Guide To P0178 OBD Error Code Solutions

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The P0178 fault code can be defined as fuel composition sensor circuit low input. This fault code would start indicating that the diesel fuel sensor is giving a low input, which could form an open circuit in the sensor or wiring.

The powertrain control module would detect an abnormal voltage reading from the fuel composition sensor or circuit. This sensor is designed in such a way in which it can detect fuel contamination and provide powertrain control module with the right amount of fuel temperature.

What causes this problem with the Fuel Composition Sensor Circuit Low Input?

• The fuel cap might be faulty
• Issue of contamination of fuel
• Defects in the fuel composition sensor
• The connector might be corroded or damaged
• Damaged or restricted fuel line
• Defective or damaged wiring
• There can be some faults in the ECM

1. Flex Fuel Sensor - P0178 code does not really end up spoiling your timing belt, but it might also accompany few Flex Fuel Sensor issues. We have best Flex Fuel Sensor with us
2. Sensor Circuit - There can be some issues with the Sensor Circuit due to which you may see P0178 code appearing over and over again. Visit us to buy best quality Sensor Circuit online.
3. Fuel Delivery System - OBD Code P0178 can appear because of faulty Fuel Delivery System.
4. Fuel Injector Pulse - Defective Fuel Injector Pulse can be a major reason why P0178 code depicts. So, make sure to replace it online so that you don’t have to face any further issues.

You might be thinking that how would you diagnose these problems? We at Parts Avatar Canada would help you diagnose the major symptoms easily.

Common Symptoms

• A rise in the fuel consumption
• Issue of bad performance
• Illumination of the check engine light
• The car engine might start stalling

Learn the ways with which you can correct this trouble code:

• The first and foremost thing which you should do is to drain off the water present in the fuel filter and clear the check engine light codes
• If you find out that there is an open defective sensor, then you must replace it
• An open circuit should be repaired and burned wiring or connection to the sensor
• You can always replace the fuel filter housing with the sensor and then later clear the codes

However, if you face any issue then we have stocked a wide range of best priced mass air flow sensor cleaner, head gasket sealer, blown head gasket and more to help you out in fixing your car.

You can always use a scanner, a digital volt ohm meter, and an oscilloscope will be virtually indispensable for a successful diagnosis of this code setting condition. The fuel composition sensor, or flex fuel sensor as it is called in service part terms, is actually an inline microprocessor that effectively measures the percentage of gasoline that compose the fuel which passes through it route to the fuel rail. The fuel temperature is responsible for measuring with the fuel composition sensor and transmitting this information to the powertrain control module. The fuel composition sensor is a small computer that measures all of the fuel which passes through it to ensure that ethanol, water, and other contaminants do not exceed a certain percentage of the overall fuel makeup. All calculations are made by it concerning fuel composition and temperature and sends an input signal to the powertrain control module. The electrical signal of the fuel composition sensor is seen by the powertrain control module as a square wave form.

The signal varies in frequency according to the degree of contaminants present in the fuel being pumped from the tank to the fuel rail. The pulse width of the square waveform pattern is received by the powertrain control module as fuel temperature. The fuel composition sensor is supplied with a voltage reference which is normally 5-volts by the powertrain control module. It generally has a ground wire and a signal wire. The fuel composition sensor provides ground pulses in direct correlation to the number of contaminants that are present. The typical range of frequency is from 50 to 150 Hertz; with 50 Hertz representing clean fuel and 150 Hertz representing 100-percent ethanol. If there is higher the degree of fuel contamination present, the greater the frequency of the voltage waveform frequency

The fuel temperature is measured by the fuel composition sensor in signal voltage pulse width. The digital pulse width range on most applications is between 1 and 5 milliseconds. Fuel that is at -40-degrees (F) should pulse at increments of 1-millisecond and fuel that is measured at 257-degrees (F) should provide a pulse width of 5-milliseconds. So, the higher the fuel temperature the greater the speed of the pulse width modulation to the powertrain control module

If a voltage reading is detected by the sensor that is not within specs, according to the manufacturer, a code will be stored and a malfunction indicator lamp may be illuminated. Flex fuel vehicles can be operated with a much as 85-percent ethanol as fuel. These types of vehicles are programmed to adjust engine timing and fuel delivery strategy differently than conventional engines. In this type of system, the degree of ethanol present in the fuel is measured as a separate component from another contaminant.

Common Mistakes When Diagnosing The P0178 Code

Follow these guidelines if you want to prevent misdiagnosis:

You must do a visual check of all the connections to the sensor to be sure that they are in good contact. The connection can be loose because someone might have not secured it properly after servicing the filter

P0176 - Fuel Composition Sensor Circuit Malfunction

P0177 - Fuel Composition Sensor Circuit Range/Performance

P0179 - Fuel Composition Sensor Circuit High Input