Engine does not Start [12/2019 - 10/2021]: Procedure

1. Get into the vehicle while carrying an electrical key transmitter sub-assembly.
2. Move the shift lever to P.
3. 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

Result: 

A 

GO TO OTHER PROBLEM (Immobilizer System does not Operate Properly). Refer to  Immobilizer System does not Operate Properly [12/2019 - 10/2021] 

Result: 

B 

GO TO SFI SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2022] 

Result: 

C 

See step  2

1. Get into the vehicle while carrying an electrical key transmitter sub-assembly.
2. Move the shift lever to P.
3. 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 → ACC → ON → off	A
   Power source mode does not change to ACC or ON	B
   Power source mode changes to ON but not to ACC	C
   Power source mode changes to ACC but not to ON	D

Result: 

B 

GO TO OTHER PROBLEM (Power Source Mode does not Change to ON (IG and ACC)). Refer to  Power Source Mode does not Change to ON (IG and ACC) [12/2019 - 10/2022]  

Result: 

C 

GO TO OTHER PROBLEM (Power Source Mode does not Change to ON (ACC)). Refer to  Power Source Mode does not Change to ON (ACC) [12/2019 - 11/2023] 

Result: 

D 

GO TO OTHER PROBLEM (Power Source Mode does not Change to ON (IG)). Refer to  Power Source Mode does not Change to ON (IG) [12/2019 - 11/2023] 

Result: 

A 

See step  3

1. 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.

   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

Result: 

NG 

See step  12

Result: 

OK 

See step  4

1. 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.

   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.

   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

Result: 

NG 

See step  14

Result: 

OK 

See step  5

1. 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.

   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

Result: 

NG 

See step  16

Result: 

OK 

See step  6

1. Get into the vehicle while carrying an electrical key transmitter sub-assembly.
2. Move the shift lever to P.
3. 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.

   Body Electrical > Starting Control > Data List 

   Tester Display
   Starter SW

   OK

   The GTS display changes.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

OK 

See step  7

Refer to INSPECTION [12/2019 - 10/2022]

Result

Result: 

NG 

REPLACE ST RELAY 

Result: 

OK 

See step  8

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   No. 1 engine room relay block and No. 1 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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly (ST Relay Holder)

   HINT: 

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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  17

Result: 

OK 

See step  9

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 1 - Body ground	Always	Below 1 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly (ST Relay Holder)

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 5 - Body ground	Always	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  10

1. Disconnect the C56 starter assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 3 - C56-1	Always	Below 1 Ω
   No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 3 or C56-1 - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  11

1. Disconnect the C69 starter assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   C69-1 - Body ground	Always	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE STARTER ASSEMBLY 

w/ Stop and Start System: Refer to REMOVAL [12/2019 - 09/2020] , or refer to REMOVAL [09/2020 - 10/2022]

w/o Stop and Start System: Refer to REMOVAL [12/2019 - 10/2022]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Refer to ON-VEHICLE INSPECTION [12/2019 - ]

Result

Result: 

NG 

REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

Result: 

OK 

See step  13

1. Disconnect the M5 certification ECU (smart key ECU assembly) connector.
2. Disconnect the A42 stop light switch assembly connector.
3. Disconnect the A28 ECM connector.
4. Disconnect the A39 skid control ECU (brake actuator assembly) connector.
5. Disconnect the H28 shift lock control unit assembly connector.
6. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   M5-25 (STP1) - A42-3 (L)	Always	Below 1 Ω
   M5-25 (STP1) or A42-3 (L) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

for UA80E: Refer to INSPECTION [12/2019 - 10/2022]

for UA80F: Refer to INSPECTION [12/2019 - 10/2022]

Result

Result: 

NG 

REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY 

for UA80E: Refer to REMOVAL [12/2019 - 10/2022]

for UA80F: Refer to REMOVAL [12/2019 - 10/2022]

Result: 

OK 

See step  15

1. Disconnect the A19 certification ECU (smart key ECU assembly) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A19-9 (STAR) - C52-4 (B)	Always	Below 1 Ω
   A19-9 (STAR) or C52-4 (B) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Check that the steering unlocks when the ignition switch is turned to ACC.

   OK

   The steering unlocks.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

NG 

GO TO OTHER PROBLEM (Unable to Unlock Steering Wheel (Engine cannot Start)). Refer to  Unable to Unlock Steering Wheel (Engine cannot Start) [12/2019 - 10/2021] 

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A19-9 (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

   HINT: 

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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

OK 

See step  18

1. Disconnect the A19 certification ECU (smart key ECU assembly) connector.
2. Disconnect the C52 park/neutral position switch assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A19-9 (STAR) - C52-4 (B)	Always	Below 1 Ω
   A19-9 (STAR) or C52-4 (B) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  19

1. Install the ST relay to the No. 1 engine room relay block and No. 1 junction block assembly.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A19-20 (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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   HINT: 

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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2019 - 11/2023] 

Result: 

OK 

See step  20

1. Disconnect the A19 certification ECU (smart key ECU assembly) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A19-20 (STA) - 2 (ST relay)	Always	Below 1 Ω
   A19-20 (STA) or 2 (ST relay) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  21

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   C52-9 (L) - 2 (ST relay)	Always	Below 1 Ω
   C52-9 (L) or 2 (ST relay) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

GO TO SFI SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2022] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR