Why Is Your OBD2 Scanner Not Communicating?

Working with OBD diagnostic tools is considered to be a pretty straightforward task. However, in some rare cases, the communication and connection to the system can become troublesome, showing the ‘No-Communication’ error. You’ve probably tried to contact the tool supplier; however, if you haven’t, keep on reading.

We do understand; this issue is quite common while using a diagnostic tool. Thus, in this article, we will explain some of the reasons and solutions for these errors.

OBD Diagnostic Tools is Not Compatible With Vehicle

A usual issue with the communication arises when you try to connect the tool with a non-standardized OBD protocol, for instance, ALDL, MUTT, or OBD1. These specific protocols need a tool with software designed for their PIDs. For good practice, find a multi-system diagnostic scanner like from Core Diagnostics that has both OBD I&II compatibility. 

Ignition Key Is Not at A Run Position 

The car diagnostic scanners require the vehicle’s engine or the ignition to be running. So, make sure not to miss this step. Remember, many automobiles need some seconds to activate all the modules to complete the boot-up sequence. A good practice is to connect your scanner after all the dashboard activities are completed. Or else, if the system boot-up is not finished, the tool will not show any readings.

Blocked Port

Another reason for getting a ‘No Communication’ error is the scan port has been clogged up with dust. It would help if you didn’t use spray or anything that could get the port wet. Instead, wipe it with a soft cloth or blow compressed air through it. It will clear up all the things that could get in the way of the scanner to give a good reading. 

Low Or No Voltage on The Connector

Based on general specifications, the connector should have 12-v power on pin 16 and ground on pins 14 & 15. The scan tool requires this voltage to work efficiently after the ignition key has been turned on. If the pins between car diagnostic scanners show no reading, then a blown fuse is likely to be a problem, which we will discuss later.

Hung Up ECM Communications

Now and then, the ECM can get stuck in the ‘hung up’ mode. It can perform some functions; however, the scan tool will not establish the communication link with the vehicle. If all other checks are verified, then ECM may need to be rebooted. To do so, disconnect the battery leads, and press the brake pedals. All the capacitors in the system will be discharged. After this, when you reconnect the battery, ECM should be able to display the readings now. 

Before disconnecting the battery, turn to the vehicle’s owner manual for the proper procedure.

Blown Fuse in The Vehicle Diagnostic Tool

If you are unable to get reading from the tool, don’t declare it dead yet. The most common reason for this is usually a blowout fuse. With no power, the electronic control module (ECM) won’t display the codes. Make sure to check your fuses to see if they work correctly. Sometimes, even the fuse dedicated only to OBD diagnostic tools can blow up for no apparent reason. So, look out for that.

Invalid or Missing Data 

When the OBD diagnostic tool is connected to a vehicle, it asks the ECM to provide relevant PIDs. Some tools consider the last car attached as a new vehicle as well. So, when it evaluates data, some of the PIDs may be shown as missing or unavailable. 

To overcome this issue, the diagnostic machine scanner will allow you to query for the PIDs. It can take a minute or two, depending on the vehicle. Once this process is completed, the list of PIDs should now match the car and provide accurate data. Remember, not every tool automatically scans the PIDs; they rely on the vehicle’s VIN to check the valid data.

It is good to scan the PIDs to ensure the scan tool report is similar to what ECM provides. It is a helpful thing to do as it makes sure your equipment has accurate data.

Final Thoughts

The points above reveal the reasons OBD diagnostic tool isn’t communicating the codes. However, the problems aren’t confined to it. This is why choosing the right diagnostic tool supplier is essential. They can help in the future with troubleshooting requirements. We hope you found this guide useful to overcome the issues.

Image used: Photo by Andrea Piacquadio from Pexels