STOP AND START STOP AND START SYSTEM 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 from malfunctioning if the power source voltage drops due to the battery voltage dropping when the engine is restarted by stop and start control.
If any DTCs are output, troubleshoot the DTCs first.
- HINT:
-
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 signal.
- The backup boost converter supplies power to:·
Pre-Collision System
·Tire pressure warning system
·Electronically controlled brake system
·Power steering system
·Audio and visual system
·CAN communication system
·Meter / gauge system
·Air conditioning system
·Navigation System
WIRING DIAGRAM
Refer to DTC P323A19.
CAUTION / NOTICE / HINT
- NOTICE:
- ·
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 with ECU assembly, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.
·After replacing the engine stop and start ECU assembly, perform learning of the external backup boost converter (eco run vehicle converter assembly).
·Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
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 | Symptom | Proceed to |
|---|---|---|---|---|---|---|
| When the engine is restarted by stop and start control:
The following symptoms may occur ·
Audio and visual system is reset ·
The combination meter assembly fades out ·
The steering wheel feels heavy when the engine is restarted* ·
Navigation system is reset |
Backup boost converter internal malfunction
·
Internal power source malfunction ·
Internal power source overvoltage ·
CPU duty malfunction ·
Communication cycle error |
Stop and start control prohibited | P323A00
P323AA2 P323B29 P323B38 |
Blinks | Systems stop operating during engine restart as the backup boost converter output voltage cannot be boosted | A |
| Battery voltage drop | ||||||
| Systems on the converter output side do not operate
B41 terminal: Tire pressure warning system will not operate B42 terminal: Both of the following will not operate ·
Audio and visual system ·
Navigation system IG41 terminal: All of the following will not operate ·
Pre-collision system ·
Tire pressure warning system ·
CAN communication system ·
Air conditioning system |
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) |
P323A19 | 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 will not operate ·
Pre-collision system ·
Tire pressure warning system ·
Electronically controlled brake system ·
Power steering system ·
CAN communication system ·
Air conditioning system IG2 terminal: The meter / gauge system will not operate ACC terminal: Both of the following will not operate ·
Audio and visual system ·
Navigation system |
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: Both of the following will not operate ·
Audio and visual system ·
Navigation system IG11 terminal: The power steering system will not operate IG12 terminal: The meter / gauge system will not operate IG31 terminal: Both of the following will not operate ·
power steering system ·
Electronically controlled brake system IG41 terminal: All of the following will not operate ·
Pre-collision system ·
Tire pressure warning system ·
CAN communication system ·
Air conditioning system B41 terminal: Tire pressure warning system will not operate B42 terminal: Both of the following will not operate ·
Audio and visual system ·
Navigation system |
Malfunction in circuits the converter supplies power to
(between the converter and ECUs or sensors) |
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 systems do not operate
·
Pre-Collcision system ·
Tire pressure warning system ·
Electronically controlled brake system ·
Power steering system ·
Audio and visual system ·
Navigation system ·
CAN communication system ·
Meter / gauge system ·
Air conditioning system |
·
Open in BBC fuse circuit ·
Short in converter circuit ·
Backup boost converter malfunction |
Stop and start control prohibited | P061519 | Does not blink (Due to disabled meter / gauge system) | All systems that the converter supplies power to do not operate (see circuit diagram) | A |
| P30DF62
P30EF48 P323A00 P323A16 P323AA2 P323B29 P323B38 |
||||||
| The audio does not operate
(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 (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 (navigation system), system operation is disabled while the ignition switch is ON
(Returns to normal when the ignition switch is turned off) |
C |
·
The combination meter assembly cannot be turned off (short between IG12 and +B) ·
Communication error DTCs may be stored due to short between AC41 and +B
|
Converter circuit malfunction
·
Short between IG12 and +B ·
Short between AC41 and +B |
- | - | Does not blink | The converter cannot shut off the power source when the ignition switch is turned off | B |
·
Ignition switch cannot be turned off from ACC (short between ACC and +B) ·
Ignition switch cannot be turned off from IG (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 cannot be turned off | B |
*: A DTC may be stored in the power steering system
- Result:
Proceed to A B C
A
B
C
| *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 A123-1 (BIN2) - Body ground Always 9.5 to 14 V A123-3 (BIN1) - Body ground Always 9.5 to 14 V
- Result:
Proceed to OK NG
OK
NG
| *a | Front view of wire harness connector
(to Engine Stop and Start ECU) |
Disconnect the engine stop and start ECU connector.
