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U3940 Engine Trouble Code

Meaning of U3940 engine trouble code is a kind of network trouble code and U3940 if your catalytic convertor fails completely, you eventually won't be able to keep the car running. Your gas mileage will also be terrible, so you should try and fix it as soon as you can. Unfortunately, the average replacement cost is around $2,140 and you can't do it yourself unless you're an experienced mechanic.

U3940 Fault Symptoms :

Check engine light comes on
Engine stalling or misfiring
Engine performance issues
Car not starting

If one of these reasons for U3940 code is occuring now you should check U3940 repair processes.
Now don't ask yourself; What should you do with U3940 code ?
The solution is here :

U3940 Possible Solution:

Disconnected, dirty or fouled spark plugs are common causes for engines that won't start. Spark plugs typically need to be replaced every season or 25 hours of use. You should also check that the spark plug gap is set properly. If your spark plugs look good, problems with your ignition system can also preventing a spark. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage.

U3940 Code Meaning :

U	3	9	4	0
OBD-II Diagnostic Network (U) Trouble Code For Engine	Ignition System Or Misfire	Injector Circuit Malfunction - Cylinders	Injection lump Fuel Metering Control 'B' High (Cam/Rotor/Injector)	Shift Solenoid E Performance or Stuck Off

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate.

U3940 OBD-II Diagnostic Network (U) Trouble Code Description

U3940 engine trouble code is about Shift Solenoid E Performance or Stuck Off.

Main reason For U3940 Code

The reason of U3940 OBD-II Engine Trouble Code is Injector Circuit Malfunction - Cylinders.

U3940 DTCs may also be triggered by faults earlier down the line. For example, a dirty MAF sensor might be causing the car to overcompensate in its fuel-trim adjustments. As a result, oxygen sensors are likely to report fuel mixture problems.

	Example: 0140