B3790 Alfa Romeo Crosswagon Diagnostic Trouble Code

B3790 Alfa Romeo Crosswagon code definition:
B3790 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Alfa Romeo Crosswagon.

B3790 Alfa Romeo Crosswagon is described as Fuel Rail Pressure Sensor Circuit Malfunction. This code is strictly about the incoming signal from the FRP (fuel rail pressure) sensor falling below the calibrated limit for a certain period of time. Other symptoms that may indicate this problem are when the Check Engine Light illuminates and when there is a visible lack of engine power.

Symptoms

Symptoms of a B3790 Alfa Romeo Crosswagon diagnostic trouble code may include:
  • Faulty or damaged wiring
  • The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly
  • Poor fuel economy
  • If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Place of B3790 in engine

Possible Causes :

  • A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
  • Faulty IMRC actuator relay (if equipped)
  • A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.

Common Misdiagnoses

  1. TP Sensor Learn Not Complete Problem
  2. Low Coolant Circuit Problem
  3. Cruise Control System - Vehicle Accel Too High Problem
  4. TFP Valve Position Switch-Drive Without Drive Ratio Problem
  5. Problem

Repair Processes :

Check to make sure they are not burnt or corroded. If in doubt, get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed. With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground.

Process Tips

Diagnostic trouble code B3790 Alfa Romeo Crosswagon is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before B3790 Alfa Romeo Crosswagon.

Fortunately, B3790 Alfa Romeo Crosswagon is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

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