Catalytic converters must be warm before they can work properly. On a cold start the PCM provides a rich mixture to keep the cold engine running.
All that extra fuel goes into the catalytic converter. But the exhaust isn't very hot, because, ah, the engine is pretty cold. GM has employed several strategies to fire up the catalytic converter quicker and reduce cold start emissions. One way is to use a secondary air pump that pumps outside air directly into the catalytic converter.
Some systems require that the actuator has an adequate supply of brake fluid. Low brake fluid levels can mimic the symptoms of code P3946, so consult the manual to locate the brake fluid reservoir. Bear in mind that a low fluid level can set code P3946 on some applications, so make sure that on fluid operated systems the fluid level is up to the mark before starting an electrical diagnosis.
Difficulty Level (Soso)
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Repair Time (50 Min.)
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Cost Prediction : $ 40-75 |
If your scp (j1850) invalid or missing data for eec programming check engine light is illuminated, it's best to take it in for diagnostic testing, which can feel like a hassle. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There's a problem with the car's emissions system. The on-board diagnostics system P3946 and engine control unit are in charge of monitoring a bunch of different scp (j1850) invalid or missing data for eec programming, and if they get a reading that's a little out of whack, up pops the check engine light.
P3946 is a kind of Powertrain Trouble Code
Powertrain of a modern automobile, comprising engine (with exhaust system), transmission, drive shaft, suspension and the wheels. In a motor vehicle, the term powertrain or powerplant describes the main components that generate power and deliver it to the road surface, water, or air. |
You can view according P3946 DTC for your car model. We selected several models to see obd2 solutions click and view it.
+P3946 Mazda Hakaze | +P3946 Abarth 124 Spider | +P3946 Dacia Stepway | +P3946 Ferrari 312 | +P3946 Chevrolet Volt |