Turn the ignition switch to ACC.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Condition Specified Condition I58-19 (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 I58-21 (IG1) - Body ground Ignition switch ON 9.5 to 14 V
Turn the ignition switch to off.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Condition Specified Condition I58-19 (ACC) - Body ground Ignition switch off 0 to 1 V I58-21 (IG1) - Body ground Ignition switch off 0 to 1 V
- Result:
Proceed to OK NG
OK
NG
| *a | Front view of wire harness connector
(to Engine Stop and Start ECU) |
Disconnect the engine stop and start ECU connector.
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 A124-1 (+B) - Body ground Ignition switch ON 9.5 to 14 V
Turn the ignition switch to off.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Condition Specified Condition A124-1 (+B) - Body ground Ignition switch off 0 to 1 V
- Result:
Proceed to OK NG
OK
NG
Disconnect the connector from the corresponding system ECU/sensor.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tire Pressure Warning ECU and Receiver (w/ Tire Pressure Warning System and Smart Entry and Start System) Tester Connection Condition Specified Condition I58-2 (B41) - O18-7 (+B) Always Below 1 Ω I58-3 (IG41) - O18-1 (IG) Always Below 1 Ω I58-2 (B41) or O18-7 (+B) - Body ground and other terminals Always 10 kΩ or higher I58-3 (IG41) or O18-1 (IG) - Body ground and other terminals Always 10 kΩ or higher
Tire Pressure Warning ECU and Receiver (w/ Tire Pressure Warning System without Smart Entry and Start System) Tester Connection Condition Specified Condition I58-2 (B41) - O124-7 (+B) Always Below 1 Ω I58-3 (IG41) - O124-1 (IG) Always Below 1 Ω I58-2 (B41) or O124-7 (+B) - Body ground and other terminals Always 10 kΩ or higher I58-3 (IG41) or O124-1 (IG) - Body ground and other terminals Always 10 kΩ or higher
Radio and Display Receiver Assembly (for Radio and Display Receiver Type) Tester Connection Condition Specified Condition I58-12 (B42) - I165-4 (+B1) Always Below 1 Ω I58-24 (AC41) - I165-3 (ACC1) Always Below 1 Ω I58-12 (B42) or I165-4 (+B1) - Body ground and other terminals Always 10 kΩ or higher I58-24 (AC41) or I165-3 (ACC1) - Body ground and other terminals Always 10 kΩ or higher
Navigation Receiver Assembly (for Navigation Receiver Type (w/ RST Switch)) Tester Connection Condition Specified Condition I58-12 (B42) - I167-4 (+B1) Always Below 1 Ω I58-24 (AC41) - I167-3 (ACC1) Always Below 1 Ω I58-12 (B42) or I167-4 (+B1) - Body ground and other terminals Always 10 kΩ or higher I58-24 (AC41) or I167-3 (ACC1) - Body ground and other terminals Always 10 kΩ or higher
Navigation Receiver Assembly (for Navigation Receiver Type (w/o RST Switch)) Tester Connection Condition Specified Condition I58-12 (B42) - I187-15 (+B1) Always Below 1 Ω I58-24 (AC41) - I187-16 (ACC1) Always Below 1 Ω I58-12 (B42) or I187-15 (+B1) - Body ground and other terminals Always 10 kΩ or higher I58-24 (AC41) or I187-16 (ACC1) - Body ground and other terminals Always 10 kΩ or higher
Central Gateway ECU (Network Gateway ECU) Tester Connection Condition Specified Condition I58-3 (IG41) - I53-11 (IG1) Always Below 1 Ω I58-3 (IG41) or I53-11 (IG1) - Body ground and other terminals Always 10 kΩ or higher
Skid Control ECU (Brake Actuator Assembly) Tester Connection Condition Specified Condition I58-1 (IG31) - A51-36 (IG1) Always Below 1 Ω I58-1 (IG31) or A51-36 (IG1) - Body ground and other terminals Always 10 kΩ or higher
Millimeter Wave Radar Sensor Assembly (w/ Pre-Collision System) Tester Connection Condition Specified Condition I58-3 (IG41) - A1-8 (IGB) Always Below 1 Ω I58-3 (IG41) or A1-8 (IGB) - Body ground and other terminals Always 10 kΩ or higher
Air Conditioning Control Assembly (for Radio & Display Receiver Type and for Radio Receiver Type) Tester Connection Condition Specified Condition I58-3 (IG41) - I37-9 (IG+) Always Below 1 Ω I58-3 (IG41) or I37-9 (IG+) - Body ground and other terminals Always 10 kΩ or higher
Air Conditioning Control Assembly (for Navigation Receiver Type) Tester Connection Condition Specified Condition I58-3 (IG41) - I147-8 (IG+) Always Below 1 Ω I58-3 (IG41) or I147-8 (IG+) - Body ground and other terminals Always 10 kΩ or higher
Steering Sensor Tester Connection Condition Specified Condition I58-1 (IG31) - I46-9 (IG1) Always Below 1 Ω I58-1 (IG31) or I46-9 (IG1) - Body ground and other terminals Always 10 kΩ or higher
Power Steering ECU Tester Connection Condition Specified Condition I58-6 (IG11) - I21-1 (IG) Always Below 1 Ω I58-6 (IG11) or I21-1 (IG) - Body ground and other terminals Always 10 kΩ or higher
Combination Meter Assembly Tester Connection Condition Specified Condition I58-10 (IG12) - I4-38 (IG+) Always Below 1 Ω I58-10 (IG12) or I4-38 (IG+) - Body ground and other terminals Always 10 kΩ or higher
- Result:
Proceed to OK NG
OK
NG
Disconnect the connector from the corresponding system ECU/sensor.
