This article will show you how to see the failure information of your car without using any special tools.


What is OBD?

OBD stands for On-Board Diagnostics.

OBD1 was introduced in 1988 by the California Air Resources Board.

The second version, OBD2, was introduced in 1994.
OBD2 was instituted to prevent increased harmful exhaust emissions when a vehicle malfunctions.
OBD2 can monitor systems related to exhaust emissions.

What is a DTC (Failure Code)?

Failure codes are called DTCs (Diagnostic Trouble Codes), consisting of a single letter of the alphabet and a four-digit number.
The alphabet represents the following.

B: Body Body electrical system
C: Chassis Chassis
P: Power Train Power train
U: Network

How to view DTCs (Failure Codes)

To view a DTC, short a specific terminal on the OBD coupler and start the engine.

The terminal to be shorted differs depending on the manufacturer.
The positions of the terminals to be shorted in major manufacturers are as follows.

Toyota: 4 and 13
Nissan: 1 and 8
Honda: 4 and 9

I own a Honda HR-V, so I shorted the terminals 4 and 9.

How I did it

Where is OBD location?

The Coupler I used

I use the following coupler to short-circuit the terminals.
Since the position corresponds to the red-framed position in the above photo, the male terminal is in the yellow-framed place below.

I short-circuit using an alligator, as shown below.

I use the coupler as shown above to short-circuit for safety, but it is also possible to short-circuit by directly inserting the terminal into the car’s DTC coupler.

Please be careful not to short to an unintended location when doing this.

Displaying Fault Codes

I will practice how to display the fault codes.
With the engine off, short-circuit terminals 4 and 9, then start the engine.
Then, as shown below, I displayed the failure code U1280 on the meter.

If more than one DTC (fault code) is displayed, you can check the other fault codes by pressing the switch that looks like a stick attached to the meter.

In my case, only the U1280 failure code was displayed.

How to check the contents of the failure code

I mentioned that U is a network system failure, but I do not know what it is in this state.
You can find out what it is by using the DTC Decode site.
U1280 seems to be a DTC (failure code) indicating a communication line error.

Communication Bus Line Error (BUS-OFF)

DTC Decode

Since no problem is observed in the current operation, it is presumed that this was probably a temporary occurrence.


I displayed a DTC (Failure Code) by shorting a specific terminal on the OBD coupler and starting the engine.
The contents of the failure code can be checked at the DTC Decode website.
Why don’t you look at your car and see if there is anything wrong with it?

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Author of this article

I am an engineer working for an automotive company in Japan.


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