DESCRIPTION
If the communication line (EFIO-IMI) to the transponder 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 |
Communication line (EFIO-IMI) between the ECM and transponder key ECU assembly is stuck high output. |
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
PROCEDURE
1. |
CHECK DTC OUTPUT |
(a) 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 DTC CHART |
|
2. |
CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - ECM) |
(a) Disconnect the transponder 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 |
---|---|---|
D22-13 (EFIO) - A41-40 (IMI) |
Always |
Below 1 Ω |
D22-13 (EFIO) - Body ground |
Always |
10 kΩ or higher |
A41-40 (IMI) - Body ground |
Always |
10 kΩ or higher |
Tester Connection |
Condition |
Specified Condition |
---|---|---|
D22-13 (EFIO) - A49-11 (IMI) |
Always |
Below 1 Ω |
D22-13 (EFIO) - Body ground |
Always |
10 kΩ or higher |
A49-11 (IMI) - Body ground |
Always |
10 kΩ or higher |
Standard Voltage:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
D22-13 (EFIO) - Body ground |
Always |
Below 1 V |
*1 |
Front view of wire harness connector (to Transponder 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 TRANSPONDER KEY ECU ASSEMBLY (OUTPUT) |
(a) Reconnect the transponder key ECU assembly connector.
(b) Reconnect the ECM connector.
(c) Using an oscilloscope, check the waveform. Waveform 1 (Reference):
Result:
|
|
B | ![]() |
REPLACE ECM |
C | ![]() |
REPLACE ECM |
|
4. |
REPLACE TRANSPONDER KEY ECU ASSEMBLY |
(a) Replace the transponder key ECU assembly (See page
).
|
5. |
REGISTER KEY |
(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 (TRANSPONDER KEY ECU WAS DEFECTIVE) |
B | ![]() |
REPLACE ECM |
C | ![]() |
REPLACE ECM |
On-vehicle Inspection
ON-VEHICLE INSPECTION
PROCEDURE
1. INSPECT COOLING FAN OPERATION AT LOW TEMPERATURES (Below 83°C (181°F))
(a) Turn the ignition switch to ON.
(b) Check that the cooling fans stop.
If not, check the cooling fan relays and engine coolant temperature senso ...
Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
HINT:
Use the table below to help determine the cause of problem symptoms.
If multiple suspected areas are listed, the potential causes of the symptoms
are listed in order of probability in the "Suspected Area" ...
GCWR, TWR and Unbraked TWR
Confirm that the gross trailer weight, gross combination weight, gross vehicle
weight, gross axle weight and tongue weight are all within the limits.
- GCWR* and TWR*
► Vehicles without towing package
► Vehicles with towing package
...