condition
Specified Condition
G87-3 (IG41) - a2-6 (IG)
Always
Below 1 Ω
G87-24 (AC41) - a2-1 (ACC)
Always
Below 1 Ω
G87-2 (B41) - a2-2 (+B)
Always
Below 1 Ω
G87-3 (IG41) - Body ground
Always
10 kΩ or higher
a2-6 (IG) - Body ground
Always
10 kΩ or higher
G87-24 (AC41) - Body ground
Always
10 kΩ or higher
a2-1 (ACC) - Body ground
Always
10 kΩ or higher
G87-2 (B41) - Body ground
Always
10 kΩ or higher
a2-2 (+B) - Body ground
Always
10 kΩ or higher
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE HARNESS OR CONNECTOR
CHECK ENGINE STOP AND START ECU (EACH ECU OR SENSOR POWER SOURCE CIRCUIT)
Disconnect the connector from the corresponding system ECU/sensor.
Measure the voltage according to the value(s) in the table below.
Tip:Measure the voltage at the corresponding terminals.
Standard Voltage
Table 19. Radio Receiver Assembly (for Radio Receiver Type) Tester Connection
Condition
Specified Condition
G46-4 (+B1) - Body ground
Always
10.5 to 16 V
Table 20. Navigation Receiver Assembly (for Navigation Receiver Type) Tester Connection
Condition
Specified Condition
G137-4 (+B1) - Body ground
Always
10.5 to 16 V
Table 21. Radio and Display Receiver Assembly (for Radio and Display Receiver Type) Tester Connection
Condition
Specified Condition
G141-4 (+B1) - Body ground
Always
10.5 to 16 V
Table 22. Parking Assist ECU (w/ Panoramic View Monitor System) Tester Connection
Condition
Specified Condition
a2-2 (+B) - Body ground
Always
10.5 to 16 V
Turn the ignition switch to ACC.
Measure the voltage according to the value(s) in the table below.
Tip:Measure the voltage at the corresponding terminals.
Standard Voltage
Table 23. Radio Receiver Assembly (for Radio Receiver Type) Tester Connection
Switch Condition
Specified Condition
G46-3 (ACC1) - Body ground
Ignition switch ACC
10.5 to 16 V
Table 24. Navigation Receiver Assembly (for Navigation Receiver Type) Tester Connection
Switch Condition
Specified Condition
G137-3 (ACC1) - Body ground
Ignition switch ACC
10.5 to 16 V
Table 25. Radio and Display Receiver Assembly (for Radio and Display Receiver Type) Tester Connection
Switch Condition
Specified Condition
G141-3 (ACC1) - Body ground
Ignition switch ACC
10.5 to 16 V
Table 26. Parking Assist ECU (w/ Panoramic View Monitor System) Tester Connection
Condition
Specified Condition
a2-1 (ACC) - Body ground
Ignition switch ACC
10.5 to 16 V
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
Tip:Measure the voltage at the corresponding terminals.
Standard Voltage
Tester Connection
Switch Condition
Specified Condition
3D-40 (IG) - Body ground
Ignition switch ON
10.5 to 16 V
Q14-1 (IG) - Body ground*1
Ignition switch ON
10.5 to 16 V
Q15-1 (IG) - Body ground*2
Ignition switch ON
10.5 to 16 V
M30-1 (IG) - Body ground*3
Ignition switch ON
10.5 to 16 V
G170-11 (IG1) - Body ground
Ignition switch ON
10.5 to 16 V
Z6-8 (IGB) - Body ground*4
Ignition switch ON
10.5 to 16 V
G168-7 (B) - Body ground*4
Ignition switch ON
10.5 to 16 V
Q17-7 (IGB) - Body ground*5
Ignition switch ON
10.5 to 16 V
R1-5 (BLB) - Body ground*6
Ignition switch ON
10.5 to 16 V
T1-5 (BRB) - Body ground*6
Ignition switch ON
10.5 to 16 V
a2-6 (IG) - Body ground*7
Ignition switch ON
10.5 to 16 V
G16-39 (IG+) - Body ground
Ignition switch ON
10.5 to 16 V
h1-1 (IG) - Body ground
Ignition switch ON
10.5 to 16 V
A80-12 (IG1) - Body ground
Ignition switch ON
10.5 to 16 V
G12-4 (IG) - Body ground
Ignition switch ON
10.5 to 16 V
*1: w/ EC Mirror without Lane Departure Alert System
*2: w/ EC Mirror with Lane Departure Alert System
*3: w/ Tire Pressure Warning System
*4: w/ Dynamic Radar Cruise Control System
*5: w/ Lane Departure Alert System
*6: w/ Blind Spot Monitor System
*7: w/ Panoramic View Monitor System
Result
Proceed to
OK
NG
OK CHECK POWER SOURCE CIRCUIT (POWER SOURCE CIRCUIT OF RELATED SYSTEM)
CHECK AUDIO AND VISUAL SYSTEM OR NAVIGATION SYSTEM
Turn the ignition switch off and wait for 1 minute.
Turn the ignition switch to ON.
Lower the audio volume.
for Radio Receiver Type/Radio and Display Receiver Type:
Check if the audio and visual system operates normally.
OK
Audio and visual system operates normally.
for Navigation Receiver Type:
Check if the navigation system operates normally.
OK
Navigation system operates normally.
Result
Proceed to
NG
OK
OK END
CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - RADIO AND DISPLAY RECEIVER)
Disconnect the G87 engine stop and start ECU connector.
for Radio Receiver Type:
Disconnect the G46 radio receiver assembly connector.
for Navigation Receiver Type:
Disconnect the G137 navigation receiver assembly connector.
for Radio and Display Receiver Type:
Disconnect the G141 radio and display receiver assembly connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Table 27. for Radio Receiver Type: Tester Connection
Condition
Specified Condition
G87-12 (B42) - Body ground
Always
10 kΩ or higher
G46-4 (+B1) - Body ground
Always
10 kΩ or higher
G87-24 (AC41) - Body ground
Always
10 kΩ or higher
G46-3 (ACC1) - Body ground
Always
10 kΩ or higher
Table 28. for Navigation Receiver Type: Tester Connection
Condition
Specified Condition
G87-12 (B42) - Body ground
Always
10 kΩ or higher
G137-4 (+B1) - Body ground
Always
10 kΩ or higher
G87-24 (AC41) - Body ground
Always
10 kΩ or higher
G137-3 (ACC1) - Body ground
Always
10 kΩ or higher
Table 29. for Radio and Display Receiver Type: Tester Connection
Condition
Specified Condition
G87-12 (B42) - Body ground
Always
10 kΩ or higher
G141-4 (+B1) - Body ground
Always
10 kΩ or higher
G87-24 (AC41) - Body ground
Always
10 kΩ or higher
G141-3 (ACC1) - Body ground
Always
10 kΩ or higher
Result
Proceed to
OK (for Radio Receiver Type/Radio and Display Receiver Type)
OK (for Navigation Receiver Type)
NG
OK (for Radio Receiver Type/Radio and Display Receiver Type) GO TO AUDIO AND VISUAL SYSTEM
for Radio Receiver Type:Click here
for Radio and Display Receiver Type:Click hereClick here
NG REPAIR OR REPLACE HARNESS OR CONNECTOR