OBD2 Freeze Frame explained

OBD2 Freeze Frame is a simple but powerful tool when trying to diagnose car malfunctions. Freeze Frame provides insight into the conditions that were present when a malfunction occurred. This post will explain in detail what the Freeze Frame is.

What is Freeze Frame?

In simple terms, a freeze frame is a snapshot of data. It’s a snapshot of sensor or component readings (parameter values) captured at the moment when the electronic control unit detected a malfunction. In addition, the freeze frame contains the Diagnostic Trouble Code (DTC) that the computer system identified as the reason for the malfunction.

OBDII Freeze Frame with the Android app
OBDII Freeze Frame with the Android app

Quite often, the car might have multiple DTCs simultaneously when some fault or faults occur. In this case, you cannot tell what DTC was the first one and caused the Malfunction Indicator Light (MIL) to light. The DTC that’s part of the Freeze Frame will reveal to you the DTC that is the main cause for the problems and occurred first.

The sensor data values stored in the frame help you figure out what might be wrong with your vehicle. However, sometimes coming to conclusions might need some guesswork. Experience with engines and cars will help when analyzing the possible solutions to fix the malfunctions.

For example, when an engine misfire is detected, a snapshot of the current sensor values is captured. The engine control unit stores this snapshot data along with the DTC, and it’s called a freeze frame. The causing DTC might be P0301 Cylinder 1 Misfire Detected, for example.

All OBD2 compliant cars are required to support Freeze Frame. It’s an essential part of onboard diagnostics.

How to read the Freeze Frame?

As the Freeze Frame is an integral part of the OBD2, basically all OBD2 scanners can access and present the snapshot data to you. Reading the Freeze Frame data with OBD Auto Doctor is straightforward. The software fetches the data from the car and gives it to you in a human-readable format.

Whether you are using the computer software or the mobile app, navigate to Trouble Codes -> Freeze Frame.

OBDII Freeze Frame with the macOS software
OBDII Freeze Frame with the macOS software

It’s rather essential to read the Freeze Frame data as soon as it’s stored because most cars can provide only a single Freeze Frame. In some cases, a new Freeze Frame snapshot will override the previously stored data, and you will lose the older data. For instance, an engine misfire will most likely override the previous content. In any case, you should notice that the Freeze Frame is not stored indefinitely.

Can there be multiple freeze frames?

Sure, the OBD2 specification allows the manufacturers to save additional freeze frames. The conditions for storing these extra frames and the content of them are manufacturer-specific.

Is it possible that there’s no freeze frame data stored?

Yes, in some real-world examples, we have seen cases when the Check Engine Light (CEL) was turned on, and OBDII Trouble Code was set without providing a Freeze Frame. The frame was either not stored at all or automatically deleted after multiple successful warm-up cycles. It is not a typical case to happen, but it’s possible.

Is it possible that there’s a Freeze Frame without an Engine Malfunction light?

Yes, in some cases, the car might automatically remove the Engine Malfunction light and the related OBD2 codes. Depending on the severity of the issues, this might happen after multiple warm-up cycles without the problem present. However, the car computer should not clear the Freeze Frame data in this case. Looking at the Freeze Frame snapshot gives you a hint of an intermittent problem.

Can I reset the Freeze Frame?

Yes, you can use OBD Auto Doctor to reset and clear the Freeze Frame. Freeze Frame is removed when you reset the MIL and clear the OBD2 trouble codes. It’s an all-in-one action that resets all the diagnostics data in the car. However, the trouble codes and other data will come back if the problem is detected again.