Toyota Avalon (XX50): Runnable Signal Malfunction (B2286,P0335). Engine Starter Communication Malfunction (B2779). Open / Short in Steering Lock ECU (B2781)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System(for Start Function, Gasoline Model) / Runnable Signal Malfunction (B2286,P0335). Engine Starter Communication Malfunction (B2779). Open / Short in Steering Lock ECU (B2781)

Runnable Signal Malfunction (B2286,P0335)

DESCRIPTION

These DTCs are stored when the engine speed signal sent by the ECM via direct line and the engine speed signal sent via CAN communication do not match.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B2286	Runnable Signal Malfunction	The engine speed signal sent by the ECM via direct line and the engine speed signal sent via CAN communication do not match. (1-trip detection logic*)	SFI system Certification ECU (smart key ECU assembly) Wire harness or connector	Disconnect the cable from the negative (-) battery terminal, wait 30 seconds and reconnect the cable to the negative (-) battery terminal. Wait 20 seconds or more with the engine switch off, then start the engine and maintain an engine speed of 1000 rpm or more for 20 seconds or more.
P0335	Crankshaft Position Sensor Circuit Malfunction (NE Signal)	The engine speed signal sent by the ECM via direct line and the engine speed signal sent via CAN communication do not match. (1-trip detection logic*)	SFI system Certification ECU (smart key ECU assembly) Wire harness or connector	Allow the engine to idle for 10 seconds or more.

*: Only detected while a malfunction is present and the engine switch is on (IG).

Vehicle Condition and Fail-safe Function when Malfunction Detected

Vehicle Condition when Malfunction Detected	Fail-safe Function when Malfunction Detected
When a malfunction occurs and the vehicle speed signal sent via either direct line or CAN communication indicates no vehicle speed, there is no effect on vehicle behavior. (A malfunction is detected after the engine switch is turned on (IG).) When a malfunction occurs and the vehicle speed signal sent via either direct line or CAN communication indicates that the vehicle is moving, the engine cannot be started. However, the engine can be started after the engine switch has been turned off.	When a malfunction occurs and the vehicle speed signal sent via either direct line or CAN communication indicates no vehicle speed, there is no effect on vehicle behavior. When the signal sent via either direct line or CAN communication is malfunctioning and indicates that the vehicle is moving: If the following conditions are met, it can be determined that the malfunction is not in the CAN communication system but in the direct line (NE). When the engine switch is pressed, the system controls the engine based on the starter OFF permission flag (perfect injection signal judgment) via CAN communication, causing the engine to stop cranking. When the engine switch is pressed and held, the system controls the engine based on the engine speed signal via CAN communication, causing the engine to stop cranking. If the following conditions are met, it can be determined that the malfunction is not in the direct line (NE) but in the CAN communication system. When the engine switch is pressed, the system controls the engine based on the engine speed signal via direct line, causing the engine to stop cranking. When the engine switch is pressed and held, the system controls the engine based on the engine speed signal via direct line, causing the engine to stop cranking. If the following conditions are met, it can be determined that there is a malfunction in both the CAN communication system and the direct line (NE). When the engine switch is pressed, the engine stops cranking after 6 seconds. When the engine switch is pressed and held, the engine cranks for up to 30 seconds.

Vehicle Condition when Malfunction Detected

Fail-safe Function when Malfunction Detected

When a malfunction occurs and the vehicle speed signal sent via either direct line or CAN communication indicates no vehicle speed, there is no effect on vehicle behavior. (A malfunction is detected after the engine switch is turned on (IG).)
When a malfunction occurs and the vehicle speed signal sent via either direct line or CAN communication indicates that the vehicle is moving, the engine cannot be started. However, the engine can be started after the engine switch has been turned off.

When a malfunction occurs and the vehicle speed signal sent via either direct line or CAN communication indicates no vehicle speed, there is no effect on vehicle behavior.
When the signal sent via either direct line or CAN communication is malfunctioning and indicates that the vehicle is moving:
If the following conditions are met, it can be determined that the malfunction is not in the CAN communication system but in the direct line (NE).
- When the engine switch is pressed, the system controls the engine based on the starter OFF permission flag (perfect injection signal judgment) via CAN communication, causing the engine to stop cranking.
- When the engine switch is pressed and held, the system controls the engine based on the engine speed signal via CAN communication, causing the engine to stop cranking.
If the following conditions are met, it can be determined that the malfunction is not in the direct line (NE) but in the CAN communication system.
- When the engine switch is pressed, the system controls the engine based on the engine speed signal via direct line, causing the engine to stop cranking.
- When the engine switch is pressed and held, the system controls the engine based on the engine speed signal via direct line, causing the engine to stop cranking.
If the following conditions are met, it can be determined that there is a malfunction in both the CAN communication system and the direct line (NE).
- When the engine switch is pressed, the engine stops cranking after 6 seconds.
- When the engine switch is pressed and held, the engine cranks for up to 30 seconds.

Related Data List and Active Test Items

DTC No.	Data List and Active Test
B2286 P0335	Power Source Control Engine Condition Starting Control Engine Speed

DTC No.

