U0120 Mercedes X Class OBD Code

OBD/2 U0120 error code description and symptoms.

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.

Gear changes are accomplished by a command from the TCM to energize the clutch actuator to release the clutch; after which various actuators inside the transmission disengage the current gear, and depending on current operating conditions, engage the next higher or lower gear ratio. All of this happens much faster than a human driver could change gears, and in most applications, gear changes are as smooth and seamless as on any fully automatic transmission.

U0120 Mercedes X Class Error Code Repair Process :

OBD U0120 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 scp (j1850) invalid or missing data for primary id, 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 U0120 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 U0120 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.

Common Causes of Mercedes X Class U0120 OBD2 Code

A common cause of code U0120 is the failure of SCP (J1850) Invalid or Missing Data for Primary Id, but there are several other possible causes as well, such as ;

Dirty Oil
Faulty Camshaft Position Sensor
Fuel injector leaks
Faulty Air Flow Meter

U0120 is a kind of Network Trouble Code

U-code indicates that engine communication errors and shows lost communication with engine parts.U-Codes are fairly straight forward, given all of the articles and technical publications that have been written regarding these problematic codes. In most cases, it just comes down to identifying the module that isn't communicating with the other modules on the CAN bus line for whatever reason.

Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.

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U0120 Mercedes X Class OBD Code

U0120 Mercedes X Class Error Code Repair Process :

Common Causes of Mercedes X Class U0120 OBD2 Code

U0120 code for other Mercedes cars