7e8 Engine Code Chevy: Causes, Symptoms, and How to Fix

The 7e8 Engine code for Chevy models is set if there is a fuel or air intake systems malfunction. If you are facing low fuel mileage or reduced engine performance, it may be the cause.

You need a proper car diagnosis to determine the root cause of the 7e8 Engine code and fix it as soon as possible. This code will not stop your car from driving but is crucial to solving it before long to enjoy better comfort and gas mileage.

Continue reading for more details about the 7e8 engine code, its causes, and how to fix it. We have presented detailed information about this code in an easy-to-understand manner.

What Does The 7e8 Engine Code Mean?

The 7e8 Engine code represents the vehicle’s engine data stream and shows air pressure loss for the evaporative emission control system. It implies an engine powertrain and should not be confused with the 7e9 code, which means the transmission powertrain.

7e8 Engine Code Chevy

7e8 is a generic engine code that shows a fault in the vehicle’s emission system. The same applies to Chevy cars. It simply means the vehicle is facing fuel or air intake issues. It makes the Check Engine Light come on the dashboard and requires proper diagnosis with a reliable OBD scanning tool.

But you can also diagnose the problem at home if you have a multi-purpose OBD2 scanner. Some OBD2 tools even suggest possible fixes that you can perform in your garage.

Symptoms of The 7e8 Engine Code

The symptoms of the 7e8 engine code are not many. The most obvious one is the Check Engine Light on the dashboard. This is the most misunderstood signal a car gives about a detected problem with the engine because it has a different meaning.

That is why you should scan the stored code to know the severity of the problem and how urgent the fix is needed to save the engine. An OBD2 scanner tool should show the 7e8 engine code in this case.

Another symptom of the 7e8 engine code is the reduced engine performance and low mileage per gallon. You will realize a loss in engine power as the car may struggle to climb under load. That is because of the inappropriate air-fuel ratio in the combustion cylinder. It can be too rich or too lean.

The same applies to mileage per gallon. If the engine does not get enough air for complete fuel combustion, it may use more gas than expected. That will cause a change in smoke from the exhaust, sometimes becoming darker than usual.

Some Chevy owners have reported a revving sound from the engine at idling. An unfamiliar engine sound can also point at the 7e8 code and should never be taken for granted.

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Causes of 7e8 Engine Code 

The 7e8 engine code Chevy can result from a combination of factors. That is why a proper diagnosis is crucial to determine the actual cause before attempting to fix the problem. Consider the following as some of the most common:

01. Faulty Fuel Vapor Lines

As the name suggests, fuel vapor lines return excess fuel to the gas tank for recirculation. They primarily carry fuel vapor from the fuel pump, which it pushes to the gas tank, where they cool and condense as liquid gasoline. 

If fuel vapor lines have a leak, are disconnected, or are unplugged, there will be a significant fuel loss. The engine may be starved of fuel, which triggers the 7e8 engine code. That also results in reduced fuel economy as much of it is lost through the leakages. 

02. Damaged Fuel filler Cap 

Fuel filler cap plays a vital role in the car’s evaporative emission system. It prevents fuel evaporation from the gas tank and entry of water and foreign materials that can contaminate fuel. A fuel filler cap also has a valve for controlling the pressure inside the fuel tank.

Signs of a failing or damaged fuel filler cap include a gasoline smell in the cabin, does not tighten properly, and check engine light coming on. A faulty one allows fuel to evaporate or fails to regulate air pressure inside the fuel tank. These conditions can trigger the 7e8 engine code because of the imbalance brought in by the evaporative emission system. You will also experience poor fuel economy.

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03. Faulty Fuel Canister or Canister Close Valve

The fuel canister is another vital component of the vehicle’s emission control system. It is charcoal-filled to trap fuel vapor that would otherwise disappear into the atmosphere. The trapped fuel vapor goes back to the engine through the purge valve, also known as the canister close valve, and gets burned. That is how fuel canisters control air pollution.

