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Home: FAQ: Automotive Diagnostic Tools - Questions about Readers & Scanners

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You're driving along, and that little light on your dash comes on. What do you do? The "check engine" light can mean many different things, from a loose gas cap to a seriously misfiring engine. Your vehicle's computer has detected a problem and it stores a "trouble code" in its memory that identifies the source of the problem.

With your own diagnostic scan tool, you can connect to your vehicle to read that trouble code. This is the first step in diagnosing the problem.

What is the difference between a Reader and a Scanner? Readers and Scanners both display vehicle computer fault codes with descriptions. Scanners have the additional function of providing real-time component voltage and current outputs. Some examples of these components are: 02 Sensors, Fuel Injectors, Throttle Position Sensors, and Transmission Sensors. An example of a Code Readers is the Actron CP9125 PocketScan.

What is the difference between OBD I & OBD II (On-Board Diagnostic I & II)? OBD I refers to most domestic cars manufactured 1981 1995. Before OBD II was enforced, manufacturers used different data link connectors to communicate with the vehicles.

OBD II covers all passenger cars and light trucks built for sale in the U.S. 1996-present. Any vehicle with a GVW (Gross Vehicle Weight) up to 8,500 has to be OBDII Compliant (California GVW 1400). Any vehicle over the GVW of 8,500 (i.e. Medium/Heavy Duty trucks) may not be compliant - This information can be found on a sticker located on the driver's doorframe.

What are generic or global OBD II codes? Generic or global OBD II Diagnostic Trouble Codes are common for any OBD II compliant vehicle, be it Domestic, Asian or European. These codes are sometimes called "P-codes" and typically begin with "P0" or "P2".

What are enhanced or manufacturer specific OBD II codes? Enhanced or manufacturer OBD II Diagnostic Trouble Codes are unique to a vehicle of a specific year, make, model (and possibly engine size). They are assigned by the vehicle manufacturers to cover situations not already covered by a Generic DTC. These codes typically begin with "P1".

Will these Code Scanners and/or Scan Tools retrieve Anti-Lock Brake or Airbag codes? OTC Products such as the Nemisys and Genisys can be used to retrieve these codes. However, most do-it-yourself level tools retrieve Diagnostic Trouble Codes (DTCs) from the Powertrain controller (engine computer) only. Some exceptions are the OTC3111 and the Actron CP9580, which have ABS code read/erase capability for most 1996 and newer GM, Ford and Chrysler vehicles. The Actron CP9449 is specifically an ABS tool and is compatible with most OBDII domestic vehicles 1996 - 2005.

What about Diesel Engines? Actron tools will do well with the Chrysler and GM Diesel vehicles that are OBDII compliant. There are some issues with the Ford diesels, especially the F-250's and up. AutoXray tools do not do well with diesels of any sort except the smaller import vehicle diesel engines (i.e. VW).

Most of the do-it-yourself level scanners will not connect to Chevy Duramax and Ford Powerstroke diesel vehicles because their GVW exceeds the maximum requirements of the OBDII standard. Since these trucks are not officially OBDII compliant, most scanners will only give you a very limited amount of data. If you have one of these trucks, we recommend either the OTC3499N tool or the AutoEnginuity scanner with the appropriate enhanced software package.

I seem to have an oddball OBD-I vehicle. Help! Do you have a 1994 or 1995 GM or Ford vehicle that has the 16-pin OBD-II connector but still uses the OBD-I Engine Control Module? Then click: AutoXray Special Blue Cable.

Do you have an OBD-I Ford Aspire, Festive, Escort, Probe or Mercury Capri or Tracer? You may need: Ford MECS cable.

Do you have a 1993, '94 or '95 Chrysler Concorde, Intrepid, Vision, LHS or New Yorker? You may need: Chrysler LH cable.

If you have questions that are not answered here, please call us at (866) 553-8116.

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Keywords: automotive, diagnositic, tools, tool, scanner, reader, actron, autoxray, otc, obd, I, II,