P3870 Trouble Code

View P3870 obd/2 error code description and symptoms. P3870 engine photo

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.

One example of this would be when an automatic vehicle 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.

P3870 Error Code Repair Process :

The rule of P3870 code when it comes to emissions-related vehicle repair is that any modification that changes the vehicle from a certified configuration to a non-certified configuration is considered tampering: this applies to both vehicle owners and repair facilities and is, therefore, a Federal offense. Replacing a catalyst with a straight pipe is one traditional example of air suspension lf height sensor circuit short to ground. Likewise, overriding the OBD P3870 error in system through the use of high-tech defeat devices or non-certified computer chips, for example, would also be considered tampering. The OBD system may, however, be repaired back to its original certified configuration with certified performance chips or appropriate aftermarket parts.

P3870 is a kind of Powertrain Trouble Code

Powertrain of a modern automobile, comprising engine (with exhaust system), transmission, drive shaft, suspension and the wheels. In a motor vehicle, the term powertrain or powerplant describes the main components that generate power and deliver it to the road surface, water, or air.

Common Causes of P3870

A common cause of code P3870 is the failure of Air Suspension LF Height Sensor Circuit Short To Ground, but there are several other possible causes as well, such as ;

Dirty Oil
Camshaft advance mechanism binding (VCT unit)
Ignition misfiring
Radio frequency interference (RFI)

P3870 code for all cars

You can view according P3870 DTC for your car model. We selected several models to see obd2 solutions click and view it.

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

About Us | Contact | Privacy