DESCRIPTION
This DTC is stored when the engine switch power source supply line is open or shorted.
DTC No. |
DTC Detection Condition |
Trouble Area |
---|---|---|
B278A |
Engine switch power source supply line is open or shorted. |
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
If the certification ECU (smart key ECU assembly) is replaced, register the key (See page ).
PROCEDURE
1. |
CHECK DTC OUTPUT |
(a) Clear the DTCs (See page ).
(b) Recheck for DTCs (See page ).
OK:
DTC B278A is not output.
OK |
USE SIMULATION METHOD TO CHECK |
|
2. |
CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ENGINE SWITCH) |
(a) Disconnect the certification ECU (smart key ECU assembly) connector.
(b) Disconnect the engine switch connector. |
|
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
D25-28 (VC5) - D13-14 (VC5) |
Always |
Below 1 Ω |
D25-36 (AGND) - D13-8 (AGND) |
Always |
Below 1 Ω |
D25-28 (VC5) - Body ground |
Always |
10 kΩ or higher |
D25-36 (AGND) - Body ground |
Always |
10 kΩ or higher |
*1 |
Front view of wire harness connector (to Certification ECU (Smart Key ECU Assembly)) |
*2 |
Front view of wire harness connector (to Engine Switch) |
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
3. |
CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
(a) Reconnect the certification ECU (smart key ECU assembly) connector.
(b) Reconnect the engine switch connector.
(c) Using an oscilloscope, check the waveform.
Waveform (Reference):
Item |
Content |
---|---|
Tester Connection |
D25-28 (VC5) - D25-36 (AGND) |
Tool Setting |
2 V/DIV., 200 ms./DIV. |
Condition |
|
OK:
Waveform is output normally (see illustration)
Result |
Proceed to |
---|---|
NG |
A |
OK (for 2GR-FE) |
B |
OK (for 1AR-FE) |
C |
*1 |
Component with harness connected (Certification ECU (Smart Key ECU Assembly)) |
*2 |
GND |
A |
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
B |
REPLACE ENGINE SWITCH |
C |
REPLACE ENGINE SWITCH |
Data Signal Circuit between Navigation Receiver Assembly and Extension Module
DESCRIPTION
The stereo component tuner assembly sends the image data signal to the navigation
receiver assembly via this circuit.
WIRING DIAGRAM
PROCEDURE
1.
CHECK NAVIGATION WIRE
(a) Remove the navigation wire (See pag ...
Data List / Active Test
DATA LIST / ACTIVE TEST
1. DATA LIST
HINT:
Using the Techstream to read the Data List allows the values or states of switches,
sensors, actuators and other items to be read without removing any parts. This non-intrusive
inspection can be very useful bec ...
Sound Signal Circuit between Radio Receiver and Stereo Jack Adapter
DESCRIPTION
The No. 1 stereo jack adapter assembly sends the sound signal from an
external device to the radio and display receiver assembly via this circuit.
The sound signal that has been sent is amplified by the radio and display
receiver ...