DESCRIPTION
When there is a short to GND in the power supply for the transponder key amplifier of the engine switch, the certification ECU (smart key ECU assembly) stores this DTC.
DTC No. |
Detection Item |
DTC Detection Condition |
Trouble Area |
Note |
---|---|---|---|---|
B278A |
Short to GND in Immobiliser System Power Source Circuit |
A short to GND in the power supply of the transponder key amplifier of the engine switch (VC5 - VC5) detected. (1 trip detection logic*1) |
|
DTC output confirmation operation:
|
Vehicle Condition when Malfunction Detected |
Fail-safe Operation when Malfunction Detected |
---|---|
Engine cannot be started when transmitter battery is depleted by holding transmitter near engine switch and pressing and holding engine switch with shift lever in P |
- |
DTC No. |
Data List and Active Test |
---|---|
B278A |
- |
WIRING DIAGRAM
Refer to B2784.
Click here
CAUTION / NOTICE / HINT
NOTICE:
Click here
PROCEDURE
1. |
CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
(a) Using an oscilloscope, check the waveform.
*a |
Component with harness connected (Engine Switch) |
- |
- |
HINT:
Perform this inspection on the engine switch side.
Measurement Condition:
Tester Connection |
Condition |
Tool Setting |
Specified Condition |
---|---|---|---|
F59-10 (VC5) - F59-6 (AGND) |
Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds of engine switch pressed |
2 V/DIV., 200 ms./DIV. |
Pulse generation |
OK:
The waveform is similar to that shown in the illustration.
OK |
REPLACE ENGINE SWITCH |
|
2. |
CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ENGINE SWITCH) |
(a) Disconnect the F1 certification ECU (smart key ECU assembly) connector.
(b) Disconnect the F59 engine switch connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
F1-7 (VC5) - F59-10 (VC5) |
Always |
Below 1 Ω |
F1-11 (AGND) - F59-6 (AGND) |
Always |
Below 1 Ω |
F1-7 (VC5) or F59-10 (VC5) - Body ground |
Always |
10 kΩ or higher |
F1-11 (AGND) or F59-6 (AGND) - Body ground |
Always |
10 kΩ or higher |
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
3. |
CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
(a) Reconnect the F1 certification ECU (smart key ECU assembly) connector.
(b) Reconnect the F59 engine switch connector.
(c) Measure the voltage according to the value(s) in the table below.
*a |
Component with harness connected (Certification ECU (Smart Key ECU Assembly)) |
- |
- |
Standard Voltage:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
F1-7 (VC5) - F1-11 (AGND) |
Engine switch off, brake pedal not depressed, 30 seconds or more after driver door opened and then closed |
Below 1 V |
OK |
REPLACE ENGINE SWITCH |
NG |
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
Toyota CH-R Service Manual > Vacuum Pump: Components
COMPONENTS
ILLUSTRATION
*1
ENGINE WIRE
*2
NO. 2 CYLINDER HEAD COVER
N*m (kgf*cm, ft.*lbf): Specified torque
-
-
ILLUSTRATION
*1
UNION TO CONNECTOR TUBE HOSE
* ...
Toyota CH-R Service Manual > Power Steering System: TC and CG Terminal Circuit
DESCRIPTION
Connecting terminals TC and CG of the DLC3 causes the ECU to display DTCs by
blinking the EPS warning light.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
If the power steering ECU assembly has been replaced, perform assist map writing
and torque sensor zero point calibration ...