Measure the voltage according to the value(s) in the table below.
- HINT:
-
Measure the voltage at the corresponding terminals.
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| O18-7 (+B) - Body ground*1*3 | Always | 10.5 to 16 V |
| O124-7 (+B) - Body ground*1*4 | Always | 10.5 to 16 V |
| I165-4 (+B1) - Body ground*2 | Always | 10.5 to 16 V |
| I167-4 (+B1) - Body ground*5 | Always | 10.5 to 16 V |
| I187-15 (+B1) - Body ground*6 | Always | 10.5 to 16 V |
*1: w/ Tire Pressure Warning System
*2: for Radio and Display Receiver Type
*3: w/ Smart Entry and Start System
*4: w/o Smart Entry and Start System
*5: for Navigation Receiver Type (w/ RST Switch)
*6: for Navigation Receiver Type (w/o RST Switch)
Turn the ignition switch to ACC.
Measure the voltage according to the value(s) in the table below.
- HINT:
-
Measure the voltage at the corresponding terminals.
- Standard Voltage:
Tester Connection Condition Specified Condition I165-3 (ACC1) - Body ground*1 Ignition switch ACC 10.5 to 16 V I167-3 (ACC1) - Body ground*2 Ignition switch ACC 10.5 to 16 V I187-16 (ACC1) - Body ground*3 Ignition switch ACC 10.5 to 16 V
*1: for Radio and Display Receiver Type
*2: for Navigation Receiver Type (w/ RST Switch)
*3: for Navigation Receiver Type (w/o RST Switch)
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- HINT:
-
Measure the voltage at the corresponding terminals.
- Standard Voltage:
Tester Connection Condition Specified Condition O18-1 (IG) - Body ground*1*3 Ignition switch ON 10.5 to 16 V O124-1 (IG) - Body ground*1*4 Ignition switch ON 10.5 to 16 V I53-11 (IG1) - Body ground Ignition switch ON 10.5 to 16 V A1-8 (IGB) - Body ground*2 Ignition switch ON 10.5 to 16 V I37-9 (IG+) - Body ground*5 Ignition switch ON 10.5 to 16 V I147-8 (IG+) - Body ground*6 Ignition switch ON 10.5 to 16 V A51-36 (IG1) - Body ground Ignition switch ON 10.5 to 16 V I46-9 (IG1) - Body ground Ignition switch ON 10.5 to 16 V I21-1 (IG) - Body ground Ignition switch ON 10.5 to 16 V I4-38 (IG+) - Body ground Ignition switch ON 10.5 to 16 V
*1: w/ Tire Pressure Warning System
*2: w/ Front Radar Sensor System
*3: w/ Smart Entry and Start System
*4: w/o Smart Entry and Start System
*5: except 12.1 Inch Display Type
*6: for 12.1 Inch Display Type
- Result:
Proceed to OK NG
OK
NG
Turn the ignition switch off and wait for 1 minute.
Turn the ignition switch to ON.
Lower the audio volume.
Check if the audio and visual system operates normally.
- OK:
Audio and visual system operates normally.
- Result:
Proceed to OK NG
OK
NG
Disconnect the engine stop and start ECU connector.
Disconnect the radio and display receiver assembly connector. (for Radio and Display Receiver Type)
Disconnect the navigation receiver assembly connector. (for Navigation Receiver Type)
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition I58-12 (B42) or I167-4 (+B1)*1 - Body ground Always 10 kΩ or higher I58-12 (B42) or I187-4 (+B1)*2 - Body ground Always 10 kΩ or higher I58-12 (B42) or I165-4 (+B1)*3 - Body ground Always 10 kΩ or higher
*1: for Navigation Receiver Type (w/ RST Switch)
*2: for Navigation Receiver Type (w/o RST Switch)
*3: for Radio and Display Receiver Type
- Result:
Result Proceed to OK (for Navigation Receiver Type) A OK (for Radio and Display Receiver Type) B NG C
A
B
C