Toyota Avalon (XX50): Engine Immobiliser System Circuit Short to Battery (B279A12). Engine Immobiliser System Incorrect Assembly (B279C95). Ignition Hold Monitor Malfunction (B2271)
Engine Immobiliser System Circuit Short to Battery (B279A12)
DESCRIPTION
If the
communication line (IMI - EFIO) between the hybrid vehicle control ECU
and certification ECU (smart key ECU assembly) is stuck high, the hybrid
vehicle control ECU will store this DTC.
|
DTC No. | Detection Item |
DTC Detection Condition | Trouble Area |
Note |
| B279A12 |
Engine Immobiliser System Circuit Short to Battery |
The
communication line (IMI - EFIO) between the hybrid vehicle control ECU
and certification ECU (smart key ECU assembly) is stuck high. (1 trip
detection logic*) |
- Certification ECU (smart key ECU assembly)
- Hybrid vehicle control ECU
- Wire harness or connector
| DTC output confirmation operation:
- Turn the power switch on (IG) and wait 6 seconds.
|
- *: Only output while a malfunction is present.
Vehicle Condition and Fail-safe Operation when Malfunction Detected |
Vehicle Condition when Malfunction Detected |
Fail-safe Operation when Malfunction Detected |
|
Hybrid control system cannot be started |
Hybrid control system cannot be started |
Related Data List and Active Test |
DTC No. | Data List and Active Test |
|
B279A12 | - |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- When using the Techstream with the power switch off, connect the
Techstream to the DLC3 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 Key.
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.
- The smart key system (for Start Function, HV Model) uses the LIN
communication system and CAN communication system. Inspect the
communication function by following How to Proceed with Troubleshooting.
Troubleshoot the smart key system (for Start Function, HV Model) after
confirming that the communication systems are functioning properly.
Click here 
- Before replacing the hybrid vehicle control ECU or certification ECU (smart key ECU assembly), refer to Registration.
Click here
- After performing repairs, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".
HINT:
When DTC
B279A12 and the certification ECU (smart key ECU assembly) DTC are
output simultaneously, first perform troubleshooting for the
certification ECU (smart key ECU assembly) DTC.
PROCEDURE
| 1. |
CHECK CONNECTION OF CONNECTOR |
(a) Turn the power switch off.
(b)
Check that the connectors are properly connected to the hybrid vehicle
control ECU and certification ECU (smart key ECU assembly).
OK:
Connectors are properly connected.
| NG |
 | CONNECT CONNECTORS PROPERLY |
|
OK |
 | |
| 2. |
CHECK WHETHER HYBRID CONTROL SYSTEM STARTS |
(a) Check that the hybrid control system starts.
OK:
Hybrid control system starts normally.
| OK |
| USE SIMULATION METHOD TO CHECK |
|
NG | |
| |
| 3. |
CHECK HYBRID VEHICLE CONTROL ECU |
(a) Disconnect the A10 certification ECU (smart key ECU assembly) connector.
| (b) Measure the voltage according to the value(s) in the table below.
Standard Voltage: |
Tester Connection | Condition |
Specified Condition | |
A10-4 (EFIO) - Body ground |
Power switch off |
11 to 14 V → 1 V or less | |
 |
|
*a | Front view of wire harness connector
(to Certification ECU (Smart Key ECU Assembly)) | | |
| NG |
| GO TO STEP 5 |
|
OK | |
| |
| 4. |
CHECK HYBRID VEHICLE CONTROL ECU (TERMINAL IMI) |
(a) Connect the A10 certification ECU (smart key ECU assembly) connector.
(b) Using an oscilloscope, check the waveform.
|
*a | Component with harness connected
(Hybrid Vehicle Control ECU) |
*b | Waveform |
|
*c | Approximately 160 ms. |
*d | Approximately 270 ms. |
OK:
|
Tester Connection | Condition |
Tool Setting | Specified Condition |
|
G47-22 (IMI) - Body ground |
Within
3 seconds of hybrid control system start or within 3 seconds of power
switch turned on (IG) after cable disconnected and reconnected to
auxiliary battery | 2 V/DIV., 500 ms./DIV. |
Pulse generation (See waveform) |
| OK |
| REPLACE HYBRID VEHICLE CONTROL ECU |
| NG |
| REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
| 5. |
CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - HYBRID VEHICLE CONTROL ECU) |
(a) Disconnect the G47 hybrid vehicle control ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|
A10-4 (EFIO) - G47-22 (IMI) |
Always | Below 1 Ω |
| OK |
| REPLACE HYBRID VEHICLE CONTROL ECU |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
Engine Immobiliser System Incorrect Assembly (B279C95)
DESCRIPTION
If a hybrid
vehicle control ECU that is incompatible with the immobiliser function
is installed, the hybrid vehicle control ECU will store this DTC.
