Rick's Free Auto Repair Advice

Best OBDII Scanner

What to look for in a smartphone or laptop OBDII scanner

You can buy a handheld OBDII Scanner, but the trend in diagnostics is towards using a smartphone app and a Bluetooth OBDII interface that connects to the diagnostic link connector (DLC) under your dash.

How to buy an OBDII Scanner App

First, look before you leap. Check out each OBDII scanner app to make sure it works with your vehicle and provides all the data you need to diagnose your car. Here’s what you need to know:

Does the OBDII scanner read both Generic and Enhanced trouble codes?

All inexpensive apps read generic powertrain (P)

Blue driver OBDII scanner

Blue driver OBDII scanner

trouble codes. But more and more car makers are using “enhanced” or “model specific” trouble codes. Scanner software that reads enhanced codes costs more because the app writer has to pay for that information.

What happens if your app doesn’t have enhanced code capabilities? You may find yourself in a situation where you have a check engine light, but your OBDII scan tool comes up with no codes. How can that be? I mean, if a check engine light is on, a code IS stored. But if your OBDII scanner can’t read the enhanced code, it will come up blank. Trust me, you want an app that reads enhanced trouble codes.

What is an enhanced trouble code?

The OBDII rules require all Generic P trouble codes to start with P0100 and go to P0900. The codes must mean the same thing across all makes and models. So a P0128 means the same thing no matter the year, make, or model you’re working on.

Enhanced codes are different. They start at P1000 and go to P2999. These codes allow the car makers to make up their own definitions and those definitions can vary by year, make and model. So a P1192 on one vehicle can mean something different on a different brand. The car makers are NOT required to give away enhanced trouble code information for free, like the generic trouble codes. So the software needed to read and decipher enhanced codes will cost more.

Does the OBDII scanner read B, C and U trouble codes

In addition to enhanced codes, your OBDII scanner tool should also be able to read Body (B), Chassis (C) and Network (U) codes.

Does the OBDII scanner app provide record and freeze frame capabilities?

Freeze frame is a must if you need to track down an intermittent problem. It works by recording 30-seconds worth of data before and after you press the record button. So you can take your vehicle for a test drive and hit the record button the instant you encounter the problem. Then return home and read the freeze frame data.

Does the OBDII scanner tell you if the readiness monitors are set?

You can’t get smog or emissions testing if all the readiness monitors aren’t set.

Does the OBDII scanner give you access to all the parameter I.D.s (PIDs) you need?

Not all scanners read data from all sensors.

How much does the recommended OBDII scanner interface cost and is the firmware upgradable?

The interface plugs into the diagnostic link connector (DLC) on your vehicle and communicates with your smarthphone or laptop through Bluetooth or WiFi. The best units are firmware up gradable, but they cost more.

©, 2019 Rick Muscoplat

Posted on by Rick Muscoplat

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