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How to Check Engine Light Codes Without a Scanner

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Using an OBD1 or OBD2 scanner is something that every car owner should know how to do. 

However, even if you can operate a scanner or code reader, it may not be accessible at all times. That’s why it’s essential to know how to check engine codes without a scanner too.

Fortunately, there are multiple ways to do so with just your odometer or ignition key, which we’ll cover in this article. We’ll show you step-by-step how to check engine light codes without a scanner and answer a few related questions you might have on this subject. 

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Let’s get started.

How To Check Engine Light Codes Without A Scanner (Step-By-Step)

There are multiple ways to access a check engine light code or multiple codes without a scanner or code reader. However, the approach you choose will depend on whether your vehicle generates OBDI or OBDII codes.

Let’s take a look at some methods to obtain your car codes:

A. Using The Ignition Key

The ignition key method is the easiest to obtain OBDI and OBDII codes. 
Here’s a simple step-by-step guide:

Step 1: Turn The Ignition Key

Switch ON and OFF the ignition key without running the engine. Do this multiple times (3-5 times usually) and ensure you stop flipping your key in the ON position. The exact number of times you need to turn your ignition key depends on your car model. 

However, there’s a simple trick. 
Observe the dashboard behind your steering wheel, and if all lights there illuminate, you can stop turning the ignition key.

Note: If you accidentally crank the engine, don’t worry. Just start over, and your car will check for any saved check engine light codes.

Step 2: Check Your Dashboard

Right after the dash lights come up, they’ll turn off, except one—usually the service engine light. 
Now carefully observe it.

If you see the odometer displaying the engine light codes, note down every trouble code (DTC). This method usually works with newer vehicles or vehicles with the OBDII system.

However, if instead of the odometer display, your check engine or service engine light begins to pulse or flash, then your vehicle is OBD1. And the flash created by the engine light is your fault code.

How can you read the code?

Reading a code from a check engine light flash can be tricky. 
Each engine light pulse represents a digit, and the pause between the pulse indicates the separation between the digits. A zero is represented with a quick engine light flash.

For example, vehicle fault Code 32 will go something like this: 
pulse, pulse, pulse, PAUSE, pulse, pulse (3 and 2 = 32).

Step 3: Note And Interpret The Check Engine Codes

Note the check engine light codes as they flash. Then check your repair manual for code descriptions and understand the exact issue.
For example:

  • If you own a Honda, check engine code  0 implies an issue with the Electronic Control Unit (ECU), and code 16 implies problems with fuel injectors.
  • If you own a Nissan, fault code 22 indicates a problem with the fuel pump, and code 31 ECU.

Let’s check out the other method that doesn’t involve an engine code reader or DTC scanner.

B. Using The Odometer

The odometer method lets you read a check engine light code without a scanner or code reader. 
Here are the simple steps to follow:

Step 1: Odometer Reset

Press the odometer’s Trip and Reset buttons while turning the ignition key ON. After turning the key ON, release the odometer Reset and Trip buttons to check if the Diagnostic Trouble Code or DTC appears on the odometer display.

If the fault code shows up, you’ve succeeded in generating a Diagnostic Trouble Code without a code scanner. Note down every fault code and check your manual for the DTC definitions.

Step 2 (Optional): Odometer Reset And Multiple Ignition Key Flips 

In case the reset method doesn’t work, try again. 
This time press the odometer Trip and Reset button and switch the ignition key ON, OFF, and then ON again.

It’s important to end the action in the ON position
Then release the odometer Trip and Reset buttons. 

Check the digital odometer screen; the trouble code should appear.

What if the error codes still don’t appear?
This probably means your car doesn’t support OBDII codes. 
In that case, try Step 3.

Step 3 (Alternative): Use A Paper Clip Or Jumper Wire

If your car supports OBD1 and doesn’t respond to the method mentioned above, there’s another way to get your engine code — using a paper clip or jumper wire.

First, ensure your car is turned off. Then find the OBD port (diagnostic connector) underneath the steering wheel. For the exact location, go through your owner’s manual. You’ll notice two terminals on the diagnostic connector. Connect them with a paperclip or jumper wire. This’ll create a closed circuit. 

Then turn the ignition to ON without cranking your vehicle and the engine light will flash, showing your trouble code. The flash will appear in the same manner as mentioned in the ignition key method — pulses and pauses.

Now that you know how to check engine light codes without a scanner for OBDI and OBDII codes, let’s answer some related questions.

3 FAQs On How To Check Car Codes Without A Code Scanner

Here are some answers to FAQs on reading check engine or car error codes without a scanner or code reader. 

1. How Do I Reset Or Clear Codes Without A Scan Tool?

If you own an OBD1 car, here are the steps on how to reset check engine light codes without using a scanner:

Note: This method works for OBDI vehicles and not for OBDII. To clear OBD2 codes, you need to plug an OBD2 scanner in your 16-pin diagnostic connector. An OBD2 scanner is easily available in the market.

However, no matter the approach, the check engine light will turn on again if you don’t fix the fault code inducing problem.

2. What Should I Know About Checking Car Codes Without A Scanner?

Here are some things to know about checking your car’s error codes:

3. What Is An Odometer Reset Button?

An odometer is an instrument for measuring the distance traveled by your car. And the button used to reset it back to 0 miles is called the odometer reset button.

The button’s location depends on your car model.

For example, if you own a Nissan or Honda, you’ll mostly find the reset button on the left-hand steering wheel lever. Other vehicle models may have it on the dashboard near the odometer.

Final Thoughts

Checking multiple codes without a scanner is possible, and these tips might help you in an emergency. However, checking them without a scanner is not ideal.

Remember, it’s not the easiest to check engine light codes without scan tool handy, especially if your car is OBDII because there are millions of error codes.

That’s why it’s best to employ the expertise of a professional mechanic, like AutoNation Mobile Service.
They’re a mobile auto repair and maintenance solution that’ll help fix all your OBD code issues and even read the error codes if you can’t wrap your head around them.

AutoNation Mobile Service is available 7-days a week, and their online booking makes it easy to get services.

So contact them right away, and their expert technicians will clear codes and stop your illuminated check engine light!