U1020 BMW Auto Trouble Code

Parts or components should not be replaced with reference to only a U1020 BMW DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing.

The problem is caused by the variable cylinder management system switching on and off during light throttle conditions, at cruising speeds, or when driving on flat roads. The constant switching causes excessive oil consumption and the trouble codes appear when oil pressure drops to the point where it can no longer operate the VCM system.

U1020 BMW Possible Solution:

Gasoline engines use spark plugs to cause an explosion of fuel within the cylinder. In a properly timed engine, this explosion occurs at the proper moment to send the piston to the bottom of the cylinder and provide power to the drive shaft. If the plug wires are out of sequence, the explosion occurs at the wrong time. The improper timing of the explosion sometimes pushes the cylinder the wrong direction or interferes with the turning of the crank. As a result, the engine stutters or backfires, if it runs at all.

U1020 BMW Description For All Models :

U1020 BMW Trouble Repair :

If your vehicle failed a U1020 BMW test and the U1020 BMW Check Engine Light is NOT on, chances are you have a problem with the OBDII system, a burned out MIL lamp, or a faulty catalytic converter. The converter is essentially an afterburner that cleans up the exhaust after it exits the engine. The OBDII system uses a ownstream oxygen sensor to monitor the efficiency of the converter, and it should detect a drop in converter efficiency if the converter has been contaminated or is failing (ignition misfiring, leaky exhaust valves, and oil burning can all damage the converter). What you want to look any conditions that might cause ignition misfire, an overly rich or lean fuel condition, or loss of compression. Use your OBD Express DIY to look at the oxygen sensor outputs, coolant temperature, airflow, calculated engine load, and inlet air temperature.

Code Search

Please fill the search bar to find Auto Trouble Code meaning.

Example: 0120