DTC 256
RSE OCC fault
• DTC 256 is set by the ECM when the OCC test has failed after the KOEO Standard Test has been run.
• DTC 256 can be set when a poor connection, an open or short to ground in the relay control circuit, or failed relay exists.
• When DTC 256 is active the amber ENGINE lamp is illuminated.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
