Toyota Tacoma (2015-2018) Service Manual: Communication Malfunction between ECUs Connected by LIN (B2785)
DESCRIPTION
The certification ECU (smart key ECU assembly) monitors communication between all the ECUs connected to the certification bus lines. When the certification ECU (smart key ECU assembly) detects errors in communication with all the ECUs connected to the certification bus lines at a set interval and 3 times in a row, DTC B2785 will be stored.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
B2785 |
|
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- If the certification ECU (smart key ECU assembly) is replaced, register
the keys (See page
.gif)
). - If the steering lock ECU (steering lock actuator or upper bracket assembly)
is replaced, register the ECU code (See page
).
- When using the Techstream with the vehicle ignition 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 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.
PROCEDURE
|
1. |
CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)) |
(a) Disconnect the C29 certification ECU (smart key ECU assembly) connector.
(b) Disconnect the S45 steering lock ECU (steering lock actuator or upper bracket assembly) connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
C29-6 (LIN) - S45-5 (LIN) |
Always |
Below 1 Ω |
|
C29-6 (LIN) or S45-5 (LIN) - Body ground |
Always |
10 kΩ or higher |
| NG | .gif) |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
.gif)
|
2. |
CHECK DTC OUTPUT (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)) |
(a) Reconnect the C29 certification ECU (smart key ECU assembly) connector.
(b) Clear the DTCs (See page ).
(c) Recheck for DTCs.
|
Result |
Proceed to |
|---|---|
|
DTC B2785 is output |
A |
|
DTC B2785 is not output |
B |
| A | |
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
| B | |
REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) |
Dtc Check / Clear
DTC CHECK / CLEAR
1. CHECK DTC
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Smart Acces ...
No Response from Steering Lock ECU (B2786)
DESCRIPTION
This DTC is stored when LIN communication between the certification ECU (smart
key ECU assembly) and steering lock ECU (steering lock actuator or upper bracket
assembly) stops for 10 ...
Other materials:
Theft Deterrent System Communication Line High Fixation (B279A,B279A12)
DESCRIPTION
If the communication line (EFIO-IMI) to the transponder key ECU assembly is stuck
high (e.g. shorted to +B), the ECM stores this DTC.
DTC No.
DTC Detection Condition
Trouble Area
DTC Output Confirmation Operation
B279A*1
...
Torque Converter Clutch Pressure Control Solenoid Control Circuit Electrical
(Shift Solenoid Valve SLU) (P2759)
DESCRIPTION
Refer to the system description for DTC P2757 (See page
).
DTC No.
DTC Detection Condition
Trouble Area
P2759
Open or short is detected in shift solenoid valve SLU circuit for 1 second
or more while driving (1 trip dete ...
ECM Communication Circuit Malfunction (C1203)
DESCRIPTION
The circuit is used to send TRAC and VSC control information from the skid control
ECU (brake actuator assembly) to the ECM, and engine control information from the
ECM to the skid control ECU (brake actuator assembly) through the CAN communication
system.
for 4WD or w/ Rear Diff ...
