Lexus NX manuals

Lexus NX: Engine Starter Communication Malfunction (B2779)

Lexus NX Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Immobiliser System / 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.

If communication between the remote engine start ECU and the certification ECU (smart key ECU assembly) is established and the remote engine start is operated, this DTC and the corresponding history DTC will be cleared.

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.
  • Remote engine start ECU
  • Main body ECU (multiplex network body 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

Hybrid control system does not start with remote start operation

Hybrid control system cannot be started by remote start operation only
Related Data List and Active Test

DTC No.

Data List and Active Test

B2779
  • Wireless Starter Com ID
  • Wireless C Code

CAUTION / NOTICE / HINT

NOTICE:

  • When using the Techstream with the power 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 Access. 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 U0142 is not output.
  • Before replacing the certification ECU (smart key ECU assembly) or main body ECU (multiplex network body ECU), refer to Registration.

    Click here

  • After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation."

PROCEDURE

1.

READ VALUE USING TECHSTREAM (WIRELESS C CODE)

(a) Turn the power switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the power switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / Smart Access / Data List.

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

Body Electrical > Smart Access > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Wireless C Code

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

No Regd or Regd

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

Regd: ID registered between 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 Access > 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
B

GO TO STEP 4

A

2.

REGISTER REMOTE ENGINE STARTER ID

(a) Register the remote engine starter ID.

Click here

NEXT

3.

CHECK REMOTE ENGINE STARTER FUNCTION

(a) Check the remote engine starter function.

OK:

Remote engine starter functions operate normally.

OK

END (REMOTE ENGINE STARTER ID REGISTRATION WAS DEFECTIVE)
NG

GO TO STEP 4

4.

REPLACE REMOTE ENGINE STARTER ECU

(a) Replace the remote engine starter ECU with a new one.

(b) Register the remote engine starter ID.

Click here

(c) Check the remote engine starter function.

OK:

Remote engine starter functions operate normally.

OK

END (REMOTE ENGINE STARTER ECU WAS DEFECTIVE)
NG

5.

CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

(a) Replace the main body ECU (multiplex network body ECU) with a new one.

Click here

HINT:

Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

Click here

(b) Check the remote engine starter function.

OK:

Remote engine starter functions operate normally.

OK

END (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) WAS DEFECTIVE)
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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