In the past, the best ways to figure out problems with the fuel pumps were by analog and hands-on means. As time evolves, the fuel pump-related problems can be diagnosed using a pressure gauge and voltmeter.

In the context of used cars Calgary, where the automotive landscape may include a mix of older and more recent models, understanding and utilizing advanced diagnostic tools becomes crucial. Whether dealing with vintage vehicles or more recent acquisitions, the scan tool provides a comprehensive approach to identifying and rectifying fuel pump issues, ensuring optimal performance and reliability.

The best tool available for figuring out a fuel supply issue is the scan tool. The old cars were easily invigorated by a simple turn of the key. This ensures that the vacuum-operated diaphragm controls the car’s fuel pressure.

Unfortunately, this method no longer works for modern cars. That is because they involve at least two modules and various sensors. They are all linked on a high-speed serial data bus to operate a fuel pump. Unlike what you would think, this does not complicate the diagnostic process. It rather simplifies it and saves unnecessary fuel drop.


For the car’s fuel system to function optimally, at least four significant parts come to play. These components are the fuel pump, fuel pressure sensor, fuel rail, and ECU. If the fuel pressure does not reach the level required by the manufacturer, the car will likely not respond. This makes it very important to check the fuel pressure of the car before setting off. When the fuel pressure is low, the car begins to ‘act up,’ and you begin to notice new signs with the car. This often results in an inconvenience at least and a huge headache at worst. What are the symptoms, you may ask?

One of such signs is an unresponsive throttle. For cars to function correctly, there needs to be appropriate fuel delivery to the cylinders. With a low fuel pressure, the cylinders do not receive as much fuel as they require, so they begin to act up. You then notice lags which indicates that something is wrong with the fuel pressure.

One of the reasons why you find it challenging to start your car is low fuel pressure. For the car to start, it needs a lot of fuel but is not getting it due to faulty or low fuel pressure. Should you notice that it takes you longer to start your car, you should look at the fuel pressure. Spluttering and stuttering sound when you try to start your car is also an indication to check out your fuel pressure.

A stalled engine is a clear sign that you need to check out the fuel pressure. Should the engine stall either when the car is running or idle, then the fuel pressure is low or fluctuating? Low fuel pressure can also turn on the “check engine” light of your car.


Before we talk about how to check fuel pressure with a scan tool, let us first discuss what a scan tool is. A scan tool is an electronic device that is used to interface with, diagnose and occasionally reprogram a car’s control modules. As an essential diagnostic tool for cars, scan tools have a wide range of features. Their features include a code reader, the capability to view and sort live data and check fuel pressure. As scan tools are designed to talk to the car practically, it is a pretty handy tool when trying to figure out what is wrong with your vehicle. A scan tool allows you to confirm if the modules which control the fuel pump are getting the correct instructions.

A step-by-step process of how to check the fuel pressure with a scan tool is:

STEP 1: Try To Start the Car for A While.

Before checking the fuel pressure, starting up the car for a little while warming up the engine, is a significant step. This is because cold engines can alter the fuel pressure readings if there is indeed a problem with the fuel pressure. It is wiser to start the car engine and possibly take the car out for a ten-minute drive to warm up the engine.

STEP 2: Link the Diagnostic OBD-II Scanner to the Car.

Should you decide to go for a scanner with a wire, the first thing to do is find a plug for the OBD-II in the car. The socket is then connected with the wired scanner before kicking off the engine. You can find the socket just beneath the dashboard, possibly hidden under the plastic trim. The wireless scanners often connect with an app that is available on smartphones and tablets. To join, you connect the OBD-II device and loop in with the app.

STEP 3: Look Out for Saved OBD-II Error Codes

To save time, it is best you first check if there are saved error codes. Any issue with the engine’s fuel delivery might have been noted in the ECU memory as an error code. Some of the well-known OBD-II error codes that are stored in association with fuel system problems include:

  • Error Code P0203: This code is defined as the Cylinder 3 Injector Circuit Malfunction. The presence of this code indicates that the ECM has noticed a problem with the injector. It is also indicative of a problem in the injector circuit for Cylinder 3.
  • Error Code P0170: This code is defined as the Fuel Trim Malfunction (Bank 1). Its presence indicates a problem with the fuel trim being outside the range specified by the manufacturer. This outside range detection can be in the positive or negative sense.
  • Error Code P0171: This code is defined as the System Too Lean Bank 1. This code appears when there is too much oxygen in the exhaust. The oxygen sensor detects this problem in Bank 1.
  • Error Code P0191: This code is defined as the Fuel Rail Pressure Sensor Circuit Range. This error code arises when inconsistent readings are coming from the fuel rail pressure sensor. It often appears with the error codes P0171 and P0172.
  • Error Code P0172: This code arises when there is too much gasoline, so much so that it reaches the injectors. This code appears when there is too much gasoline such that the ECU cannot adjust to it. It showed that there isn’t enough oxygen in the air-fuel ratio.

STEP 4: Review the Live Fuel Pressure Data.

If there are no obvious problems that are recorded in the storied error codes, the next thing to do is check out the fuel delivery system. This analysis is done by gauging the fuel pressure and the fuel delivery rate. To get the right results, you need the OBD-II code reader to gauge the real-time engine data. You then connect the diagnostic reader to the car and read the engine parameters. When that is done, select the fuel delivery system option. This allows you access to monitor the different fuel system parameters like the fuel rail pressure, among others.

You can accurately measure the actual fuel pressure of the car while the engine is still running. All you have to do is pick the choice closest to the ‘certain fuel pressure parameter’ on the menu. This will lead to a display of the fuel pressure of the car currently. You can rev the car engine to at least 1500 rpm, hold it for a couple of seconds, and then revise it again at 2500 or 3000 rpm. This will let you know if the current fuel pressure remains constant under load.


Understanding the importance of fuel pressure is very important. Knowing how to check the fuel pressure correctly will significantly cut your workload in half and make you more valuable. By using a scan tool, you can get a lot of diagnostic processes done with ease in the driver’s seat of your client’s car. This would efficiently increase your productivity and improve your accuracy. This translates into a productive and profitable workplace with a reputable name and reduced wasted effort.

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