P0821 Engine Trouble Code
When you check engine light came on code P0821 the reason should be Engine Light ON (or Service Engine Soon Warning Light). However your vehicle's manufacturer may have a different definition for the P0821 OBD-II Diagnostic Powertrain (P) Trouble Code. So you should chech it on our car models.
Theoretically you can drive for a few weeks or even months with a broken MAF sensor. You will notice a decrease in gas mileage and over time the car will eventually start stalling a lot. At a shop, the replacement cost is between $200-$300 depending on the car, but that's usually the cost of parts because the labor is relatively simple.
P0821 Code Meaning :
|OBD-II Diagnostic Powertrain (P) Trouble Code For Engine||Intake Valve Control Solenoid Circuit Low||Manifold Absolute Pressure/Barometric Pressure Circuit High Input||Crankshaft Position Sensor A Circuit Malfunction||Glow Plug/Heater Circuit 'A' Malfunction|
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.
P0821 OBD-II Diagnostic Powertrain (P) Trouble Code DescriptionP0821 engine trouble code is about Glow Plug/Heater Circuit 'A' Malfunction.
Reason For P0821 CodeThe reason of P0821 OBD-II Engine Trouble Code is Manifold Absolute Pressure/Barometric Pressure Circuit High Input.
P0821 the main thing to check is to verify the operation of the VCT solenoid. You're looking for a sticking or stuck VCt solenoid valve caused by contamination. Refer to vehicle specific repair manual to perform component tests for the VCT unit.