This is the troubleshooting procedure for situations where the engine does not restart when attempting to restart it after a failed engine start occurred under stop and start system control.
PRECAUTIONS WHEN THE ENGINE STOP AND START ECU AND THE STARTER ASSEMBLY ARE REPLACED
When the engine stop and start ECU is replaced, it is necessary to read the number of starter operations before replacement and store this number in the new engine stop and start ECU after replacement, and to perform external backup boost converter (eco run vehicle converter assembly) existence learning. Moreover, initialization/learning of the air conditioning information and initialization/learning of the deceleration sensor zero point are also required.
When the starter assembly is replaced, the number of starter operations stored in the engine stop and start ECU must be reset.
When the starter assembly is replaced, "ST NO. 1 relay" must be also replaced.
Inspect the fuses for circuits related to this system before performing the following procedure.
PRECAUTIONS FOR FOUR-WHEEL TOWING
Do not tow the vehicle with all 4 wheels on the ground.
Towing the vehicle with all 4 wheels on the ground may have a detrimental effect on the stop and start system, and could lead to damage.
If it is absolutely necessary to tow the vehicle with all 4 wheels on the ground, before towing first turn the ignition switch off. Then, turn the ignition switch to ON without starting the engine, and tow the vehicle.
PRECAUTIONS WHEN REPLACING ECM
When the ECM is replaced on a vehicle with a non-specified battery, it is necessary to perform battery type switching.
Enter the following menus: Powertrain / Stop and Start / Utility / Vehicle Control History (RoB).
| Tester Display |
|---|
| Vehicle Control History (RoB) |
Check vehicle control history.
Checking the freeze frame data allows the vehicle conditions at the time of detection to be confirmed.
As Vehicle Control History may be overwritten whenever the trigger conditions are met, make sure to save the Vehicle Control History data before performing any inspections.
| Result | Proceed to |
|---|---|
| Vehicle control history [X0874: Stop & Start Restart Failure (Engine Restart after Engine Stall)] is output | A |
| Vehicle control history [X0874: Stop & Start Restart Failure (Engine Restart after Engine Stall)] is not output | B |
A
B
Diagnostic trouble code chart :
for M20C-FKS:
for M20D-FKS:
Click here
Vehicle control history (RoB):
for M20C-FKS:
for M20D-FKS:
Click here
Consult with the customer to determine if they performed operations that could result in an AT engine stall.
(ex.) Heavy load, frequent shifts, etc.
| Result | Proceed to |
|---|---|
| Driver operations that could cause engine stall were performed | A |
| None of the above conditions are met | B |
A
B
Enter the following menus: Powertrain / Stop and Start / Utility / Vehicle Control History (RoB).
| Tester Display |
|---|
| Vehicle Control History (RoB) |
Select a vehicle control history item to display the data from the time of control.
Check the output data.
Checking the freeze frame data allows the vehicle conditions at the time of detection to be confirmed.
As Vehicle Control History may be overwritten whenever the trigger conditions are met, make sure to save the Vehicle Control History data before performing any inspections.
| Result | Proceed to |
|---|---|
All recorded sections Starter Motor = OFF, and all recorded sections Engine Speed = 0 rpm
|
A |
Starter Motor = ON for any sections, and all recorded sections Engine Speed = 0 rpm
|
B |
Engine Speed > 0 rpm for any sections
|
C |
A
It is possible that there is a malfunction of the starter drive circuit inside the stop and start ECU.
B
C
Enter the following menus: Powertrain / Stop and Start / Utility / Vehicle Control History (RoB).
| Tester Display |
|---|
| Vehicle Control History (RoB) |
Select a vehicle control history item to display the data from the time of control.
Check the output data.
Checking the freeze frame data allows the vehicle conditions at the time of detection to be confirmed.
As Vehicle Control History may be overwritten whenever the trigger conditions are met, make sure to save the Vehicle Control History data before performing any inspections.
| Result | Proceed to |
|---|---|
Cranking Time is 1.5 seconds or more
|
A |
Cranking Time is less than 1.5 seconds
|
B |
A
B
Disconnect the engine stop and start ECU connector.
Turn the ignition switch to ON.
Turn off any electrical loads.
Measure the voltage according to the value(s) in the table below.
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| A34-1 (+B) - Body ground | Ignition switch ON | 11 V or higher |
| Proceed to |
|---|
| OK |
| NG |
OK
NG
Enter the following menus: Powertrain / Stop and Start / Utility / Vehicle Control History (RoB).
| Tester Display |
|---|
| Vehicle Control History (RoB) |
Select a vehicle control history item to display the data from the time of control.
Check the output data.
Checking the freeze frame data allows the vehicle conditions at the time of detection to be confirmed.
As Vehicle Control History may be overwritten whenever the trigger conditions are met, make sure to save the Vehicle Control History data before performing any inspections.
Depending on RoB detection timing, the minimum voltage from the previous startup will be stored for the Minimum Voltage (Cranking) and the Minimum Voltage (Starter Solenoid Engagement). For the battery condition at the start of the current driving cycle, see Battery Voltage.
