U3821 Engine Code Repair

Meaning of U3821 engine trouble code is a kind of network trouble code and when the check engine light comes U3821 code on the first you should check is the gas cap. Pull over, retighten it, and take a look at the cap to see if it has any cracks in it. Continue driving and see if the check engine light turns off. Alternately, you can purchase a gas cap for about $3 at an auto parts store. All you need to do is take the old one off and screw on the new one. If you've already made it to the store, you might as well just replace it. While not car-threatening, it's good to take care of this right away to improve gas mileage.

U3821 Fault Symptoms :

U3821 Possible Solution:

Air Conditioning Pressure Sensor (ACP) Insufficient Pressure Change Each time the A/C clutch engages, the PCM is looking for a pressure change in the refrigerant. If the change in pressure is outside of the calibration the DTC will set. A/C system mechanical failure Open ACP or VREF circuit A/C sensor damaged A/C system electrical failure A/C clutch always engaged Verify A/C system function, including refrigerant charge.

U3821 Code Meaning :

The poor running symptoms are consistent with a MAP sensor malfunction. In addition, in some cases, a bad MAP sensor will not throw a code. Again, the ELD code likely represents a separate wiring issue.

U3821 DTC specifically refers to the camshaft (cam) timing. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set.