SMART ENTRY AND START SYSTEM(for Start Function) Engine does not Start

DESCRIPTION

When the electrical key transmitter sub-assembly is in the cabin and the engine switch is pressed, the certification ECU (smart key ECU assembly) receives a signal and changes the power source mode. Additionally, when the shift lever is in P and the brake pedal is depressed, the engine can be started by pressing the engine switch. If the steering is unlocked, the engine can also be started by pressing the engine switch with the shift lever in N and the brake pedal depressed.

Related Data List and Active Test Items
Problem Symptom	Data List and Active Test
Engine does not start	Power Source Control Stop Light Switch1 Steering Unlock Switch Shift P Signal Neutral SW/ Clutch SW IG Relay Monitor (Inside) IG Relay Monitor (Outside) Latch Circuit Starter Request Signal Power Supply Condition Entry&Start Immobiliser Engine Start Request L Code Check Starting Control Starter SW Shift Position P or N Ignition

WIRING DIAGRAM

CAUTION / NOTICE / HINT

Note

When using the GTS with the engine switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select Model Code "KEY REGIST" under manual mode and enter the following menus: Body Electrical / Entry&Start(CAN). While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.
The smart entry and start system (for Start Function) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart entry and start system (for Start Function) after confirming that the communication systems are functioning properly.

Click here
If the smart entry and start system (for Start Function) has been disabled, enable the system before performing troubleshooting.

Click here
Inspect the fuses for circuits related to this system before performing the following procedure.
Before replacing the certification ECU (smart key ECU assembly) or an electrical key transmitter sub-assembly, refer to Service Bulletin.
After completing repairs, confirm that the problem does not recur.
After performing repairs, confirm that no DTCs are output by performing "DTC Output Confirmation Operation."

Tech Tips

If the engine switch is changed from on (IG) to on (ACC) with the shift lever in any position other than P, and then the shift lever is moved to P and the engine switch is pressed with the brake pedal depressed, the engine switch will turn off.
If the brake pedal is repeatedly depressed while the engine is stopped, the brake booster pressure will be released and the force required to depress the brake pedal to illuminate the stop lights will increase.

PROCEDURE

CHECK ENGINE CRANKING OPERATION

Get into the vehicle while carrying an electrical key transmitter sub-assembly.
Move the shift lever to P.

Check that the key indicator display is displayed on the multi-information display in the combination meter assembly, and then press the engine switch and check that the engine cranks.

Result

Result	Proceed to
Engine cranks and initial combustion occurs	A
Engine cranks but initial combustion does not occur	B
Engine does not crank	C

GO TO OTHER PROBLEM (Immobiliser System does not Operate Properly) Click here

GO TO SFI SYSTEM for A25A-FKS: Click here
GO TO SFI SYSTEM for 2GR-FKS: Click here
GO TO SFI SYSTEM for 2AR-FE: Click here

CHECK ENGINE SWITCH CONDITION

Get into the vehicle while carrying an electrical key transmitter sub-assembly.
Move the shift lever to P.

With the brake pedal released, check that pressing the engine switch causes the power source mode to change.

Result

Result	Proceed to
Power source mode changes : Off → on (ACC) → on (IG) → off	A
Power source mode does not change to on (ACC) or on (IG)	B
Power source mode changes to on (IG) but not to on (ACC)	C
Power source mode changes to on (ACC) but not to on (IG)	D

GO TO OTHER PROBLEM (Power Source Mode does not Change to ON (IG and ACC)) Click here

GO TO OTHER PROBLEM (Power Source Mode does not Change to ON (ACC)) Click here

GO TO OTHER PROBLEM (Power Source Mode does not Change to ON (IG)) Click here

READ VALUE USING GTS (STOP LIGHT SWITCH1)

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Body Electrical / Power Source Control / Data List.

Read the Data List according to the display on the GTS.

Body Electrical > Power Source Control > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light Switch1	State of brake pedal	OFF or ON	OFF: Brake pedal released ON: Brake pedal depressed	Use this item to determine if the stop light switch assembly is malfunctioning. The engine cannot be started when this item is OFF. If the stop light switch assembly is malfunctioning, the engine can be started by pressing and holding the engine switch for a certain period of time.

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Stop Light Switch1

State of brake pedal

OFF or ON

OFF: Brake pedal released

ON: Brake pedal depressed

Use this item to determine if the stop light switch assembly is malfunctioning.
The engine cannot be started when this item is OFF.
If the stop light switch assembly is malfunctioning, the engine can be started by pressing and holding the engine switch for a certain period of time.

Body Electrical > Power Source Control > Data List

Tester Display
Stop Light Switch1

OK
The GTS display changes correctly in response to the brake pedal operation.

Result

Proceed to
OK
NG

INSPECT STOP LIGHT SWITCH ASSEMBLY Click here

READ VALUE USING GTS (NEUTRAL SW/ CLUTCH SW, SHIFT POSITION P OR N)

Enter the following menus: Body Electrical / Power Source Control or Starting Control / Data List.

