Introduction: DIY: Reset Airbag Computer Crash Data

When a vehicle is rebuilt after a collision involving airbag
deployment, the airbag computer must be replaced. Here’s a video on how to clear the crash data from the airbag computer and reprogram it with clean virgin data.

Step 1: Introduction

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The airbag computer controls the supplemental restraint
system in your vehicle, including the airbag sensors, inflators and seat belt pretensioners. It also acts as a black box when you get into a major collision that involved airbag deployment.

Let’s say you get into a collision with your beige Corolla.

And your airbags deploy:

Step 2: Airbag Computer's Cannot Be Reused

Picture of Airbag Computer's Cannot Be Reused

Well if you decide to rebuild the vehicle and replace the airbags:

You need to replace the SRS computer, since it has a hard
code inside that can’t be erased and you’ll be stuck with an airbag light on:

You won’t even be able to access the SRS computer using
Toyota’s techstream software either:

Step 3: Remove the Airbag Computer

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The airbag computer is located underneath the dashboard. The
bottom half needs to be removed to access it.

Disconnect
battery before working on SRS system:

Step 4: Disasemble the Airbag Computer

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Airbag computer removed:

Open up the computer:

We’re looking for this 8 pin SMD EEPROM chip here that stores the crash data, it says L56R on it:

Step 5: Solder and Hookup to an EEPROM Reader

Picture of Solder and Hookup to an EEPROM Reader

Solder some 32 gauge hookup wire to connect it to the serial
port EEPROM reader:

I built a little EEPROM reader using some resistors and diodes:

Here’s the setup, with the airbag computer EEPROM going to
the reader, and then the reader going to the serial port directly on a legacy Pentium 4 computer. You can also purchase USB EEPROM readers:

Step 6: Analyze Crash Data

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Then I used PonyProg software which is a serial device
programmer to read from the EEPROM chip:

Here’s what the crash data looks like:

From a clean, uncrashed Corolla, I dumped the information
from its SRS computer and it looks like this:

Comparing the two, you can see a lot of data values have
changed.

So now I’m going to replace all the values from the crashed chip with those from the virgin chip and rewrite it to the computer to clear the hard code. Then I’ll replace it into the vehicle:

Step 7: Replace the Airbag Computer

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So now I’m going to replace all the values from the crashed chip with those from the virgin chip and rewrite it to the computer to clear the hard code. Then I’ll replace it into the vehicle:

Step 8: Test to Make Sure It Works

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The SRS light should go out within 6 seconds if everything
is functioning normally. I also double checked it with Toyota’s techstream software and there aren’t any codes or faults found.

And It works!

Comments

liquidhandwash (author)2017-05-01

Thanks that is good info. The duck was a nice touch. :-0

How long did it take you to find out it was that eprom that was the problem?

speedkar9 (author)liquidhandwash2017-05-01

Thanks! You made it to the end of the video haha.

I did some research and found that there are services out there that clear the info from the SRS computer. I have previous experience working with EEPROM's so as soon as I opened up that motherboard I knew where to head.

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