|
DTC No. | Detection Item |
DTC Detection Condition | Trouble Area |
Note |
| B279C95 |
Engine Immobiliser System Incorrect Assembly |
A hybrid vehicle control ECU that is incompatible with the immobiliser function is installed. (1-trip detection logic*) |
Hybrid vehicle control ECU |
- |
- *: Only detected while a malfunction is present.
Vehicle Condition and Fail-safe Function when Malfunction Detected |
Vehicle Condition when Malfunction Detected |
Fail-safe Function when Malfunction Detected |
|
Hybrid control system cannot be started |
- |
Related Data List and Active Test |
DTC No. | Data List and Active Test |
|
B279C95 | - |
CAUTION / NOTICE / HINT
NOTICE:
- When using the Techstream with the power switch off, connect the
Techstream to the DLC3 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 Key.
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.
- The smart key system (for Start Function, HV Model) uses the LIN
communication system and CAN communication system. Inspect the
communication function by following How to Proceed with Troubleshooting.
Troubleshoot the smart key system (for Start Function, HV Model) after
confirming that the communication systems are functioning properly.
Click here 
- Before replacing the hybrid vehicle control ECU, refer to Registration.
Click here
- After performing repairs, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".
PROCEDURE
|
1. | REPLACE HYBRID VEHICLE CONTROL ECU |
(a) Temporarily replace the hybrid vehicle control ECU with a new one.
Click here
| NEXT |
 | END (HYBRID VEHICLE CONTROL ECU WAS DEFECTIVE) |
Ignition Hold Monitor Malfunction (B2271)
DESCRIPTION
This DTC is
stored when a malfunction in the IG circuit or IG hold circuit of the
certification ECU (smart key ECU assembly) is detected.
|
DTC No. | Detection Item |
DTC Detection Condition | Trouble Area |
Note |
| B2271 |
Ignition Hold Monitor Malfunction |
When either of the following conditions is met (1-trip detection logic*1):
- The IG circuit of the certification ECU (smart key ECU assembly) is malfunctioning.*2
- The IG hold circuit of the certification ECU (smart key ECU assembly) is malfunctioning.*3
|
- Certification ECU (smart key ECU assembly)
- Wire harness or connector
|
- Turn the power switch on (IG).
|
- *1: Only detected while a malfunction is present and the power switch is on (IG).
- *2: The IG circuit and IG hold circuit activate the IG relay.
- *3: After the IG circuit turns on, even if the certification ECU (smart
key ECU assembly) malfunctions, the IG hold circuit will maintain the
power source mode in on (IG).
Vehicle Condition and Fail-safe Function when Malfunction Detected |
Vehicle Condition when Malfunction Detected |
Fail-safe Function when Malfunction Detected |
|
The power switch cannot be turned on (IG) (the hybrid control system cannot be started). |
The power source mode cannot be changed to on (IG). |
Related Data List and Active Test Items |
DTC No. | Data List and Active Test |
|
B2271 | Power Source Control
- IG Relay Monitor (Inside)
- Latch Circuit
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- When using the Techstream with the power switch off, connect the
Techstream to the DLC3 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 Key.
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.
- The smart key system (for Start Function, HV Model) uses the LIN
communication system and CAN communication system. Inspect the
communication function by following How to Proceed with Troubleshooting.
Troubleshoot the smart key system (for Start Function, HV Model) after
confirming that the communication systems are functioning properly.
Click here 
- Before replacing the certification ECU (smart key ECU assembly), refer to Registration.
Click here
- After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".
PROCEDURE
|
1. | CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
| (a) Measure the voltage according to the value(s) in the table below.
Standard Voltage: |
Tester Connection | Condition |
Specified Condition | |
G40-17 (IG1D) - Body ground |
Power switch on (ACC) → Power switch on (IG) |
1 V or less → 9 V or higher | |
 |
|
*a | Component with harness connected (Certification ECU (Smart Key ECU Assembly)) | | |
| OK |
 | END (TEMPORARY CONNECTION FAILURE IS SUSPECTED) |
| NG |
| REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
