DESCRIPTION
If the communication line (EFIO - IMI) to the certification ECU (smart key ECU assembly) is stuck high output (e.g. shorted to +B), the ECM stores this DTC.
DTC No. |
DTC Detection Condition |
Trouble Area |
---|---|---|
B279A |
When the communication line (EFIO - IMI) between ECM and certification ECU (smart key ECU assembly) is stuck high output. |
|
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 ).
HINT:
If any DTCs other than DTC B279A are output, troubleshoot those DTCs first.
Result |
Proceed to |
---|---|
DTC B279A is output |
A |
DTC B279A and other DTCs are output |
B |
B |
GO TO DIAGNOSTIC TROUBLE CODE CHART |
|
2. |
CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ECM) |
(a) Disconnect the certification ECU (smart key ECU assembly) connector.
(b) Disconnect the ECM connector. |
|
(c) Measure the resistance and voltage according to the value(s) in the table below.
Standard Resistance:
for 2GR-FE
Tester Connection |
Condition |
Specified Condition |
---|---|---|
D25-35 (EFIO) - A41-40 (IMI) |
Always |
Below 1 Ω |
D25-35 (EFIO) - Body ground |
Always |
10 kΩ or higher |
Tester Connection |
Condition |
Specified Condition |
---|---|---|
D25-35 (EFIO) - A49-11 (IMI) |
Always |
Below 1 Ω |
D25-35 (EFIO) - Body ground |
Always |
10 kΩ or higher |
Standard Voltage:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
D25-35 (EFIO) - Body ground |
Always |
Below 1 V |
*1 |
Front view of wire harness connector (to Certification ECU (Smart Key ECU Assembly)) |
*2 |
Front view of wire harness connector (to ECM) |
*3 |
for 2GR-FE |
*4 |
for 1AR-FE |
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 ECM connector.
(c) Using an oscilloscope, check the waveform.
Waveform (Reference):
Item |
Content |
---|---|
Terminal No. (Symbol) |
D25-35 (EFIO) - D25-15 (E) |
Tool Setting |
5 V/DIV., 100 msec./DIV. |
Condition |
Engine switch on (IG) |
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 |
B |
REPLACE ECM |
C |
REPLACE ECM |
|
4. |
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) |
(a) Replace the certification ECU (smart key ECU assembly) (See page ).
|
5. |
KEY REGISTRATION |
(a) Register the key (See page ).
|
6. |
REGISTER ECU COMMUNICATION ID |
(a) Register the ECU communication ID (See page ).
|
7. |
CHECK DTC OUTPUT |
(a) Clear the DTCs (See page ).
(b) Recheck for DTCs (See page ).
OK:
DTC B279A is not output.
Result |
Proceed to |
---|---|
OK |
A |
NG (for 2GR-FE) |
B |
NG (for 1AR-FE) |
C |
A |
END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE) |
B |
REPLACE ECM |
C |
REPLACE ECM |
Engine (ignition) switch (vehicles without smart key system)
- Starting the engine
Check that the parking brake is
set.
Check that the shift lever is set
in “P”.
Sit in the driver’s seat and firmly
depress the brake pedal.
Turn the engine switch to the “START”
position and start the engine ...
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REMOVAL
CAUTION / NOTICE / HINT
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Then remove the brake master cylinder from the brake booster.
PROCEDURE
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On-vehicle Inspection
ON-VEHICLE INSPECTION
PROCEDURE
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(a) Remove the taillight relay from the main body ECU (driver side junction
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(b) Measur ...