Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001ARG2
Model Year Start: 2019 Model: Avalon Prod Date Range: [04/2018 - 08/2020]
Title: THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): Engine does not Start; 2019 - 2020 MY Avalon [04/2018 - 08/2020]

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

Smart Key

  • Immobiliser
  • Engine Start Request
  • L Code Check

Starting Control

  • Starter SW
  • Shift Position P or N
  • Ignition

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

    Click here 2019 - 2022 MY Avalon [04/2018 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING

  • If the smart key system (for Start Function, Gasoline Model) has been disabled, enable the system before performing troubleshooting.

    Click here 2019 - 2022 MY Avalon [04/2018 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): CUSTOMIZE PARAMETERS

  • Inspect the fuses of 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 Registration.

    Click here 2019 - 2020 MY Avalon [04/2018 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION

  • 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."

HINT:

  • 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

1.

CHECK ENGINE CRANKING OPERATION

(a) Get into the vehicle while carrying an electrical key transmitter sub-assembly.

(b) Move the shift lever to P.

(c) 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

Proceed to

Engine cranks and initial combustion occurs

A

Engine cranks but initial combustion does not occur

B

Engine does not crank

C
A

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

B

GO TO SFI SYSTEM

C

2.

CHECK ENGINE SWITCH CONDITION

(a) Get into the vehicle while carrying an electrical key transmitter sub-assembly.

(b) Move the shift lever to P.

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

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
B

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

C

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

D

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

A

3.

READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH1)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

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

(e) Read the Data List according to the display on the Techstream.

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 Techstream display changes correctly in response to the brake pedal operation.

NG

GO TO STEP 12

OK

4.

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

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

(b) Read the Data List according to the display on the Techstream.

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 Techstream display changes correctly in response to the shift lever operation.

NG

GO TO STEP 15

OK

5.

READ VALUE USING TECHSTREAM (STARTER REQUEST SIGNAL)

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

(b) Read the Data List according to the display on the Techstream.

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

NOTICE:

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 Techstream display changes correctly in response to the engine switch operation.

NG

GO TO STEP 17

OK

6.

READ VALUE USING TECHSTREAM (STARTER REQUEST SIGNAL)

(a) Get into the vehicle while carrying an electrical key transmitter sub-assembly.

(b) Move the shift lever to P.

(c) Enter the following menus: Body Electrical / Starting Control / Data List.

(d) According to the display on the Techstream, 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 Techstream display changes.

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

OK

7.

INSPECT ST RELAY

(a) Inspect the ST relay.

Click here 2019 - 2022 MY Avalon [04/2018 -        ]; 2GR-FKS (STARTING): RELAY: INSPECTION

NG

REPLACE ST RELAY
OK

8.

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

(a) 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

HINT:

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

*1

NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY

(ST Relay Holder)
NG

GO TO STEP 18

OK

9.

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

(a) 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

*1

NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY

(ST Relay Holder)

(b) 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
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

10.

CHECK HARNESS AND CONNECTOR (STARTER ASSEMBLY - ST RELAY)

(a) Disconnect the C58 starter assembly connector.

(b) 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 - C58-1

Always

Below 1 Ω

No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 3 or C58-1 - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

11.

CHECK HARNESS AND CONNECTOR (STARTER ASSEMBLY - BATTERY)

(a) Disconnect the C70 starter assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

C70-1 - Body ground

Always

11 to 14 V
OK

REPLACE STARTER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - POWER SOURCE AND BODY GROUND)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A33-7 (B) - Body ground

Always

11 to 14 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

A33-2 (GND) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

13.

INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Inspect the stop light switch assembly.

Click here 2019 - 2022 MY Avalon Avalon HV [04/2018 -        ]; LIGHTING (EXT): STOP LIGHT SWITCH: ON-VEHICLE INSPECTION

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

14.

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

(a) Disconnect the A33 stop light switch assembly connector.

(b) Disconnect the K10 certification ECU (smart key ECU assembly) connector.

(c) Disconnect the A18 ECM connector.

(d) Disconnect the A28 skid control ECU (brake actuator assembly) connector.

(e) Disconnect the G21 shift lock control unit assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K10-25 (STP1) - A33-3 (L)

Always

Below 1 Ω

K10-25 (STP1) or A33-3 (L) - Other terminals and body ground

Always

10 kΩ or higher
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

15.

INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY

(a) Remove the park/neutral position switch assembly.

Click here 2019 - 2021 MY Avalon [04/2018 - 08/2021]; UA80E (AUTOMATIC TRANSMISSION / TRANSAXLE): PARK / NEUTRAL POSITION SWITCH: REMOVAL

(b) Inspect the park/neutral position switch assembly.

Click here 2019 - 2022 MY Avalon [04/2018 -        ]; UA80E (AUTOMATIC TRANSMISSION / TRANSAXLE): PARK / NEUTRAL POSITION SWITCH: INSPECTION

NG

REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY

OK

16.

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

(a) Disconnect the A10 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A10-9 (STAR) - C53-4 (B)

Always

Below 1 Ω

A10-9 (STAR) or C53-4 (B) - Other terminals and body ground

Always

10 kΩ or higher
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

17.

CHECK STEERING LOCK FUNCTION

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

OK:

The steering unlocks.

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

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

18.

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A10-9 (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 battery voltage may drop to approximately 6 V.

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

OK

19.

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

(a) Disconnect the A10 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the C53 park/neutral position switch assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A10-9 (STAR) - C53-4 (B)

Always

Below 1 Ω

A10-9 (STAR) or C53-4 (B) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

20.

CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Install the ST relay to the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A10-20 (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

HINT:

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

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

OK

21.

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

(a) Disconnect the A10 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A10-20 (STA) - No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 2

Always

Below 1 Ω

A10-20 (STA) or No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 2 - Other terminals and body ground

Always

10 kΩ or higher

*1

NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY

(ST Relay Holder)
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

22.

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C53-9 (L) - No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 2

Always

Below 1 Ω

C53-9 (L) or No. 1 engine room relay block and No. 1 junction block assembly ST relay terminal 2 - Other terminals and body ground

Always

10 kΩ or higher

*1

NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY

(ST Relay Holder)
OK

GO TO SFI SYSTEM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR