Read All EEPROMCheck current supported values
MG Flasher DiagnosticsCustom Code
Custom Code
Diagnostics
Read installed On-The-Fly settings, set supported feature states and verify what the ECU is currently using. MG Flasher calls the underlying DME software Custom Code; the controls shown here depend on the version and features installed on the connected ECU.
Compatible Custom Code v6.9.0 or newer is required. Custom Code is MG Flasher software installed inside the DME. Later controls appear only when supported by the ECU, installed version and configuration.
Diagnostics Overview
Read. Set. Save.
App Navigation
My Car→Open Car→Diagnostics→Custom Code Diagnostics
Set Feature ValuesAdjust available On-The-Fly states
Save EEPROMInitiate long-term storage
Confirm Feature StateCheck settings without using steering-wheel controls
Important
Set All EEPROM is intended for controlled troubleshooting and should not be used as a general setup shortcut.
OverviewSee What the ECU
See What the ECU
Is Actually Using.
Custom Code Diagnostics provides a direct app-based view of supported On-The-Fly values used by the ECU. It is especially useful when steering-wheel controls are unavailable, a feature state is unclear or troubleshooting requires a known value to be read or set.
The page does not automatically show every possible MG Flasher feature. The available cards and controls are generated according to the Custom Code version and functionality supported by the connected vehicle.
What it is
An in-app diagnostic interface for supported On-The-Fly settings
Reads supported statesCheck slots, toggles, RPM setpoints and selected values stored by the ECU.
Sets supported valuesChange selected feature values without navigating the steering-wheel menu.
Supports troubleshootingConfirm whether an issue is related to feature state, input method or compatibility.
Feature-State Diagnostics
Custom Code Diagnostics
Read or set supported On-The-Fly values such as map slots, Max Cooling status, Anti-Lag RPM, ethanol override and compatible flap or Valet states.
My Car → Open Car → Diagnostics → Custom Code Diagnostics
Fault-Code Diagnostics
Read DTCs
Read diagnostic trouble codes when the Check Engine Light remains illuminated, a protection event is recorded or an ECU fault needs to be investigated.
My Car → Open Car → Diagnostics → Read DTCs
Version Availability
Controls Expand with Custom Code.
The exact diagnostic tools depend on the release installed on the connected ECU.
General OTF Controls
Custom Code Diagnostics becomes available, including supported Switchable Maps, Burbles, Max Cooling and EEPROM tools.
Anti-Lag Diagnostics
Read or set the supported stationary Anti-Lag RPM setpoint through the diagnostics workflow.
Ethanol, Exhaust Flap & Valet
Ethanol Override, Exhaust Flap and Valet Mode diagnostics become available where supported. Radiator Flap is shown only on compatible vehicle and ECU setups.
ECU software still matters.
A vehicle may support Custom Code, but the exact available release depends on its SWFL and ECU platform.
General Diagnostics
Read and Manage Saved On-The-Fly Values.
Start with a read operation before changing or saving any feature state.
01
Recommended First StepRead All EEPROM
Check the current values and status of all supported Custom Code On-The-Fly options exposed by the installed version.
02
Troubleshooting OnlySet All EEPROM
Set available slots and statuses to predefined values. This tool is intended for controlled troubleshooting rather than normal daily adjustment.
03
Long-Term StorageSave EEPROM
Perform the ignition-cycle process used to initiate long-term storage of supported On-The-Fly values.
1Set a supported value
→2Ignition OFF
→3Wait approximately 5 seconds
→4Ignition ON to trigger storage
Feature Diagnostics
Read and Set Supported On-The-Fly Features.
Each diagnostic card appears only when the installed Custom Code version and vehicle support it.
Switchable Maps
Read the active map slot and select a supported valid slot directly from the diagnostic page.
Explore Switchable Maps →Burbles
Read or set the active Burble slot. Slot 5 is available only with Custom Code v7.1 or newer.
Explore Burbles →Max Cooling
Read the current Max Cooling status and enable or disable the function where supported.
Explore Max Cooling →Anti-Lag RPM
Read the active stationary Anti-Lag RPM setpoint or set a supported value from the app.
Explore Anti-Lag →Ethanol Override
Read the override status and value, enable or disable the override and set a supported ethanol percentage up to E75.
Explore Ethanol Content →Exhaust Flap
Check the current state or select OEM, Closed or Open on compatible vehicles.
Explore Exhaust Flap →Radiator Flap
Read the current state or select OEM, Closed or Open on compatible vehicles with factory radiator flaps. This function has no CCM tachometer position.
Explore Radiator Flap →Valet Mode
Check the active Valet Mode status and enable or disable it through the diagnostic interface.
Explore Valet Mode →
Control Methods
Diagnostics, App Control or Steering-Wheel Control?
All three methods can interact with supported On-The-Fly settings, but they are designed for different situations.
Custom Code Diagnostics
Best for reading current EEPROM values, confirming feature state and setting known values during diagnosis.
- Direct read and set commands
- Version-dependent diagnostic cards
- EEPROM save workflow
Live Control
Designed for fast, real-time adjustment of available features while connected to the vehicle.
- Polling and synchronization
- Toggles, slots, sliders and selectors
- Validity and feature gating
Custom Code Menu (CCM)
Uses compatible steering-wheel inputs, the tachometer and Check Engine Light as a temporary in-car feature menu.