Data List and Active Test

B2286

P0335

Power Source Control

Engine Condition

Starting Control

Engine Speed

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
Inspect the fuses of circuits related to this system before performing the following procedure.
Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
Click here
After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

HINT:

When the cable is disconnected and reconnected to the negative (-) battery terminal, the power source mode returns to the state it was in before the cable was disconnected.

PROCEDURE

1.	READ VALUE USING TECHSTREAM (ENGINE CONDITION / ENGINE SPEED)

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Body Electrical / Power Source Control or Starting 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
Engine Condition	Engine state	Stop or Run	Stop: Engine stopped Run: Engine running	-

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Engine Condition

Engine state

Stop or Run

Stop: Engine stopped

Run: Engine running

Body Electrical > Power Source Control > Data List

Tester Display
Engine Condition

Body Electrical > Starting Control > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Engine Speed	Engine speed	0 to 16383 rpm	Fluctuates in accordance with actual engine speed	-

Body Electrical > Starting Control > Data List

Tester Display
Engine Speed

OK:

The Techstream display changes correctly in response to the engine condition.

REPLACE ECM

2.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ECM)

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

(b) Disconnect the A18 ECM connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A10-16 (NE) - A18-30 (NEO)	Always	Below 1 Ω
A10-16 (NE) or A18-30 (NEO) - Other terminals and body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

(b) Connect the A18 ECM connector.

(c) Using an oscilloscope, check the engine speed input signal waveform at the terminal of the certification ECU (smart key ECU assembly).

OK:

Tester Connection	Condition	Specified Condition
A10-16 (NE) - Body ground	Engine stopped	No pulse generation
A10-16 (NE) - Body ground	Engine running	Pulse generation

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

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

REPLACE ECM

Engine Starter Communication Malfunction (B2779)

DESCRIPTION

If the remote engine start ECU does not respond to the certification ECU (smart key ECU assembly) or the remote engine start ID is not registered, this DTC is stored.

HINT:

Registration status of the remote engine start ECU ID can be checked using the "Wireless C Code" item in the Data List.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B2779	Engine Starter Communication Malfunction	One of the following conditions is met (1 trip detection logic*): A remote start communication error occurs. Response is not possible. Registration has not been performed.	CAN communication system Remote engine start ECU Certification ECU (smart key ECU assembly)	DTC output confirmation operation: A remote start operation is performed.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B2779

Engine Starter Communication Malfunction

One of the following conditions is met (1 trip detection logic*):

A remote start communication error occurs.
Response is not possible.
Registration has not been performed.

CAN communication system
Remote engine start ECU
Certification ECU (smart key ECU assembly)

DTC output confirmation operation:

A remote start operation is performed.

*: Only output while a malfunction is present.

Vehicle Condition and Fail-safe Operation when Malfunction Detected

Vehicle Condition when Malfunction Detected	Fail-safe Operation when Malfunction Detected
Engine does not start with remote start operation	Engine cannot be started by remote start operation only

Related Data List and Active Test

DTC No.	Data List and Active Test
B2779	Smart Key Wireless Starter Com ID Wireless C Code

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.
Before performing the inspection, check that DTC B1242 (wireless door lock control system) is not output.
Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
Click here
After performing repairs, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".

PROCEDURE

1.	CHECK CAN COMMUNICATION SYSTEM

(a) Check for CAN communication system DTCs.

Click here

OK:

CAN communication DTCs are not output.

GO TO CAN COMMUNICATION SYSTEM (DIAGNOSTIC TROUBLE CODE CHART)

2.	READ VALUE USING TECHSTREAM (WIRELESS C CODE)

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Body Electrical / Smart Key / Data List.

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

Body Electrical > Smart Key > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Wireless C Code	Registration status between remote engine start ECU and certification ECU (smart key ECU assembly)	No Regd or Regd	No Regd: Remote starter ID not registered to remote engine start ECU and certification ECU (smart key ECU assembly) Regd: Remote starter ID registered to remote engine start ECU and certification ECU (smart key ECU assembly)	Problems may be caused by the following: DTC B2779 is stored. Remote engine start ECU registration has not been performed. Malfunctions in the certification ECU (smart key ECU assembly) or remote engine start ECU.

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Wireless C Code

Registration status between remote engine start ECU and certification ECU (smart key ECU assembly)

No Regd or Regd

No Regd: Remote starter ID not registered to remote engine start ECU and certification ECU (smart key ECU assembly)

Regd: Remote starter ID registered to remote engine start ECU and certification ECU (smart key ECU assembly)

Problems may be caused by the following:

DTC B2779 is stored.
Remote engine start ECU registration has not been performed.
Malfunctions in the certification ECU (smart key ECU assembly) or remote engine start ECU.

Body Electrical > Smart Key > Data List

Tester Display
Wireless C Code

Result	Proceed to
"No Regd" is displayed on the Techstream	A
"Regd" is displayed on the Techstream	B

REPLACE REMOTE ENGINE START ECU

3.	REGISTER REMOTE ENGINE STARTER ID

(a) Register the remote engine starter ID.