Read the Data List according to the display on the GTS.

Body Electrical > Power Source Control > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Neutral SW/ Clutch SW	Shift position (P and N)	OFF or ON	OFF: Shift lever in any position other than P or N ON: Shift lever in P or N	Use this item to determine if the park/neutral position switch assembly is malfunctioning. When the engine cannot be started due to a park/neutral position switch assembly malfunction, OFF is displayed.

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Neutral SW/ Clutch SW

Shift position (P and N)

OFF or ON

OFF: Shift lever in any position other than P or N

ON: Shift lever in P or N

Use this item to determine if the park/neutral position switch assembly is malfunctioning.
When the engine cannot be started due to a park/neutral position switch assembly malfunction, OFF is displayed.

Body Electrical > Power Source Control > Data List

Tester Display
Neutral SW/ Clutch SW

Body Electrical > Starting Control > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Shift Position P or N	Park/Neutral position switch status	OFF or ON	OFF: Shift lever not in P or N ON: Shift lever in P or N	When OFF is displayed, the engine will not crank.

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Shift Position P or N

Park/Neutral position switch status

OFF or ON

OFF: Shift lever not in P or N

ON: Shift lever in P or N

When OFF is displayed, the engine will not crank.

Body Electrical > Starting Control > Data List

Tester Display
Shift Position P or N

OK
The GTS display changes correctly in response to the shift lever operation.

Result

Proceed to
OK
NG

INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY Click here

READ VALUE USING GTS (STARTER REQUEST SIGNAL)

Enter the following menus: Body Electrical / Power Source Control / Data List.

Read the Data List according to the display on the GTS.

Body Electrical > Power Source Control > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Starter Request Signal	Engine start request signal status	OFF or ON	OFF: The engine switch is not pressed ON: With the shift lever in P and the brake pedal depressed, the engine switch is pressed and held	When the engine cannot be started due to a start request signal malfunction, OFF is displayed. When the engine switch is pressed, the duration of time that ON is displayed will be extremely short. As such, the engine switch needs to be pressed and held for a certain period of time.

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Starter Request Signal

Engine start request signal status

OFF or ON

OFF: The engine switch is not pressed

ON: With the shift lever in P and the brake pedal depressed, the engine switch is pressed and held

When the engine cannot be started due to a start request signal malfunction, OFF is displayed.
When the engine switch is pressed, the duration of time that ON is displayed will be extremely short. As such, the engine switch needs to be pressed and held for a certain period of time.

Body Electrical > Power Source Control > Data List

Tester Display
Starter Request Signal

Note

Check that the key indicator display is displayed on the multi-information display in the combination meter assembly, and then press the engine switch.

OK
The GTS display changes correctly in response to the engine switch operation.

Result

Proceed to
OK
NG

CHECK STEERING LOCK FUNCTION Click here

READ VALUE USING GTS (STARTER SW)

Get into the vehicle while carrying an electrical key transmitter sub-assembly.
Move the shift lever to P.
Enter the following menus: Body Electrical / Starting Control / Data List.

According to the display on the GTS, read the Data List while pressing the engine switch with the brake pedal depressed.

Body Electrical > Starting Control > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Starter SW	Starter operation request	OFF or ON	OFF: Starter operation not requested ON: Starter operation requested	When OFF is displayed, the engine will not crank.

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Starter SW

Starter operation request

OFF or ON

OFF: Starter operation not requested

ON: Starter operation requested

When OFF is displayed, the engine will not crank.

Body Electrical > Starting Control > Data List

Tester Display
Starter SW

OK
The GTS display changes.

Result

Proceed to
OK
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

INSPECT ST RELAY

Inspect the ST relay.

for A25A-FKS: Click here

for 2GR-FKS: Click here

for 2AR-FE: Click here

Result

Proceed to
OK
NG

REPLACE ST RELAY

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ST RELAY)

*1	ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (ST Relay Holder)

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
Engine room relay block and junction block assembly ST relay terminal 2 - Body ground	Engine switch pressed and held with brake pedal depressed (starter on) → Approximately 1 second after engine switch released (starter off)	6 V or higher* → 1.0 V or less

Tech Tips

*: While the engine is cranking, the battery voltage may drop to approximately 6 V.

Result

Proceed to
OK
NG

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Click here

CHECK HARNESS AND CONNECTOR (ST RELAY - BATTERY AND GROUND)

*1	ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (ST Relay Holder)

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
Engine room relay block and junction block assembly ST relay terminal 1 - Body ground	Always	Below 1 Ω

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
Engine room relay block and junction block assembly ST relay terminal 5 - Body ground	Always	11 to 14 V

Result

Proceed to
OK
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK HARNESS AND CONNECTOR (STARTER ASSEMBLY - ST RELAY)

Disconnect the C64*1 or C61*2 starter assembly connector.
- *1: for A25A-FKS
- *2: except A25A-FKS

Measure the resistance according to the value(s) in the table below.

