C3747 Buick Rainier Diagnostic Trouble Code

C3747 Buick Rainier code definition:
C3747 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code for Buick Rainier.

C3747 Buick Rainier 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. The PCM then uses this data to provide the right strategies for the fuel delivery and ignition timing of the engine.

Symptoms

Symptoms of a C3747 Buick Rainier diagnostic trouble code may include:
  • Misfire
  • Misfire
  • The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
  • Diminished fuel efficiency
Place of C3747 in engine

Possible Causes :

  • Faulty IMRC actuator/sensor
  • A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
  • An air leak forward of the DPF will change the sensor readings resulting in the code

Common Misdiagnoses

  1. Crankshaft Position Sensor Circuit Performance Problem
  2. TP Sensor Learn Not Complete Problem
  3. Low Coolant Circuit Problem
  4. Cruise Control System - Vehicle Accel Too High Problem
  5. Kick-Down Switch Failed Short Problem

Repair Processes :

If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code C3747 Buick Rainier 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 C3747 Buick Rainier.

Fortunately, C3747 Buick Rainier is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

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