John Deere 5246 – ECU: SCR Operator Stage #3 Derate Notification

Informational fault code notifying the operator that the Selective Catalytic Reduction (SCR) system has an active derate timer counting down. Because an underlying emissions issue has not been resolved, the engine is counting down to a final derate. If the countdown finishes, the machine will enter a severe power derate, 5 MPH crawl mode, or forced idle/shutdown.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5090M
• 5100M
• 5100MH
• 5100ML
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6105M
• 8R Series
• 9R Series
• 9470RT
• 9520RT
• 9570RT
• S-Series (S660, S670, S680, S690, S700, S780, S790)
• R-Series Sprayers
• Excavators
• Dozers
• Loaders

1. 1

   Connect John Deere Service ADVISOR (or a compatible heavy-duty diagnostic scanner) to the machine.

2. 2

   Pull all active and stored Diagnostic Trouble Codes (DTCs) from the ECU.

3. 3

   Look for the root-cause emissions codes. Common culprits that trigger the 5246.00 countdown include: DEF Dosing Injector faults, DEF Dosing Unit Pump faults, DOC efficiency low, DPF plugged or incomplete regeneration, and NOx sensor failures.

4. 4

   Check DEF fluid levels and DEF fluid quality.

5. 5

   Inspect the wiring harnesses going to the DEF dosing nozzle and DEF pump for chafing, corrosion, or water intrusion.

1. 1

   Address the Root Cause

   Perform the specific repair dictated by the primary emissions fault code found during diagnostics (e.g., replace a failed DEF dosing injector, replace a faulty NOx sensor, or perform a forced DPF regeneration).

2. 2

   Clear Codes

   Use Service ADVISOR to clear the ECU fault codes.

3. 3

   Perform System Tests

   Run the relevant system tests via the diagnostic tool to verify the repair. For example, if a DEF injector was replaced, run the 'DEF Injector Test' (which fires the nozzle multiple times) and the 'DEF High Flow Test'.

4. 4

   Verify Timer Reset

   Once the ECU verifies that the SCR system is functioning normally and emissions are back within spec, the 005246.00 derate countdown timer will automatically clear and full engine power will be restored.

5. 5

   Unlock ECM

   If the machine was operated until the countdown reached zero and forced a final derate/shutdown, the ECM's EEPROM may lock into a derate state. In severe cases, this requires a dealer-level Service ADVISOR session to unlock, or an ECM cloning/programming service to restore the EEPROM values.