4.	READ VALUE USING TECHSTREAM (WIRELESS C CODE)

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Body Electrical / Smart Key / Data List.

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

Body Electrical > Smart Key > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Wireless C Code	Registration status between remote engine start ECU and certification ECU (smart key ECU assembly)	No Regd or Regd	No Regd: Remote starter ID not registered to remote engine start ECU and certification ECU (smart key ECU assembly) Regd: Remote starter ID registered to remote engine start ECU and certification ECU (smart key ECU assembly)	Problems may be caused by the following: DTC B2779 is stored. Remote engine start ECU registration has not been performed. Malfunctions in the certification ECU (smart key ECU assembly) or remote engine start ECU.

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Wireless C Code

Registration status between remote engine start ECU and certification ECU (smart key ECU assembly)

No Regd or Regd

No Regd: Remote starter ID not registered to remote engine start ECU and certification ECU (smart key ECU assembly)

Regd: Remote starter ID registered to remote engine start ECU and certification ECU (smart key ECU assembly)

Problems may be caused by the following:

DTC B2779 is stored.
Remote engine start ECU registration has not been performed.
Malfunctions in the certification ECU (smart key ECU assembly) or remote engine start ECU.

Body Electrical > Smart Key > Data List

Tester Display
Wireless C Code

Result	Proceed to
"No Regd" is displayed on the Techstream	A
"Regd" is displayed on the Techstream	B

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

REPLACE REMOTE ENGINE START ECU

Open / Short in Steering Lock ECU (B2781)

DESCRIPTION

The steering lock ECU and steering lock motor are built into the steering lock actuator or upper bracket assembly.

The steering lock ECU (steering lock actuator or upper bracket assembly) detects whether the steering lock is in the lock or unlock position by using the lock sensor and unlock sensor of the steering lock motor.

The steering lock ECU (steering lock actuator or upper bracket assembly) receives lock and unlock request signals from the certification ECU (smart key ECU assembly) and responds with lock and unlock operation signals.

HINT:

The steering lock ECU (steering lock actuator or upper bracket assembly) is not connected to the CAN communication system. However, the steering lock ECU (steering lock actuator or upper bracket assembly) is connected to the certification ECU (smart key ECU assembly) via LIN communication and communicates with other components via CAN communication through the certification ECU (smart key ECU assembly).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Note
B2781	Open / Short in Steering Lock ECU	One of the following conditions is met (1-trip detection logic (Only output while a malfunction is present and the engine switch is on (IG).)): The steering lock sensor or unlock sensor is malfunctioning (When both detection switches turn on, the system is determined to be malfunctioning). The steering lock motor activation circuit has a short circuit. The steering lock motor activation circuit has an open circuit.	Steering lock ECU (steering lock actuator or upper bracket assembly) LIN communication system	DTC Output Confirmation Operation: No confirmation operation is necessary (monitoring is continuous).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B2781

Open / Short in Steering Lock ECU

One of the following conditions is met (1-trip detection logic (Only output while a malfunction is present and the engine switch is on (IG).)):

The steering lock sensor or unlock sensor is malfunctioning (When both detection switches turn on, the system is determined to be malfunctioning).
The steering lock motor activation circuit has a short circuit.
The steering lock motor activation circuit has an open circuit.

Steering lock ECU (steering lock actuator or upper bracket assembly)
LIN communication system

DTC Output Confirmation Operation: No confirmation operation is necessary (monitoring is continuous).

Vehicle Condition and Fail-safe Function when Malfunction Detected

Vehicle Condition when Malfunction Detected	Fail-safe Function when Malfunction Detected
The steering cannot be locked or unlocked. For this reason, the engine cannot be started.	Prohibits the engine from being started (the engine does not crank).

Related Data List and Active Test Items

DTC No.	Data List and Active Test
B2781	Smart Key Sensor Value Motor Driver Short

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the engine switch off, connect the Techstream to the vehicle 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 Model Code "KEY REGIST" 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
Before replacing the steering lock ECU (steering lock actuator or upper bracket assembly), refer to Registration.
Click here
After performing repairs, confirm that no DTCs are output again.
Click here

HINT:

When all the ECUs that are connected via LIN communication cannot communicate with the certification ECU (smart key ECU assembly), DTC B2785 is stored.

PROCEDURE

CHECK DTC

(a) Using the Techstream, check if LIN communication DTC B2785 is output.

Body Electrical > Smart Key > Trouble Codes

HINT:

If a LIN communication DTC is output, perform troubleshooting for the LIN communication system.

Click here

Result	Proceed to
DTC B2785 is output.	A
DTC B2785 is not output.	B

GO TO LIN COMMUNICATION SYSTEM (DTC B2785)

REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)

Vehicle Speed Signal Malfunction (B2282,B2283). Brake Signal Malfunction (B2284). Steering Lock Position Signal Circuit Malfunction (B2285)

Power Source Control ECU Malfunction (B2782). Antenna Coil Open / Short (B2784). IG2 Signal Malfunction (B2788)

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