Codes P0335,P0340 & P0421 are causing the check engine light stay on. Can all these be connected as a whole or are they 3 different problems? Any tips on where to begin? Also when car is cold it shoots the rpm up .
My car has 191000 miles.
My car has an automatic transmission.
The 335 and 340 codes are for crankshaft and camshaft circuits. This could be bad sensors, or it could be an issue in the wiring to the sensors. The 421 is for a catalyst performance. It can come up because of a bad catalyst or because of a bad rear oxygen sensor. All of these codes could be connected and the common link may be in the wiring harness. Check the condition of the harness on the engine compartment and the exhaust especially the ground connections. If you don’t find anything there, you will need some real diagnostic work. Contact YourMechanic to have a technician come out to your home or office to check out your Mitsubishi and let you know what is the solution.
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