Service Interaction Protocol
Control DTC
RECORD_STATE
PERSISTENCE
SCOPE
Overview
“The ControlDTCSetting service is used by a client to stop or resume the setting of DTCs in the server.”
Practical Use: Technicians use this service during component replacement (like unplugging a battery or sensor) to prevent the vehicle from storing hundreds of “communication lost” or “circuit open” codes that aren’t real faults.
Default Behavior
At ECU power-on, DTC recording is always Enabled by default. Service 0x85 is used to temporarily mute fault recording during maintenance activities. The recording state will automatically revert to Enabled upon any diagnostic session reset or ECU power cycle to ensure no real faults are missed long-term.
Protocol Anatomy (Disable Logging)
◆ PROTOCOL ANATOMY
0x85 CONTROL DTC SETTING
0x85 RESPONSE
DTC Recording Behavior
Internal logic of DTC recording suppression vs. fault detection.
Non-Volatile Persistence: Unlike session states, the DTC disabled state is temporary. ECU power-on always defaults to ENABLED to ensure safety diagnostics are never permanently muted.
Detection != Recording: Even when disabled, the ECU still detects faults. It simply skips the ‘Write to NVRAM’ and ‘Set Status Bit’ steps.
Maintenance Workflow
Workflow: Clean Sensor Replacement
8 stepsNegative Response Codes
Error_Catalog