U0420 BMW Fault Code

Description:

Throttle Position (TP) Sensor Intermittent The TP sensor circuit is monitored by the PCM for sudden BMW TP rotation angle (or voltage) input change through the comprehensive component monitor (CCM). If during the last 80 warm-up cycles in key ON engine running the BMW PCM detects a TP rotation angle (or voltage) changes beyond the minimum or maximum calibrated limit, a continuous diagnostic trouble code (DTC) is stored. Poor continuity through the TP sensor connectors Poor continuity through the TP harness Intermittent open or short inside the TP sensor While accessing the TP V PID on the scan tool, lightly tap on the TP sensor or wiggle the TP sensor connector and harness.

U0420 Code Symptoms :

OBD U0420 code and tailpipe testing are two different approaches to identify vehicles in need of repair. The OBD system looks for broken or malfunctioning emissions control components and U0420, while tailpipe tests sample a vehicle's exhaust to see if it is above or below certain prescribed limits. Given the robust nature of today's emissions control components, it is entirely possible for an individual component to malfunction without leading to an immediate increase in emissions at the tailpipe.

In such cases, other components (like the catalyst) can temporarily compensate for the part that is broken however, these other components can only do double duty for so long before they, too, begin to malfunction. In addition, OBD also monitors for and other malfunctions in the fuel system problems that traditional tailpipe tests were not designed to identify. Most state and local areas also include a gas cap pressure test as part of an emission inspection.

Diagnosis And Repairing U0420

U0420 OBD2 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.

How to fix U0420 code ?

• Air fuel ratio (A/F) Sensor 1 Bank 1 circuit poor electrical connection
• Faulty Intake Valve Timing Control Solenoid Valve
• Faulty Intake Valve Timing Control Solenoid Valve
• Oil flow restriction in the oil passages or the VCT valve body

One example of this would be when an bmw automatic car in placed in gear. To prevent the added drag from the torque converter and transmission from reducing the idling speed, the PCM will command the idle control valve to allow more air to enter the engine, while at the same time, adjusting the injector pulse width to inject more fuel to suit the increased amount of air. Note that the idle air control valve is closed by the PCM when the throttle plate is opened to prevent excess air from entering the engine.