B3785 Lexus Daytona Diagnostic Trouble Code

B3785 Lexus Daytona code definition:
B3785 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Lexus Daytona.

B3785 Lexus Daytona 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. If the car doesn't start, they will proceed by testing the voltage at the fuel pump connector and see if the fuel pump relay, fuse, and PCM circuitry should be inspected.

Symptoms

Symptoms of a B3785 Lexus Daytona diagnostic trouble code may include:
  • Faulty PCM
  • The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
  • Poor acceleration
  • If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Place of B3785 in engine

Possible Causes :

  • Fuel with a large percentage of sulfur will clog the DPF quickly
  • The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
  • A large air leak at or near the number one oxygen sensor would also cause a lean mixture.

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 :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code B3785 Lexus Daytona 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 B3785 Lexus Daytona.

Fortunately, B3785 Lexus Daytona is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

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