Complete GM-compatible Class 2 implementation in IMPCO’s powertrain ECU. IMPCO system utilizes a secondary powertrain ECU for running on gaseous fuels. To meet diagnostic/service support requirements, IMPCO ECU had to support complete set of Class 2 commands: reporting of powertrain parameters, trouble codes, security, production and service programming, bootstrap Class 2 J1850 code support.

The following Class 2 Modes (Commands) were implemented:

• Mode $01 - Request Current Powertrain Diagnostic Data
• Mode $02 - Request Powertrain Freeze Frame Data
• Mode $03 - Request Powertrain Diagnostic Trouble Codes
• Mode $04 - Request to Clear/Reset Diagnostic Trouble Codes
• Mode $05 - Request Oxygen Sensor Monitoring Test Results
• Mode $06 - Request On-Board Monitoring Test Results
• Mode $07 - Request Pending Powertrain Trouble Codes
• Mode $08 - Request Control of On-Board System, Test, or Component
• Mode $14 - Clear Diagnostic Information
• Mode $17 - Request Status of Diagnostic Trouble Codes
• Mode $19 - Request DTC Information by Status
• Mode $20 - Return to Normal Mode
• Mode $22 - Request Diagnostic Data by PID
• Mode $27 - Data Link Security Access
• Mode $28 - Disable Normal Message Transmission
• Mode $29 - Enable Normal Message Transmission
• Mode $2A - Request Diagnostic Data Packets
• Mode $2C - Define Diagnostic Data Packet
• Mode $34 - Request Download
• Mode $35 - Request Upload
• Mode $36 - Block Transfer Message
• Mode $3B - Request to Write Data Block
• Mode $3C - Request to Read Data Block
• Mode $3F - Test Device Present
• Mode $7F - General Negative Response
• Mode $A0 - Request High Speed Mode
• Mode $A1- Begin High Speed Mode
• Mode $A2- Programming Prompt
• Mode $AE- Request Device Control