Standard Resistance

for A25A-FKS
Tester Connection	Condition	Specified Condition
Engine room relay block and junction block assembly ST relay terminal 3 - C64-1	Always	Below 1 Ω
Engine room relay block and junction block assembly ST relay terminal 3 or C64-1 - Other terminals and body ground	Always	10 kΩ or higher

except A25A-FKS
Tester Connection	Condition	Specified Condition
Engine room relay block and junction block assembly ST relay terminal 3 - C61-1	Always	Below 1 Ω
Engine room relay block and junction block assembly ST relay terminal 3 or C61-1 - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK HARNESS AND CONNECTOR (STARTER ASSEMBLY - BATTERY)

Disconnect the D1*1 or C74*2 starter assembly connector.
- *1: for A25A-FKS
- *2: except A25A-FKS

Measure the voltage according to the value(s) in the table below.

Standard Voltage

for A25A-FKS
Tester Connection	Condition	Specified Condition
D1-1 - Body ground	Always	11 to 14 V

except A25A-FKS
Tester Connection	Condition	Specified Condition
C74-1 - Body ground	Always	11 to 14 V

Result

Proceed to
OK
NG

REPLACE STARTER ASSEMBLY for A25A-FKS: Click here
REPLACE STARTER ASSEMBLY for 2GR-FKS: Click here
REPLACE STARTER ASSEMBLY for 2AR-FE: Click here

REPAIR OR REPLACE HARNESS OR CONNECTOR

INSPECT STOP LIGHT SWITCH ASSEMBLY

Inspect the stop light switch assembly.

Click here

Result

Proceed to
OK
NG

REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STOP LIGHT SWITCH ASSEMBLY)

Disconnect the A37 stop light switch assembly connector.
Disconnect the R8 certification ECU (smart key ECU assembly) connector.
Disconnect the A24*1, A23*2 or A22*3 ECM connector.
Disconnect the A34 skid control ECU (brake actuator assembly) connector.
Disconnect the K27 shift lock control unit assembly connector.
- *1: for A25A-FKS
- *2: for 2GR-FKS
- *3: for 2AR-FE

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
R8-25 (STP1) - A37-3 (L)	Always	Below 1 Ω
R8-25 (STP1) or A37-3 (L) - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR

INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY

Remove the park/neutral position switch assembly.

for UB80E: Click here

for UA80E: Click here

for U760E: Click here

Inspect the park/neutral position switch assembly.

for UB80E: Click here

for UA80E: Click here

for U760E: Click here

Result

Proceed to
OK
NG

REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY for UB80E: Click here
REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY for UA80E: Click here
REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY for U760E: Click here

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - PARK/NEUTRAL POSITION SWITCH ASSEMBLY)

Disconnect the A13 certification ECU (smart key ECU assembly) connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
A13-9 (STAR) - C55-4 (B)	Always	Below 1 Ω
A13-9 (STAR) or C55-4 (B) - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK STEERING LOCK FUNCTION

Check that the steering unlocks when the engine switch is turned on (ACC).

OK
The steering unlocks.

Result

Proceed to
OK
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

GO TO OTHER PROBLEM (Unable to Unlock Steering Wheel (Engine cannot Start)) Click here

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

*a	Component with harness connected (Certification ECU (Smart Key ECU Assembly))

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
A13-9 (STAR) - Body ground	Engine switch pressed and held with brake pedal depressed (starter on) → Approximately 1 second after engine switch released (starter off)	6 V or higher* → 1.0 V or less

Tech Tips

*: While the engine is cranking, the battery voltage may drop to approximately 6 V.

Result

Proceed to
OK
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - PARK/NEUTRAL POSITION SWITCH ASSEMBLY)

Disconnect the A13 certification ECU (smart key ECU assembly) connector.
Disconnect the C55 park/neutral position switch assembly connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
A13-9 (STAR) - C55-4 (B)	Always	Below 1 Ω
A13-9 (STAR) or C55-4 (B) - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Install the ST relay to the engine room relay block and junction block assembly.

*a	Component with harness connected (Certification ECU (Smart Key ECU Assembly))

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
A13-20 (STA) - Body ground	Engine switch pressed and held with brake pedal depressed (starter on) → Approximately 1 second after engine switch released (starter off)	6 V or higher* → 1.0 V or less

Tech Tips

*: While the engine is cranking, the battery voltage may drop to approximately 6 V.

Result

Proceed to
OK
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ST RELAY)

Disconnect the A13 certification ECU (smart key ECU assembly) connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
A13-20 (STA) - 2 (ST relay)	Always	Below 1 Ω
A13-20 (STA) or 2 (ST relay) - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ST RELAY)

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
C55-9 (L) - 2 (ST relay)	Always	Below 1 Ω
C55-9 (L) or 2 (ST relay) - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

GO TO SFI SYSTEM for A25A-FKS: Click here
GO TO SFI SYSTEM for 2GR-FKS: Click here
GO TO SFI SYSTEM for 2AR-FE: Click here

REPAIR OR REPLACE HARNESS OR CONNECTOR