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P0169 Wrong Fuel Composition Diagnostic Trouble Code Explained

Filling up a car’s fuel tank with wrong fuel is a common mistake people do on the fuel stations.

According to the research, people repeat this mistake more often on the weekends rather than weekdays.

Also, evening or the midnight is the most dangerous time when people fill up the wrong fuel in their vehicles.

Then the ball comes in the court of the wrong fuel drain companies and mobile workshops. There are hundreds of Diagnostic Trouble Codes (DTC) that actually describe the issue in your vehicle. These codes may vary from make to make and model to model in the cars.

The most widely used OBD2 diagnostic trouble code for wrong fuel composition is P0169.

What is P0169 DTC?

This is a generic OBD2 trouble code for power-train which applies to majority models of Chevrolet, Ford, Toyota and VW vehicles. Apart from these makes it perfectly well fits in GMC, Dodge, and Ram as well.

It doesn’t mean at all that if the code is the same in the above-said makes, the repair procedure will also be the same. The repairs may vary from model to model and make to make in all the above-said vehicles.

How is P0169 Triggered?

This error code – P0169 – is triggered when the Powertrain Control Module (PCM) detects signals from fuel sensors e.g. fuel composition sensor and fuel temperature sensor.

These signals indicate that the fuel delivery is heavily contaminated and has higher levels of ethanol or any other contaminants are mixed in the fuel.

In these conditions, flex fuel vehicles can go even longer even with highly contaminated fuel which has up to 85 percent of mixed fuel.

What is the fuel composition sensor?

It is a small computerized device integrated into the small housing along with the temperature sensor. It works along with the temperature sensor. This small device gives accurate measures of fuel composition to the powertrain control module.

It also analyzes the fuel temperature at the stage when it passes through the inline sensor.

How does it work?

The fuel composition sensor electronically analyzes the data to determine the level of the ethanol and other contaminants in the fuel. It also recognizes the water and other unknown contaminants in the fuel delivery.

Analyzing the composition of the fuel is not the only purpose of this device but it also generates a high voltage string from the car drive-train system. The higher the voltage produced by the device, the higher levels of the contamination present in the fuel.

Apart from other contaminations in the fuel, this system measures the amount of ethanol to exactly deliver the stats.

If the detected amount of the contaminants exceeds the standard limit of that particular fuel ingredient, the PCM system automatically triggers the P0169 and it will appear on the malfunction code list of your vehicle.

This will further illuminate your Malfunction Indicator Light (MIL) on the dashboard of your vehicle which will indicate that you have the wrong fuel injected into the fuel tank of your vehicle.

Wrong Fuel Code Severity and its Symptoms

It doesn’t make any difference that to what extent the code condition is severe. If it triggers, it must be treated according to the procedure. Because it is more crucial to delivering clean fuel which is fit for your vehicle.

So, whenever a diagnose trouble code triggers, it should be taken very seriously, especially, the P0169 code because calculating the fuel delivery strategy is the most critical part of the engine combustion.

Usually, P0169 code doesn’t show any major symptoms but MIL illumination. However, the light can illuminate due to several standards set for the system.

The most major symptoms may include:

  • Abnormal fuel delivery
  • Excessive contamination of ethanol in fuel
  • Wrong fuel used
  • Abnormal fuel temperature
  • Electric system short circuits
  • Damage wiring connectors in the powertrain control module.

It may also illuminate because of a program error in the PCM unit.

In some models, it will also keep ON during the repair process.

Where to start the Wrong Fuel Drain process?

There are two options to start from.

First is to contact your wrong fuel assist service near you and let them do their job as professionals.

Or start from your vehicle technical service bulletins, specifically for your particular vehicle.

It is possible that your issue will be a known issue and a number of fixes will be offered in the bulletins. There is the number of fixes offered for known fixes by the manufacturer which is the best way to save your time and money.

Apart from all these things, during the diagnostic process you need:

  • An OBD2 scanner to scan and diagnose the problem
  • A voltmeter ohmmeter
  • An oscilloscope
  • An infrared thermometer.

It is also necessary to keep the vehicle trouble diagnostic information or any DIY booklet about P0169 trouble code with you to get assistance from.

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Tim MillerFounderOBD Advisor

I knew incidentally what an OBD scanner was by searching on the Internet. Now I have over 10 years of experience in car repair and using OBD scanners. With what I know, I think I should share with everyone. That’s the reason I created this blog.

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