The engine control unit (ECU) in a Toyota Prius is the computer responsible for operating all of the engine's electronic components. This computer monitors data from various sensors throughout the vehicle in order to determine its operational state. When the ECU senses a problem with the engine or one of its related systems it stores a code in its flash memory and turns on the service engine soon (SES) light.Creader CRP229 A computerized scan tool is required to reset these codes and return the computer to its normal state.
Place the car's transmission in park and apply the parking brake. Turn the ignition to the "OFF" position to kill the engine. Rotate the ignition back to the "ON" position, but do not start the engine.UPA USB
Connect the scan tool's data connector to the vehicle's 16-pin diagnostic data port, located underneath the driver's side dashboard/footwell area. Power on the scan tool.
Select "ECU" from the scan tool's main menu. Choose "Codes," then select "Clear all current and stored DTC's." DTC is an abbreviation for "diagnostic trouble codes."
Wait for the scan tool to clear the codes. The display will read "All codes cleared." Unplug the scan tool and start the vehicle.VOLVO VIDA DICE Ensure that the SES light is not turned on. The ECU is now reset.
Nissan cars have become more technologically advanced in recent years. ECU (Engine Control Unit) computers are now an integral part of Nissan car design. The ECU constantly monitors and governs many functions, including the electrical and safety systems of the car, and engine management. When this unit detects a problem, the SES (Service Engine Soon) light on the dashboard turns on to indicate that there's an issue that needs attention. When you take your car in for repair, mechanics can then read codes from the ECU to determine what specific problems exist.UPA USB Programmer After repairs are complete, the SES light must be reset. The SES light in a Nissan is frequently called a check-engine light in other makes.
Open the driver's side door and get into the drivers seat.
Insert the key into the ignition and turn it a quarter turn so the ignition turns on, but the engine doesn't start.
Step on the gas pedal and quickly release it. Do this 5 times in less than 5 seconds.autocom cdp When you step on the pedal, press it down as far as it can go.
Wait 10 seconds.
Press the gas pedal completely down with your foot and hold it there for 10 seconds, or until the SES light blinks on and off.
Step on the gas pedal and hold it down completely for another 10 seconds and then release it.
Turn the ignition key to the off position.
Wait 3 minutes for the ECU to automatically reset.
Start your engine.Digiprog III This will reset the SES light.
Tips & Warnings
This method for resetting the check engine light works on any Nissan model.
Consider taking your Nissan to a mechanic to check your car before resetting the check engine light yourself. Otherwise, the codes he needs may be lost.
Nissan cars have become more technologically advanced in recent years. ECU (Engine Control Unit) computers are now an integral part of Nissan car design. The ECU constantly monitors and governs many functions, including the electrical and safety systems of the car, and engine management. When this unit detects a problem, the SES (Service Engine Soon) light on the dashboard turns on to indicate that there's an issue that needs attention. When you take your car in for repair, mechanics can then read codes from the ECU to determine what specific problems exist.UPA USB Programmer After repairs are complete, the SES light must be reset. The SES light in a Nissan is frequently called a check-engine light in other makes.
Open the driver's side door and get into the drivers seat.
Insert the key into the ignition and turn it a quarter turn so the ignition turns on, but the engine doesn't start.
Step on the gas pedal and quickly release it. Do this 5 times in less than 5 seconds.autocom cdp When you step on the pedal, press it down as far as it can go.
Wait 10 seconds.
Press the gas pedal completely down with your foot and hold it there for 10 seconds, or until the SES light blinks on and off.
Step on the gas pedal and hold it down completely for another 10 seconds and then release it.
Turn the ignition key to the off position.
Wait 3 minutes for the ECU to automatically reset.
Start your engine.Digiprog III This will reset the SES light.
Tips & Warnings
This method for resetting the check engine light works on any Nissan model.
Consider taking your Nissan to a mechanic to check your car before resetting the check engine light yourself. Otherwise, the codes he needs may be lost.
The Engine Control Unit, or ECU, controls the majority of the computer-operated sensors and engine devices on a Nissan Serena.delphi ds150e Fuel and ignition systems are monitored and adjusted using a variety of engine-mounted sensors and feedback. The ECU also stores diagnostic codes for failure analysis and emissions testing. For failures, the ECU codes are stored until the ECU is cleared or may, in some cases, clear following removal of the failure condition. Emissions information is stored in the ECU for retrieval during testing and evaluation of the emissions produced.
ECU Clearing Through Battery Disconnect
Disconnect the negative (black) cable from the car battery terminal, place to the side and ensure it does not touch the vehicle.
Disconnect the positive (red) cable from the car battery terminal, place to the side and ensure it does not touch the vehicle.
Pump the breaks or press the horn several times to drain the remaining power from the vehicle's electrical system.UPA USB Programmer This allows for the capacitors (which store energy) in the ECU to fully deplete.
Leave the cables disconnected for an additional 5 minutes to ensure full depletion of energy from the ECU capacitors, then reconnect the battery cables. The vehicle's ECU will now be reset.
ECU Reset Through ECU Access
Locate the ECU under the driver's side dash of the Nissan. Remove the two nuts (usually 10mm) holding the device in place to fully access the ECU.
Place the starting key into the ignition and turn the key until the electronics mode is engaged. Do not start the vehicle.
Find the screw dial on the ECU. This dial is used to access the stored engine codes.BMW AK90 Key Programmer Place a flat-head screwdriver into the dial and note the position of the screwdriver (not yet turned). The position noted is the original position and will be used to return the ECU to its normal state after clearing the codes.
Turn the dial clockwise until the dial stops turning. Pause one second and turn the dial counterclockwise until the dial stops turning--any error codes present will now be flashing on the dash through a series of blinking/flashing lights.
Turn the dial clockwise until the dial stops turning and wait for the flashing to stop. Once the flashing has stopped, pause one second and return the ECU to its normal state by turning the dial to the original position. The Nissan Serena's ECU should now be cleared. Remove the key from the ignition and return the ECU module to the original position. Install the retaining screws.
I'm posting this hoping it will help someone.
I had a misfire at idle, not very noticeable, no SES light. At 2k rpms in 2nd gear or above the engine would stumble. At 3k+ rpms it would even out and feel fine but not quite as much power as it should have. Pulling codes with INPA showed "A" misfire on exhaust side for cylinders 1,2,3,5 and 6 at 640rpms regularly. Eventually it registered a misfire with "cat damage",Digiprog III or kat damage, around 4k rpms which triggered the SES light and eventually limp mode.
Checked the INPA Run Unrest page, It showed cylinder 3 over 1000, other cylinders also showed very high but not over 1000.
Checked the spark plugs, they were 2-3 years old, maybe 40k on them, nothing stood out. Went ahead and replaced them. No change.
Purchased an ignition coil from advanced auto, carquest if that matters, for testing purposes, fits, but clamp doesn't fit. Bremi on order.
Replaced cylinder 3 ignition coil, no change, cylinder 1, no change, 5 no change.
Finally replaced the cylinder 6 ignition coil,Vagcom 15.7 and the misfire is gone along with the high Run Unrest numbers across the board.
I searched on the board and saw some others with similar issues but theirs either pointed directly to the culprit or did in a round about way. I don't think mine showed any indication of being cylinder 6 as the culprit. I think the lesson here is, check them all.