P0093 - OBD Trouble Code

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Is the car’s Check Engine Light On? Is there a sudden drop in the power and acceleration? Are you experiencing reduced fuel economy? All these can be due to problems with the fuel delivery system of the car thus leading to OBD code P0093 getting stored and flashed in the PCM (Powertrain Control Module).

OBD-II Code Decreased engine performance is defined as a Fuel System Leak Detected - Large Leak

The Engine Control Module (ECM) makes use of multiple sensors to ensure that fuel pressure remains constant within the fuel system. If one of the sensors detects a drop-in fuel pressure, the PCM will set code P0093.

To properly meter fuel injection, the Engine Control Module (ECM) closely monitors and modulates the high-pressure system, even between injector pulses. If the ECM detects an unexpected drop in pressure in the high-pressure side of the fuel system, anywhere between the mechanical fuel pump and the fuel injectors, it will set a diagnostic trouble code (DTC), P0093 “Fuel System Leak Detected – Large Leak,” and illuminate the Check Engine Light (CEL).

What causes the problem of Fuel System Leak Detected – Large Leak?

• Failed Fuel injector
• Fuel line common rail leakage
• Fuel pressure sensor malfunction/faulty
• Fuel pump or lift pump failure/damage
• Fuel heater constantly on
• Failed fuel temperature sensor
• Leakage in the high-pressure circuit
• Electrical connector corrosion/damages
• Fuel pressure regulator malfunction/faulty
• Plugged fuel filter dropping the fuel line volume
• Injector pump leakage
• Fuel control actuator failure/faulty
• Cascade overflow valve malfunction/failure
• Electrical harness damaged at the injectors or to the ECM
• Fuel pressure valve limiting
• ECM failure/faulty

1. Fuel Pump - Check for failure/damaged fuel pump for the reason of drop in the fuel pressure. Replace faulty pumps immediately.
2. Fuel Pressure Sensor - Faulty sensors can cause error in estimating the fuel pressure as the data sent to the ECU can be faulty, leading to performance issues. Replace them now!
3. Fuel Pressure Regulator - The right amount of fuel pressure the important for the internal combustion system to function at maximum capacity. Thus, replace faulty regulators immediately.
4. Fuel Injection - If the fuel injection is faulty, it will lead to malfunctioned fuel delivery system due to loss of fuel pressure entering the engine. Replace faulty systems now!
5. Electronic Control Unit - Faulty ECU can lead to problems with the fuel delivery system. Replace it now!
6. Diagnostic Tools - An experienced mechanic will make use of factory grade tools to diagnose an OBD problem. Buy best tools and equipment from us.

Some of the dramatic symptoms for this code may include smoke from the engine area, reduced acceleration, the engine may be disabled, and the strong odour of fuel may be present as well.

Common Symptoms

• Increased fuel consumption
• Extremely poor fuel economy
• Burning smell for under the hood
• Decreased Fuel pressure (could cause the engine to run poorly, further decreasing fuel economy)

Any part of the fuel system can cause this code. Some of the parts that could be replaced to repair this issue would include:

• Fuel tank
• Fuel lines
• Fuel hoses
• Fuel injectors
• Fuel rail
• Fuel pressure regulator

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• Take the help of an experienced mechanic who will visually inspecting the fuel system, searching primarily for the leak. Since the leak is considered a large leak, it should be fairly easy to locate.
• The mechanic will repair or replace the part that is causing the large fuel leak, once the source of fuel leak has been found.
• Check for any wiring and harness issues and correct the damaged wirings.
• If there is no leakage found, check for the faulty ECU. Although, this fault is very rare but can be a reason for problematic fuel delivery system, thus hampering the engine performance. The ECU needs to be replaced in such condition and has to be reprogrammed to erase any stored faulty error.

Common Mistakes When Diagnosing The P0093 Code

• Considering that the issue at hand is a large fuel leak, it would be quite difficult to make a mistake during diagnosis. This issue is as simple as locating the fuel leak and having it repaired.
• Check for the error code indicative in the PCM to avoid any rushed entrance in the system and analyse the problem properly.
• Always use the components as per the specific make and model and manufacturer’s specifications to avoid any future leakages.

P0094 - Fuel System Small Leak Detected