SYSTEM DIAGRAM
1. DOOR BUS LINES
2. CERTIFICATION BUS LINES (w/ Smart Key System)

System Description
How To Proceed With TroubleshootingEngine Immobiliser System Signal (Some Circuit Quantity, Reported via Serial
Data) Invalid (B279986)
DESCRIPTION
When there are communication malfunctions between the ECM and certification ECU
(smart key ECU assembly), or when the communication ID codes do not match, the ECM
stores this DTC.
DTC Code
DTC Detection Condition
Trouble Area
DTC Output C ...
Removal
REMOVAL
PROCEDURE
1. REMOVE REAR BUMPER ASSEMBLY (w/ Towing Package)
(See page )
2. REMOVE REAR BUMPER ASSEMBLY (w/o Towing Package)
(See page )
3. REMOVE CONNECTOR COVER (w/ Towing Package)
(See page )
4. REMOVE REAR BUMPER HOLE COVER (w/o Towing Package)
(See page )
5. REMOVE REAR ...
Check For Intermittent Problems
CHECK FOR INTERMITTENT PROBLEMS
HINT:
Inspect the vehicle ECM using check mode. Intermittent problems are easier to
detect with the Techstream when the ECM is in check mode. In check mode, the ECM
uses 1 trip detection logic, which is more sensitive to malfunctions than normal
mode (default) ...