What problems can OBD2 Scanner Detect? - OE Repair Info

What problems can OBD2 Scanner Detect?

OBD vs. OBD2

ODB scanner is an abbreviation for On Board Diagnostics Scanner. An OBD2 Scanner can read trouble codes that trigger the check engine light. OBD2 scanner tools are the latest industry standard and is incredibly more versatile than its predecessor. In 1988 the Society of Automotive Engineers (SAE) set a universal connector plug and a universal set of test signals / trouble codes. Unlike a basic scanner, the OBD2 scanner has a greater ability to define trouble codes and provide more accurate diagnosis, along with being able to tune or tweak performance. In 1996 the OBD2 scanner was implemented and became the industry standard.

ODB2 Scanner Basics

An ODB2 Scanner can detect many things that are going on with your vehicle. It read trouble codes produced by your vehicles onboard computer system. The on board computer system monitors your cars emissions, performance, and numerous other functions. Those codes with trigger and illuminate the check engine light; letting the owner know something is wrong and needs to checked out. The codes produced are 5 characters long. Below is the break down of what each character or digit represents.

First character represents the system related to the problem.

  • B = Body
  • C = Chassis
  • P = Powertrain
  • U = Undefined

The second digit lets you know whether the code is generic or enhanced

  • 0 meaning generic
  • 1 meaning enhanced

The third digit identifies the sub system that the code pertains to.

  • 1 = Emission Management (air or fuel)
  • 2 = Injector Circuit (air or fuel)
  • 3 = Misfire or Ignition
  • 4 = Emission Control
  • 5 = Idle Control & Vehicle Speed
  • 6 = Output Circuit & Computer
  • 7 = Transmission
  • 8 = Transmission
  • 9 = SAE Reserved
  • 0 = SAE Reserved

The forth and fifth digits are variable and related to precise problems.

Example of a Trouble Code

We will use the code P0171 as an example. This code in particular means “System Too Lean” (Bank 1). Possible explanations for this code vary and could mean one or more of the following.

  • The MAF (Mass Air Flow) Sensor is dirty or faulty
    Note: There is an issue in some vehicles, the MAF sensors leak the silicone potting material used to encase the circuitry. Using “oiled” air filters may cause the MAF to become ineffective if the filter is over-saturated.
  • There could be a vacuum leak downstream of the MAF sensor
  • Low fuel pressure (dirty fuel filter/ possible plugged!)
  • Exhaust leak between the first oxygen sensor and engine
  • Possible cracked PCV line or vacuum /connection
  • Plugged or failed/ sticking fuel injector
  • Faulty or stuck open PCV valve Failed or faulty oxygen sensor (sensor 1, bank 1)

Professional Assistance Suggested

As you can see just having the code won’t do a whole lot if you aren’t familiar with auto repair. OBD2 Scanners are very helping with diagnosing a variety of problems. It can also allow you to perform performance tuning. It is a great multi use tool that is imperative to any good auto repair shop. If you have any questions feel free to comment.

Written by OERepairInfo

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