A faulty fuel canister does not perform its purpose as it should. The problem is detected and reported as 7e8 engine code and should be fixed as soon as possible.

04. Faulty FTPS (Fuel Tank Pressure Sensor)

The fuel tank pressure sensor is an integral part of the fuel pump assembly, usually mounted on or inside the tank. It is also a crucial component of an evaporative emissions system that monitors the pressure in the fuel system. It lets the vehicle detect evaporative leaks due to faulty or loose gas caps. 

A faulty fuel tank pressure sensor reports inaccurate or out-of-range data to the control module, interfering with the operation of the EVAP emission system. That triggers the 7e8 engine code.

05. Faulty PCSV (Pressure/Purge Control Solenoid Valve)

The Purge Control Solenoid Valve primarily regulates emissions from your car. It is controlled by a computer algorithm to prevent unburned fuel vapors from venting into the atmosphere when the engine is not running. The captured fuel vapors are temporarily stored in the charcoal canister before they are allowed to flow back into the engine.

A faulty Purge Control Solenoid Valve fails to respond to the control signals, which the system detects as a problem. The control module then activates the 7e8 engine code to alert the driver about the issue.

06. Faulty Seal of the Fuel Pump

The fuel pump seal or gasket prevents the fuel oil leakage onto the cam case. In other words, it makes the fuel pump airtight. If that is not the case, the fuel leaks will cause problems that may starve the engine of fuel to burn. That, too, may trigger the 7e8 code.

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How to Diagnose 7e8 Engine Code

Diagnosing the 7e8 engine code can be time-consuming because of the many possible causes. That is the reason why we recommend taking your car to an auto repair shop if you are not an experienced DIYer.

The diagnosis may involve visual inspection for any leaks from the fuel system or smelling the cabin for any gasoline scents. But the most appropriate approach is using a multi-purpose OBD scanner to read the code and find possible causes or problems to be fixed. This process is straightforward if you have the right scanning tool.

How to Fix 7e8 Engine Code

Fixing this error code involves finding the root cause and taking the appropriate action. It may require replacing or repairing the faulty EVAP control system components mentioned earlier. Consider the following as possible fixes to the 7e8 engine code:

  1. Repair leaking, disconnected, or plug any unplugged fuel vapor lines
  2. Replace missing or damaged fuel filler caps
  3. Repair damaged fuel filler pipe
  4. Repair or replace faulty fuel canister or close valve. 
  5. Replace faulty fuel tank pressure sensor
  6. Repair or replace damaged pressure or purge control solenoid valve
  7. Replace broken fuel pump seals.

But how much does it cost to fix the 7e8 error code?

The figure depends on the car model and the actual component that needs to be repaired or replaced. Typically, you should have about $480-$600 on your budget. Also, remember that the cost can vary significantly depending on the location. Labor charges also differ. So, use the stated figure as a guide but not as the final value.

Alternatively, you can contact a mechanic to give you a more appropriate cost estimate. That should be in line with the current market prices of replacement parts.


Is there any recall/TSB from Jeep?

No. There is no technical service bulletin from Jeep at the moment. There may be one in the future for specific model years if a universal problem is detected that affects safety, emissions, fuel economy, and compliance with regulations and laws. You should check with the manufacturer in the future for any recalls.

Is TSB covered under an extended warranty?

Yes. TSB is a kind of extended warranty since it involves providing repairs during the entire service life of the car. Such repairs cover specific parts, car systems, or identified problems.

Are 7e8 and 7e9 engine codes the same?

No. The two error codes are closely related but are never the same. The 7e8 code is for the engine powertrain, while 7e9 is for the transmission powertrain. Both are not severe but should be addressed as soon as possible.

What is code 07ea?

This code shows a problem with a mass airflow sensor on Chevrolet cars. This sensor measures the amount of air in the engine. If faulty, the code is set, and the Check Engine Light comes on.