U3870 Volkswagen Auto Trouble Code

U3870 Volkswagen Auto Trouble Code on vehicles with electronically controlled automatic transmissions, the 3-4 shift solenoid is responsible for actuating the hydraulic circuits to activate clutches or bands that change gears inside the automatic transmission.

The crank but won't start condition, along with the trouble codes may make you think you've got a PATS anti-theft system problem. However, Ford reports that these codes are all related to software bugs. The only way around the problem is to reprogram the PCM with the latest software.

U3870 Volkswagen Possible Solution:

Excessive air inflow can be caused by a vacuum leak, a dirty sensor or, an exhaust gas recirculation valve not closing properly. If the problem is not enough fuel, the culprit may be dirty injectors or fuel filters, a weak fuel pump or a leaky fuel pressure regulator. The lean fuel mix error may be accompanied by rough idling, engine misfires, hesitation during acceleration and overall poor engine performance.

U3870 Volkswagen Description For All Models :

U3870 Volkswagen Trouble Repair :

The sensors receive a 5 volt reference signal from the PCM. As pressure readings change, the sensor varies the voltage and the computer reads that to determine input. In the case of a broken wire, the sensor never sees the voltage and the computer assumes a major fault. So if you get this U3870 Volkswagen code, first check to make sure you're getting a good 5 volt reference signal at the sensor.

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