Simple 3 Step Process of How to Bypass ASD Relay – 2024 Guide

Every auto mechanic should know how to bypass ASD relay because it’s essential. There are several steps you have to follow for bypassing the ASD relay!

To know more about this topic, you have to read this article completely.

ASD or Automatic Shutdown Relay (ASD) controlled all over the power supply modules like ignition coil, fuel pump, and other parts. The main purpose is to shut off the fuel pressure and other ignition systems while you off the car key.

It helps to prevent your car from dieseling, firs, and other types of problems. Now, the Relay is placed in several places on different years.

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Historical Background

From the year 1985 to 1987, the Relay builds the power modules houses within the ASD. In 1985, all the cars that used S-B-E-C or S-M-E-C had an outside relay.

After 1990, the relay box was inbuild within the plastic box at the left side in the car fender well. Whenever you first turned on the ignition, the ASD relay becomes closed.

There are several reasons when the engine become shut down. You have to know the proper ways and steps to follow.

What is the ASD?

ASD Relay

ASD is a very important and common word in automotive industry. If you are in the automobile sector, you should know about this term and its updated styles and process.

While you will work on the engine but the proper signal from ignition is lost, and your car logic module cuts power to the ASD.

It will remove power from the fuel pump, injectors, and ignition coil, and your car engine becomes shut down. While the engine becomes shut down, the logic module in the car maintains the relay driver. If the relay driver is unable to respond properly, then it will trigger a code instantly. 

Assume the key logic module did not provide any sense with an absence of present when the car circuit is available or 11-12 volt DC when the car circuit is stopped. It aware that your circuit is open or close, and remember triggers code is 42.

Later S-B-E-C or S-M-E-C whatever you use, the logic monitors the continuous monitor outcome of the fuel pump in the coach relay result and car fuel injectors.

If you become a failure to start, that means its a failure of automatic engine shutdown, You have to find a proper way to troubleshoot the problem. You have to troubleshoot the problem to start the engine.

Bypassing the ASD Relay, What does it Mean?

If you are facing the engine start problem in the car, you should know how to bypass ASD relay to start the car engine freshly. You have to understand technical mathematics and check every point to understand the car parts’ present situation.

Its engine, fuel parts, and then proceed in every car, power supply done by fuel injectors, fuel pump, and ignition coil and these entire power tools controlled by a logic module, which is called ASD. The main idea behind this is that while the key is off, immediate fuel pressure needs to shut off.

Additionally, during turned the key off, it helps to prevent your car from disabling or fire problems. Now the question is, how do you taste Relay in the car? Well, the answer is very simple.

Why & When it’s Important?

Once you remove the Relay from the car, you have to use an ohmmeter to check its terminal resistance between 85 and 86. Always remember, the resistance should be 5 ohms and 75 ohms. You have to connect two terminals like 30 and 87A with an ohmmeter.

The ohmmeter has to show its ranges 30 to 78A. Another question is how to bypass ASD Relay?Always remember in the car, ASD circuit is completely lame. You have to check whether the battery in the car is draining or not before you jumper the Relay.

There are two pins like #30 and #87 who controlled the power on ASD mode in the car. On to the bypass relay, you have to pins temporarily to put a jumper on it. You have to check all the measures properly before proceeds.

You have to know all the steps on how to relay properly in the car and then proceed. If your car is facing this problem, you may hire a mechanic for this purpose. 

How to Bypass ASD Relay- 3 Step Process

If you want to know how to bypass and relay, then you have to understand the entire process…

First Step– First, you have to open the relay section. Check the first section that is spring. When the car coil is not energized during that time, spring closed the contact.  

Second Step– When the coil of your car becomes energized, you have moveable contact, which you need to pull in. And it also allows current to flow, which helps to set the other contact.  

Third Step- In the below, you will find a path through which current will be allowed and from this position current will flow when the relay coil is not completely energized. You just need to substitute your fuel pump with the fan, and it will work out.

Relay is a very easy and simple device in the car. It is one type of electric switch which you can on and off anytime. In the above, I already stated how to relay circuit work properly. You have to replace the Fan into ASD.

You have to check the bottom or side of the Relay then, And you will find pins. If you check a diagram and check my writing, you will find everything I stated here.

Two pins control the power of ASD that is #30 and #87. You can use those pins and wear a jumper on it to bypass the Relay. If you want to control the circuit or want to make it permanently, you have to install some types of manual switches in the car, which help to on and off circuits.

If you follow the diagram and follow proper steps, you will be able e to bypass the Relay very simply.

Required Tools for the Process

There are different types of tools you may use for this purpose. Some of the important tools are 12 V DC 120 amp 4pin, 40/30 AMP 5 pin SPDT 12 V DC bosch switches, 80/60 AMP waterproof relay, four pins 40/30 AMP 12 VDC harness, etc.

There are different types of tools available online, and if you choose any one tool as per your need and requirement, that will ease your work. As per your car condition, circuit need, and requirement, you can place an order or buy online. You have to check keys, whether they are independent or not.

Also, check the parts or circuit will be able to run with all automotive or not. It simplifies fuel injection testing as well. Always choose a tool made by a reputed tool company. It’s essential to choose the tool which may be fit easily.

You can also check their manuals to know how to use them properly. You can choose any color as per your need and requirement. You may choose black, yellow, red, etc. tool color as per your car and body parts; you may select tools.

Where Will Get this Tools?

There are several online companies’ available reputed eCommerce websites which sell different types of relay products for bypass. You may choose those products and place orders. If you buy from online, you will get an attractive discount on the price that local shops are unable to offer.

Online shops are able to offer you an attractive offer and discount because they don’t have any maintenance costs. You can place an order, and they will deliver the product at your doorstep.

If you do relay bypass through a mechanic, then they will provide you everything. You don’t need to worry. Choose the best tool as per your need and requirement and then place the order online.

Cautions While Bypassing ASD Relay

Its always better to follow the diagram and then check the above-stated steps and follow that. If you follow properly, you will be able to do bypass ASD relay.

But if you don’t understand properly, then it will always be better to consult with the automotive consultant or engineer, and they will check and provide you with complete solutions.


ADS relay has a purpose always. It will not provide power directly to the fuel pump. It will provide power to fuel pump if there is a cam or crankshaft portion sensor that detects at the ECU or PCM; in a single line, it’s unnecessary.

If you thought that Relay is problematic, then you may swap it out using troubleshoot. Many people tried in a different way, like changed fuel pressure, new key switches, sensors, but it did not work properly. You have to trigger the problem properly and then make a solution.

First, you have to draw a diagram, and based on the diagram, and you have to do practical work to get a good result.