THEFT DETERRENT / KEYLESS ENTRY IMMOBILISER SYSTEM(w/ Smart Entry and Start System) B278A Short to GND in Immobiliser System Power Source Circuit
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) (1 trip detection logic*1). | ·
Engine switch ·
Wire harness or connector ·
Certification ECU (smart key ECU assembly) |
DTC output confirmation operation:
With the shift lever in P*2 and the electrical key transmitter sub-assembly held near the engine switch, an engine start operation is performed by pressing and holding the engine switch when the transmitter battery is depleted. |
*1: Only output while a malfunction is present.
*2: except Manual Transaxle
| Vehicle Condition when Malfunction Detected | Fail-safe Operation when Malfunction Detected |
|---|---|
| Engine cannot be started when key battery is depleted by holding electrical key transmitter sub-assembly near engine switch and pressing and holding engine switch with shift lever in P*. | - |
*: except Manual Transaxle
| DTC No. | Data List and Active Test |
|---|---|
| B278A | - |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
- NOTICE:
- ·
When using the GTS with the engine switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select Model Code "KEY REGIST" under manual mode and enter the following menus: Body Electrical / Entry&Start(CAN). While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.
·Before replacing the certification ECU (smart key ECU assembly), refer to Service Bulletin.
·After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".
PROCEDURE
Using an oscilloscope, check the waveform.
| *a | Component with harness connected
(Engine Switch) |
*b | See waveform |
- HINT:
-
Perform this inspection on the engine switch side.
| Tester Connection | Condition | Tool Setting | Specified Condition |
|---|---|---|---|
| E111-10 (VC5) - E111-6 (AGND) | Engine switch off, electrical key transmitter sub-assembly not in cabin, within 30 seconds after engine switch pressed | 2 V/DIV., 200 ms./DIV. | Pulse generation
(See waveform) |
- OK:
The waveform is similar to that shown in the illustration.
- Result:
Proceed to OK NG
OK
NG
Disconnect the E110 certification ECU (smart key ECU assembly) connector.
Disconnect the E111 engine switch connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition E110-1 (VC5) - E111-10 (VC5) Always Below 1 Ω E110-24 (AGND) - E111-6 (AGND) Always Below 1 Ω E111-10 (VC5) - Body ground Always 10 kΩ or higher E110-1 (VC5) - Body ground Always 10 kΩ or higher E111-6 (AGND) - Body ground Always 10 kΩ or higher E110-24 (AGND) - Body ground Always 10 kΩ or higher
- Result:
Proceed to OK NG
OK
NG