When the value is 20 V, the value is being calculated.
| Result | Proceed to |
|---|---|
| Battery voltage is 8.92 V or more | A |
| Battery voltage is less than 8.92 V | B |
A
B
Measure the voltage of the battery.
11 to 14 V
| Proceed to |
|---|
| OK |
| NG |
OK
NG
Enter the following menus: Powertrain / Stop and Start / Utility / Vehicle Control History (RoB).
| Tester Display |
|---|
| Vehicle Control History (RoB) |
Select a vehicle control history to display the "Cranking Time" and "Starter OFF Permission History (ECM)" data from the time of control.
Check the output data.
Checking the freeze frame data allows the vehicle conditions at the time of detection to be confirmed.
As Vehicle Control History may be overwritten whenever the trigger conditions are met, make sure to save the Vehicle Control History data before performing any inspections.
| Result | Proceed to | |
|---|---|---|
| "Cranking Time" is less than 1.5 seconds | "Starter OFF Permission History (ECM)" is ON
|
A |
"Starter OFF Permission History (ECM)" is OFF
|
B | |
"Cranking Time" is 1.5 seconds or more
|
- | C |
A
for M20C-FKS:
for M20D-FKS:
Check whether the speed value of the EFI ECU is not a higher value than the original NE.
B
C
Enter the following menus: Powertrain / Stop and Start / Data List / Engine Speed and Engine Speed (ECM).
| Tester Display |
|---|
| Engine Speed |
| Engine Speed (ECM) |
Compare the Data List items displayed on the GTS.
| Result | Proceed to |
|---|---|
| Engine Speed > Engine Speed (ECM) + 100 rpm | A |
| None of the above conditions are met | B |
A
B
Enter the following menus: Powertrain / Stop and Start / Utility / Vehicle Control History (RoB).
| Tester Display |
|---|
| Vehicle Control History (RoB) |
Select a vehicle control history item to display the data from the time of control.
Check the data points in the data that was output.
Checking the freeze frame data allows the vehicle conditions at the time of detection to be confirmed.
As Vehicle Control History may be overwritten whenever the trigger conditions are met, make sure to save the Vehicle Control History data before performing any inspections.
| Result | Proceed to |
|---|---|
| For each and all of the data points, Engine Speed > Engine Speed (ECM) + 100 rpm | A |
| None of the above conditions are met | B |
A
B
| *a | Component with harness connected
(Engine Stop and Start ECU) |
- | - |
Enter the following menus: Powertrain / Stop and Start / Active Test / Starter (Hood Close)
| Tester Display |
|---|
| Starter(Hood Close) |
Measure the voltage according to the value(s) in the table below.
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A34-21 (STA) - A34-6 (DGND) | Performing Active Test, while cranking. | 6 to 14 V |
Using an oscilloscope, measure the waveform immediately after starting.
| Item | Content |
|---|---|
| Tester Connection | A34-21 (STA) - A34-6 (DGND) |
| Tool Setting | 10 V/DIV, 200 ms./DIV |
| Condition | During cranking |
Voltage and waveform both normal
| Proceed to |
|---|
| OK |
| NG |
OK
for M20C-FKS:
for M20D-FKS:
NG
| *a | Component with harness connected
(Engine Stop and Start ECU) |
- | - |
Enter the following menus: Powertrain / Stop and Start / Active Test / Starter (Hood Close)
| Tester Display |
|---|
| Starter(Hood Close) |
Measure the voltage according to the value(s) in the table below.
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A34-21 (STA) - A34-6 (DGND) | Performing Active Test, while cranking. | 6 to 14 V |
Using an oscilloscope, measure the waveform immediately after starting.
| Item | Content |
|---|---|
| Tester Connection | A34-21 (STA) - A34-6 (DGND) |
| Tool Setting | 10 V/DIV, 200 ms./DIV |
| Condition | During cranking |
Voltage and waveform both normal
| Proceed to |
|---|
| OK |
| NG |
OK
for M20C-FKS:
for M20D-FKS:
NG
Enter the following menus: Powertrain / Stop and Start / Utility / Vehicle Control History (RoB).
Select a vehicle control history item to display the data from the time of control.
Check the output data.
Checking the freeze frame data allows the vehicle conditions at the time of detection to be confirmed.
As Vehicle Control History may be overwritten whenever the trigger conditions are met, make sure to save the Vehicle Control History data before performing any inspections.
| Result | Proceed to |
|---|---|
| When Starter Motor is ON, there is even 1 point at which Engine Speed < 300 rpm | A |
| None of the above conditions are met | B |
A
B
Check how long it took the engine to stall after turning the starter off.
| Result | Proceed to |
|---|---|
After starter turned off, engine immediately stalls.
|
A |
| After starter turned off, engine stalls after a time. | B |
A
for M20C-FKS:
for M20D-FKS:
Check whether the speed value of the EFI ECU is not a higher value than the original NE.
B
for M20C-FKS:
for M20D-FKS:
Check whether the speed value of the EFI ECU is not a higher value than the original NE.