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 |
Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
(P0128)
DESCRIPTION
HINT:
This DTC relates to the thermostat.
This DTC is stored when the engine coolant temperature does not reach 75°C (167°F)
despite sufficient engine warm-up time having elapsed.
DTC No.
DTC Detection Condition
...
Definition Of Terms
DEFINITION OF TERMS
Term
Definition
Monitor Description
Description of what the ECM monitors and how it detects malfunctions
(monitoring purpose and details).
Related DTCs
Group ...
Installation
INSTALLATION
CAUTION / NOTICE / HINT
HINT:
Use the same procedure for the RH side and LH side.
The procedure listed below is for the LH side.
PROCEDURE
1. SECURE REAR SHOCK ABSORBER WITH COIL SPRING
2. INSTALL REAR LOWER COIL SPRING ...