Baud: 19200 8-N-1
Commands: Sent as strings with new-line termination

• A[O][V]
  • Fuel Correction Table
    • [O] - Hex offset into the correction table array
    • [V] - Hex value [signed byte] to store at the offset
  • Examples
    • A0000 - Set value at offset 0x00 to 0x00 [0% correction]
    • AEE29 - Set value at offset 0xEE to 0x29 [16% correction]
    • AEEF8 - Set value at offset 0xEE to 0xF8 [-3.1% correction]
  • Response
    • No expected response from the ECU
• B
  • Diagnostic Information
  • Response
    • [ECU CODE],D,[Test Flags],[I/O Flags],[Error Flags]
• C[I]
  • Configuration Tables
    • [I] - Single character index into the configuration tables
  • Tables
    • 0 - Basic ECU Configuration
      • Response
        • [ECU CODE],C,0,S,[Injector Size Flags],[Staging RPM],M,[I/O Flags],[ATP Correction],[VRES Correction],[EGR Output RPM],L,[Comma Separated RAM Offsets for Logging]
    • 1 - Fuel Correction Table
    • 2 - Leading Ignition Table
    • 3 - Trailing Ignition Table
    • 5 - Cranking Fuel Table
• D
  • ​​​​​​​Datalog Request
  • Reponse
    • [ECU CODE],L,[Counter],[Comma Separated RAM Values]
• ​​​​​​​​​​​​​​G[V]
  • VRES Correction
    • [V] - Hex value [byte] used to emulate a static VRES voltage
  • Examples
    • G00 - Set VRES to 0V
    • G80 - Set VRES to 2.5V
    • GFF - Set VRES to 5V
  • Response
    • No expected response from the ECU
• ​​​​​​​​​​​​​​H[V]
  • ATP Correction
    • [V] - Hex value [byte] used to emulate a static ATP voltage
  • Examples
    • H80 - Set ATP to 2.5V [~10k feet]
    • HA6 - Set ATP to 3.25V [~5k feet]
    • HCD - Set ATP to 4V [~0k feet]
  • Response
    • No expected response from the ECU
• I
  • ​​​​​​​Restore ECU Defaults
  • Response
    • No expected response from the ECU
• J[V]
  • ​​​​​​​EGR Output RPM
    • [V] - Hex value [byte] representing a scaled RPM
  • Response
    • No expected response from the ECU
• K[O][V]
  • ​​​​​​​Cranking Fuel Map
    • [O] - Hex offset into the map array
    • [V] - Hex value [byte] to store at offset
  • Response
    • No expected response from the ECU
• L+[O]
  • ​​​​​​​Logging Parameters
    • [O] - Hex offset [byte] into RAM to read during datalog request
  • Response
    • No expected response from the ECU
• O[F]
  • ​​​​​​​Output Configuration
    • [F] - Hex flag [byte] representing output configuration
  • Response
    • No expected response from the ECU
• R[V]
  • ​​​​​​​Staging RPM
    • [V] - Hex value [byte] representing a scaled RPM
  • Response
    • No expected response from the ECU
• S[F]
  • Injector Sizing
    • [F] - Hex flag [byte] representing injector configuration
  • Response
    • No expected response from the ECU
• TL[O][V]
  • ​​​​​​​Leading Timing
    • [O] - Hex offset into the timing array
    • [V] - Hex value [byte] to store at offset
  • Response
    • No expected response from the ECU
• TT[O][V]
  • ​​​​​​​Trailing Timing
    • [O] - Hex offset into the timing array
    • [V] - Hex value [byte] to store at offset
  • Response
    • No expected response from the ECU
• V
  • ​​​​​​​Version Information
  • Response
    • [ECU CODE],V,[VERSION],[SERIAL NUMBER]
• Z
  • Clear Logging Paramaters
  • Response
    • No expected response from the ECU

 

That's impressive

 

remember the protocol and values are similar but not the same depending on ECU model, or even the version of the same model

 

Indeed. I've only tested the above basic "protocol" against the S4 NA/TII 2.1. I validated most of the above simply by creating an emulator and simulating communication/continuity with the RTEK software itself -- it should be fairly trivial to work backwards and identify variation with the earlier releases using the same methodology.

I have almost all of the flags, variables, RAM offsets, conversions, and so forth documented fairly well for the S4 NA/TII 2.1, I'm just not quite sure of a "simple" way of presenting all of that data in a clean format, so I've omitted it thus far.

 

Thanks, I'll try this with my Android app I'm working on.