B3521 Daewoo No 1 Diagnostic Trouble Code

B3521 Daewoo No 1 code definition:
B3521 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Daewoo No 1.

B3521 Daewoo No 1 is described as Oxygen Sensor Circuit No Activity Detected (Bank 1, Sensor 1). This means there's a problem in the front oxygen sensor on Bank 1, as the O2 sensor is inactive. 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 B3521 Daewoo No 1 diagnostic trouble code may include:
Place of B3521 in engine

Possible Causes :

  • Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
  • Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
  • Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

Common Misdiagnoses

  1. Vehicle Speed Output Circuit Problem
  2. Cruise Control Servo Indicates Low Problem
  3. A/C System High Pressure High Temperature Problem
  4. PCM Stack Overrun Problem
  5. Transmission Control Module Reprogrammable Memory Problem

Repair Processes :

Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness. If you find a related TSB, the information will often help in diagnosing the code in question as TSBs are crested from many thousands of repairs.

Process Tips

Diagnostic trouble code B3521 Daewoo No 1 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 B3521 Daewoo No 1.

Fortunately, B3521 Daewoo No 1 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

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