- No phone interaction for supported actions
- UniRocker or RockerCombo
- Feature submenus and counted Check Engine Light blinks
Troubleshooting Workflow
Confirm the State Before Reflashing.
When a feature does not respond through CCM, the problem may be the stored value, unsupported button configuration, feature codeword, Custom Code version or vehicle compatibility.
Custom Code Diagnostics helps separate a control-input problem from a feature-state problem by allowing supported values to be read and set directly through the app.
01
Connect and read current values Do not assume which state, slot or setpoint is currently stored.
02
Confirm the installed Custom Code version Some diagnostic controls require Custom Code v7.0 or v7.1 and newer.
03
Set one known test value Use the individual feature diagnostic where available instead of changing every EEPROM value.
04
Save only when required Use the documented ignition-cycle procedure when the value must be written to EEPROM.
05
Read DTCs when the CEL stays illuminated A continuously illuminated Check Engine Light beyond the configured CCM timeout may indicate an actual ECU fault.
Check Engine Light meaning
CCM feedback or an actual DTC?
Slow, fast and counted CEL blinks can be intentional Custom Code feedback. However, if the Check Engine Light remains continuously illuminated longer than the CCM timeout configured during flashing, treat it as a possible OEM ECU fault rather than menu confirmation.
Read the stored diagnostic trouble codes before reflashing or changing multiple feature values.
My Car→Open Car→Diagnostics→Read DTCs
Intentional Custom Code feedback
Slow, fast or counted blinking associated with CCM and supported On-The-Fly functions.
Possible ECU fault
CEL remains continuously illuminated after the configured CCM timeout has elapsed.
Compatibility
The Installed Software Defines the Tools You See.
Availability depends on the vehicle, ECU software, installed Custom Code release and enabled features.
Supported Vehicle
The connected engine platform and ECU must support MG Flasher Custom Code.
Custom Code v6.9+
The base Custom Code Diagnostics page requires version 6.9.0 or newer.
Feature Version
Anti-Lag diagnostics require v7.0+. Ethanol Override, Exhaust Flap and Valet Mode require v7.1+. Radiator Flap also requires a compatible vehicle and ECU setup.
Direct Car Connection
The latest MG Flasher app must be connected through a supported ENET WiFi adapter or cable.
Important Notes
Diagnostics Does Not Add Missing Features.
A diagnostic control can only interact with functionality that exists and is supported in the installed Custom Code configuration.
Not Enabled in the Installed Software
If a feature codeword is disabled, the related control may be unavailable until the configuration is updated and reflashed.
Unsupported Version
A newer diagnostic card will not appear when the connected ECU uses an older Custom Code release.
Read Before Set
Review the current value before making changes so the previous state is known.
Use Support When Unsure
Do not use troubleshooting-wide commands when an individual feature diagnostic or support instruction is more appropriate.
Legal & Responsible Use
Review Terms & ConditionsDiagnostic Changes Can Affect Vehicle Behaviour.
Read the current value before making changes and perform diagnostic adjustments while the vehicle is stationary. Feature availability does not confirm that a setting is legal or suitable for public-road use.
Vehicle tuning and software modifications may be restricted by local emissions, noise, road-use or motorsport regulations. The vehicle owner and user are responsible for legal compliance, vehicle condition and safe operation.
FAQ
Custom Code Diagnostics FAQ.
Common questions about versions, EEPROM values, feature controls and troubleshooting.
What is Custom Code Diagnostics?
It is an MG Flasher app page that reads and sets supported On-The-Fly values used by compatible software installed inside the DME.
What does Custom Code mean?
Custom Code is MG Flasher software installed inside a compatible DME. It enables selected On-The-Fly controls, integrations, diagnostics and protection logic.
Is Custom Code Diagnostics where I read fault codes?
No. Custom Code Diagnostics is primarily for supported feature values and EEPROM states. Use Diagnostics → Read DTCs to investigate diagnostic trouble codes and ECU faults.
Which Custom Code version is required?
The base Custom Code Diagnostics feature requires Custom Code v6.9.0 or newer. Individual controls may require later versions.
Where can I find Custom Code Diagnostics?
Connect to the vehicle and navigate through My Car → Open Car → Diagnostics → Custom Code Diagnostics.
Can I change Switchable Maps from this page?
Yes, where supported. You can read the active slot and select an available valid slot through the Switchable Maps diagnostic control.
Can I configure Anti-Lag RPM?
Anti-Lag diagnostics are available on compatible Custom Code v7.0 or newer configurations and can read or set the supported stationary RPM setpoint.
Can I set Ethanol Override from diagnostics?
Yes, on compatible Custom Code v7.1 or newer setups. You can read the active status and value, enable or disable the override and set a supported value up to E75.
What does Read All EEPROM do?
It reads the available stored values and status of supported Custom Code On-The-Fly features exposed by the connected ECU.
What does Save EEPROM do?
It initiates the ignition-cycle process used to save supported On-The-Fly values into long-term ECU storage.
Is Custom Code Diagnostics the same as Live Control?
No. Diagnostics is focused on reading, setting and troubleshooting values, while Live Control is designed for faster real-time daily interaction and synchronization.
Why is a feature missing from the page?
The feature may not be supported by the connected vehicle, installed Custom Code version or current configuration.
Need to Check a Feature State?
Connect and Read On-The-Fly Settings.
Use the MG Flasher app to identify the installed software and access the feature-state diagnostics available for your vehicle.