How Do You Fix OBD Communication Failure? (Step By Step)

Suppose you inserted an OBD2 scan tool in your vehicle, but it doesn’t connect with your device. Sometimes, it happens due to OBD communication failure.

If your OBD is also not responding/connecting, you can try these tips to solve the issue.

In this guide, we will learn the reasons for unresponsive OBD and how to fix the OBD communication failure issue step by step.

Why is OBD Not Communicating With ECU?

OBD Communication Failure

If your OBD2 scanner is not communicating to ECU doesn’t mean the OBD2 scanner is defective.

I do not deny that the faulty OBD2 scan tool could not be a reason. It’s possible because you received a faulty unit, but there are many other reasons people face communication failure with ECU.

Following are the common reasons why OBD2 does not communicate with ECU-

  1. Blown power fuse in the fuse box.
  2. Dirty/rusty OBD2 port.
  3. Broken OBD power wire.
  4. Bended OBD2 scanner pins.
  5. Problems in ECU.

These are the common reasons why you’re facing communication failure with an OBD2 scanner. However, if you’re using a Bluetooth OBD2 scanner, then the problem could be App firmware.

How To Fix OBD Communication Failure?

If your OBD2 scanner is not communicating, you can try these solutions to fix the issue:

1. Check Fuse Box

Car Fuse Box

Your vehicle’s ECU needs the power to function properly. It receives power from your car/truck battery which is connected via a fuse. The fuse is used to prevent the parts damaged due to a sudden hike in voltage.

If you’ve plugged the OBD2 scanner in the OBD port, but the device is unable to communicate with ECU, then your ECU (computer) may be turned off because the connecting fuse is blown.

You can detect the issue by turning on your ignition. If you turn on the ignition and MIL (malfunction indicator lamp) or Check Engine light is glowing, it means your ECU is receiving the power.

You can also verify the issue by opening your fuse box and checking if any fuse is blown. If blown, insert a new fuse box of the same ampere rating.

2. Clean The OBD2 Port

OBD2 port cleaning

The dirty OBD2 port is the second reason why your OBD2 scanner not communicating with ECU. First, remove the cover from the OBD2 port and check if any dust is stuck in the port.

If you find your OBD2 ports dirty, clean with the help of a brush and remove any foreign material stuck in the pins with the help of a needle.

3. Broken OBD Power Wire

Broken OBD2 Wire

Some car owners reported that their OBD2 powering wire was broken or damaged by rats.

You can take the OBD2 port out of the dashboard and ensure that the wire that powers the OBD port is not damaged or broken.

If you found that the wire that powers the OBD2 port is broken, take your car to a certified mechanic or brand service center and get it replaced.

4. Damaged OBD2 Scanner Pins

Damaged OBD Adapter

If your OBD2 adapter is not working, then remove it from the port and check if any pin on the scanner is not damaged or bent.

If you found any broken or bent pin in your adapter, replace it immediately.

5. Update OBD App

FIXD Update

Bluetooth OBD2 scanners are very popular nowadays. FIXD and BlueDriver are the two most popular wireless OBD2 scanner that connects with Android and iPhone via Bluetooth.

If you’re using any Bluetooth OBD scanner, then make sure you have installed the latest version of the recommended app by the scanner brand. You can update your OBD app and firmware from the app dashboard itself.

6. Get Your ECU Reprogrammed

If you tried all the solutions mentioned above, but the problem is not fixed yet, then there could be something wrong with your ECU. Take your car to a certified mechanic or car brand’s service center to get your ECU reprogrammed.

Conclusion

Thousands of car owners reported the OBD communication failure issues. I’ve explained the top 5 reasons why your OBD2 is not communicating with ECU.

You can follow the above steps to fix the issue. Take your car to a certified mechanic shop or brand service center if you cannot figure it out.

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Hi, I'm Richard, an ASE-certified mechanic in Florida, USA. I love to optimize car ECU for better fuel economy and troubleshoot engine code errors and fix them.

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