• Troy Wierenga

Meet Mr. OBDII Freeze Frame...

Updated: Jan 22, 2018

Mr. Freeze Frame was witness to a terrible crime. The victim, Mr. Engine, an innocent

OBDII compatible vehicle that was assaulted by some jerk, AKA Root Cause. This jerk

wore a mask and only left a note. (Diagnostic trouble code) Unfortunately Mr. Freeze Frame was just riding along with Mr. Engine when all this happened, and he did not get a good look at the suspect.

You are the detective. This check engine light may or may not become a tough case for you to solve. Don’t waste too much time with Mr. Freeze Frame. He can answer the following questions and no more.

  1. Was it cold, warming up, or hot? (Engine coolant temperature, Intake air temperature)

  2. Where you accelerating, decelerating, cruising, or idling? (RPM, Throttle position, Manifold air pressure, Mass air flow).

  3. How fast were you going? (Vehicle speed).

  4. How long were you driving before the code was set? (Engine run time).

Write down his answers, then go and record some live data. If you pay close attention to the conditions Mr. Freeze Frame told you about, you have increased the probability that you will find the next clue.

Keep in mind:

Some manufacturers store their own freeze frame for any and every code that is stored. The high dollar scan tools have also paid the manufacturers fees for access to that information. But when using generic OBDII, it only stores 1 at a time. It seems unfair, I know. It's just what comes with a low price tag. Just remember that if you have 3 codes stored, your ECU will pick which one it thinks is affecting emissions the most, give you the freeze frame for it, then throws all the others away. No recycle bin or trash folder to go to. If you decide to press the clear codes button, Mr. Freeze frames statement will also be gone forever.

If the car is running bad all of the time, forget Mr. Freeze Frame all together and get your mind in a 'back to basics' mode. Freeze frame is most important when there aren’t any noticeable symptoms, or the problem is intermittent. Why spend precious time reading through warm cruise PID data, if the code was set during cold idle?

The take away…

Life is short, don’t waste it trying to diagnose your car with freeze frame data. Freeze frame is just a small clue. One that is meant to help you with the first stage of any drivability diagnosis, and that is duplicating the problem.