I recently replaced ecm, spark plugs, wires, coil, new injector and it still is misfiring with check engine light and p0201 and p301 codes... I need to smog my van and dont know what could be causing this
My car has an automatic transmission.
Hi there. As you already know, replacing components without diagnoses can be expensive and time consuming without resolution. Circuit testing for the P0201 (#1 cylinder injector circuit fault) code needs to be performed to isolate the injector circuit fault. This could be done using an DVOM (digital, volt , ohm, meter), checking for a voltage signal to the injector and a resistance value test from the injector to the ECM (engine control module). Resolving the P0201 code, more than likely, will resolve the P0301 (#1 cylinder misfire) code. I recommend having your vehicle’s check engine light be diagnosed and repaired by a certified technician, such as one from YourMechanic.