Technical Service Bulletins

Slow Hyundai rpm drop

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Slow Hyundai rpm drop

This TSB applies to the 2010 Hyundai 2.0L Genesis Coupe. An ECM software update is required on some vehicles to address either of the following conditions:

* MIL ON with DTC P0605 (internal control module ROM error) stored in the ECM. The vehicle may have been operating in the reduced power limp home mode.

* Slow rpm drop when releasing the throttle during gear shift changes or on deceleration from high engine speed.

To verify the vehicle is affected, check the version of the vehicle’s control unit ROM ID with reference to the ROM ID information table below.


MODEL:  Genesis Coupe BK 2.0

ECM P/N (M/T)                    IMMO                                              ROM ID

                                            (smart key)                      Previous                      New

39121-2C090                       YES                                K0C0RG3A            K0C0RH2B

                                                                                    K0C0RH2A            K0C0RH2B

39121-2C110                         NO                                K0C0MG3A           K0C0MH2B

                                                                                    K0C0MH2A           K0C0MH2B

After the ECM update, clear any DTCs from the control units which communicate with each other by CAN-bus, such as ESC, ACU, TPMS and the Smart Key system (the ECM is an immobilizer type if the vehicle has the Smart Key system).

* Make sure that the vehicle battery has reasonable charge. If the vehicle has been in storage, run the engine to assure an adequate battery state of charge for reliable update results. The ECM Update procedure contains a check to assure that battery voltage is above 12 V to allow the procedure to occur.

* The USB cable must be used for ECM update between the GDS and VCI. The procedure will not work in VCI wireless mode.

* Make sure that the GDS laptop battery indicator in the lower right tray has 20% or more charge remaining. If necessary,  charge the laptop battery with the AC adapter cable. Hyundai recommends that the GDS is connected to AC power during reprogramming.

* Turn off all lamps (do not leave the headlamp switch in auto mode). Turn off all accessories (heater, A/C, blower, radio, seat warmer, etc.) to prevent battery discharge during the update.

* Perform the update with the ignition switch in the ON position.

* Be careful not to disconnect any cables connected to the vehicle or scan tool during the update.

* Do not start the engine during the update.

* Do not turn off the ignition switch during the update.

* Make sure that the GDS system has the latest Internet update.


  1. Choose VIN or ECU UPGRADE on the initial screen.
  2. Enter the vehicle information by pressing the VIN Auto Detect button, entering the vehicle’s VIN or selecting the vehicle model, model year, engine/fuel type and ENGINE as the system and then click OK.
  3. Select ECU UPGRADE on the initial screen after entering the vehicle information.
  4. Select Auto Mode, then ENGINE in the left ECU Upgrade column.
  5. Read Preparation and click OK.
  6. The GDS will read the vehicle’s ROM ID.
  7. After the Current ROM ID is displayed, select appropriate Update Event “149.BK 2.0 PUT LEARNING LOGIC IMPROVEMENT.”
  8. After clicking the Upgrade button, read information and then click OK.
  9. The vehicle battery voltage is checked to make sure it is at least 12 V to assure reliable update results. Click OK if the results indicate Voltage is OK.

(NOTE: If voltage is below 12 V, click Cancel and then run the engine to assure an adequate battery state of charge for reliable update results).

  1. The update will begin and the progress of the update will appear on the bar graph.
  2. Update will occur until 100% is reached on the bar graph. Turn the ignition key OFF for 10 seconds, place it back in the ON position and then click OK to continue according to Information displayed on the screen.
  3. Click OK on the final screen, which indicates that the update is complete.
  4. Perform Fault Code Searching for any incidental DTCs that have been created by the update and clear any DTCs. Be sure to clear DTCs from the control units which communicate with each other by CAN-bus.
  5. Start the engine to confirm proper operation.

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