DESCRIPTION
If the communication line (IMI - EFIO) between the ECM and ID code box (immobiliser code ECU) is stuck high, the ECM 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 ECM and ID code box (immobiliser code ECU) is stuck high. (1 trip detection logic*) |
| DTC output confirmation operation:
|
Vehicle Condition when Malfunction Detected | Fail-safe Operation when Malfunction Detected |
---|---|
Engine cannot be started | Engine cannot be started |
DTC No. | Data List and Active Test |
---|---|
B279A12 | - |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Click here
HINT:
When DTC B279A12 and a certification ECU (smart key ECU assembly) DTC are output simultaneously, first perform troubleshooting for the certification ECU (smart key ECU assembly) DTC.
PROCEDURE
1. | CLEAR DTC |
(a) Clear the DTCs.
Powertrain > Engine > Clear DTCs
|
2. | CHECK FOR DTC |
(a) Turn the engine switch on (IG) and wait 10 seconds.
(b) Check for DTCs.
Powertrain > Engine > Trouble CodesHINT:
If DTCs other than DTC B279A12 are output, troubleshoot those DTCs first.
Result | Proceed to |
---|---|
Only DTC B279A12 is output | A |
DTC B279A12 and other DTCs are output | B |
B | ![]() | GO TO DIAGNOSTIC TROUBLE CODE CHART |
|
3. | CHECK CONNECTION OF CONNECTOR |
(a) Turn the engine switch off.
(b) Check that the connectors are properly connected to the ECM and ID code box (immobiliser code ECU).
OK:
Connectors are properly connected.
NG | ![]() | CONNECT CONNECTORS PROPERLY |
|
4. | CHECK HARNESS AND CONNECTOR (ID CODE BOX (IMMOBILISER CODE ECU) - ECM) |
(a) Disconnect the J36 ID code box (immobiliser code ECU) connector.
(b) Disconnect the A37 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
J36-4 (EFIO) - A37-59 (IMI) | Always | Below 1 Ω |
J36-4 (EFIO) or A37-59 (IMI) - Body ground | Always | 10 kΩ or higher |
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
5. | REPLACE ID CODE BOX (IMMOBILISER CODE ECU) |
(a) Replace the ID code box (immobiliser code ECU) with a new one.
Click here
|
6. | REGISTER ECU COMMUNICATION ID |
(a) Register the ECU communication ID code.
Click here
|
7. | CHECK WHETHER ENGINE STARTS |
(a) Check that the engine starts.
OK:
Engine starts normally.
NG | ![]() | REPLACE ECM |
|
8. | CLEAR DTC |
(a) Clear the DTCs.
Powertrain > Engine > Clear DTCs
|
9. | CHECK FOR DTC |
(a) Perform "DTC Output Confirmation Operation" procedure.
(b) Check for DTCs.
Powertrain > Engine > Trouble CodesOK:
DTC B279A12 is not output.
OK | ![]() | END (ID CODE BOX (IMMOBILISER CODE ECU) WAS DEFECTIVE) |
NG | ![]() | REPLACE ECM |
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