STOP AND START SYSTEM(for 3ZR-FAE), Diagnostic DTC:P1540
| DTC Code | DTC Name |
|---|---|
| P1540 | Brake Booster Sensor Circuit (Open or Short) |
DESCRIPTION
The engine stop and start ECU determines changes in the brake booster assembly pressure based on the voltage signal received from the vacuum sensor assembly in the brake booster assembly.
If the engine stop and start ECU judges that the signal received from the vacuum sensor assembly is abnormal, it stores DTC P1540 and blinks the stop and start cancel indicator light.
DTC No. |
Detection Item |
DTC Detection Condition |
Trouble Area |
Warning Indicate |
Memory |
|---|---|---|---|---|---|
P1540 |
Brake Booster Sensor Circuit (Open or Short) |
Both of the following conditions are met for 2 seconds or more (1 trip detection logic):
|
|
Blinks |
DTC stored |
CONFIRMATION DRIVING PATTERN
DTCs for the stop and start system are not cleared even if the malfunction has been repaired. After repairing the malfunction, be sure to clear the DTCs.
CONFIRMATION AFTER TROUBLESHOOTING
Tip:If the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited until refresh charge is completed. In this case, drive the vehicle approximately 5 to 40 minutes until refresh charge is completed and stop and start control operation is permitted.
Allow the engine to idle for 3 minutes after it is warmed up and check that the engine idle speed is within 50 rpm of the target idle speed.
Connect the GTS to the DLC3.
Turn the ignition switch to ON and turn the GTS on.
Clear the DTCs.
Powertrain > Stop and Start > Clear DTCs
Start the engine and allow it to idle for 15 seconds or more.
Stop the engine and turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Stop and Start / Data List / Brake Boost Pressure.
Powertrain > Stop and Start > Data List
Tester Display
Brake Boost Pressure
While depressing the brake pedal several times, check that the Brake Boost Pressure value changes.
Check that DTCs are not output.
Powertrain > Stop and Start > Trouble Codes
STOP AND START SYSTEM OPERATION CHECK
Tip:If the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited until refresh charge is completed. In this case, drive the vehicle approximately 5 to 40 minutes until refresh charge is completed and stop and start control operation is permitted.
Start the engine and warm it up.
Turn the air conditioning system off.
Drive the vehicle at 7 km/h (4.3 mph) or more.
CAUTION:When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.
Depress the brake pedal and stop the vehicle.
Allow the engine to stop by stop and start control. (Keep the shift lever in D.)
Release the brake pedal with the shift lever in D to start the engine.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
When replacing the engine stop and start ECU with a new one, make sure to download the previous status (number of starter operations) of the old engine stop and start ECU. After replacing the engine stop and start ECU, turn the ignition switch to ON and wait 20 seconds, then confirm that "OK" is displayed for the Data List item "Oper Prohibition (O/P Air Bleeding)". Then upload the previous status (number of starter operations) to the 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.
Using the GTS, read the freeze frame data before troubleshooting. System condition information is recorded as freeze frame data the moment a DTC is stored. This information can be useful when troubleshooting.
PROCEDURE
CHECK VACUUM SENSOR ASSEMBLY (PB TERMINAL VOLTAGE)
*a
Component with harness connected
(Engine Stop and Start ECU)
-
-
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
A66-13 (PB) - A66-3 (BRE2)
Ignition switch ON
Higher than 0.6 V or below 4.7 V
Result
Proceed to
OK
NG
CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - VACUUM SENSOR ASSEMBLY)
Disconnect the A66 engine stop and start ECU connector.
Disconnect the A60 vacuum sensor assembly connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
A66-13 (PB) - A60-2 (PB)
Always
Below 1 Ω
A66-14 (BRVC) - A60-3 (VC)
Always
Below 1 Ω
A66-3 (BRE2) - A60-1 (E2)
Always
Below 1 Ω
A66-13 (PB) - Body ground
Always
10 kΩ or higher
A66-14 (BRVC) - Body ground
Always
10 kΩ or higher
A66-3 (BRE2) - Body ground
Always
10 kΩ or higher
A60-2 (PB) - Body ground
Always
10 kΩ or higher
A60-3 (VC) - Body ground
Always
10 kΩ or higher
A60-1 (E2) - 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 (BRVC TERMINAL VOLTAGE)
*a
Component with harness connected
(Engine Stop and Start ECU)
-
-
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
A66-14 (BRVC) - A66-3 (BRE2)
Ignition switch ON
4.75 to 5.25 V
Result
Proceed to
OK
NG
REPLACE VACUUM SENSOR ASSEMBLY
Replace the vacuum sensor assembly.
Result
Proceed to
NEXT
CHECK DTC OUTPUT
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Stop and Start / Trouble Codes.
Check that no DTCs are output.
Powertrain > Stop and Start > Trouble Codes
Result
Result
Proceed to
DTCs are not output
A
DTC P1540 is output
B
A END