Being able to warm up or cool down the car before getting in is great. But what if you try pressing the remote start one day, and nothing is happening? I know the frustration, and I have a way to fix it.
What causes the remote start not working – check engine light on? Typically, this happens due to a safety feature that can be triggered by either of the following problems:
- Loose, cracked, or missing gas cap.
- Oxygen sensor issues.
- Catalytic converter failure.
- Mass airflow sensor failure.
So, you need to troubleshoot what caused the engine check light to illuminate to get the remote to start functioning again. I have explained this in depth below.
What Are The Common Causes Of Check Engine Light On?
Whenever you see the check engine light illuminated, it is natural to start guessing what might be causing the issue. The thing is, most of these causes affect the engine performance directly.
While you can tell the main causes by using an OBD-II scanner, having an idea of where to start will make the work easier. Here, I will discuss some of the most common culprits and how you can fix them:
1. Loose, Cracked, or Missing Gas Cap
If your vehicle’s gas cap is loose, missing, or cracked, it will cause the check engine light to illuminate. The fuel tank needs to maintain a specific pressure and vapor concentration.
If your gas cap is loose, cracked, or missing, it allows vapors to leak out. This will trigger the diagnostic codes and illuminate the check engine light.
SOLUTION
Tighten or replace the gas cap, especially if the check engine light comes on soon after fueling the vehicle.
2. Oxygen Sensor Issues
Another common cause I frequently deal with is the oxygen sensor issue in the vehicle’s exhaust system. Oxygen sensors continuously monitor the exhaust gasses coming from the engine to help regulate the air-fuel ratio for optimal fuel efficiency and emissions.
They are susceptible to degradation over time, most failing after the 80,000-mile mark. An oxygen sensor error sends inaccurate signals to the engine control unit. This can cause drivability problems and illuminate the check engine light.
SOLUTION
- Connect an OBD-II scanner to check for any oxygen sensor-related codes. Pay attention to the sensor location specified in the code.
- Observe the voltage output on a scanning tool. It should switch rapidly between 0.1 and 0.9V. Irregular or flat readings indicate a faulty sensor.
- Test the electrical connection to the sensor. Corrosion or damage to wiring can cause issues.
- Try cleaning or replacing the oxygen sensor. This is often all that’s needed to resolve the issue.
- Inspect for any physical damage to the wiring harness contacting the exhaust. Replace as needed.
- Check for exhaust leaks near the sensor bung. Repair leaks that could affect sensor reading.
- Replace the oxygen sensor if it is past the expected lifespan or voltage testing/code checking confirms sensor failure.
Watch the following video on how to replace an oxygen sensor.
3. Catalytic Converter Failure
Clogged or missing catalytic converters are another culprit I have seen to cause the engine light to come on. This emissions control device in the exhaust system converts toxic gasses and pollutants into less harmful emissions.
With time, carbon and sulfur may clog it, reducing its performance. If the downstream sensor detects a reduction in the converter’s efficiency or the device is missing entirely, the light will also come on.
SOLUTION
- The rate of Catalytic Converter theft in the country is still high. So, I would start by checking if I still have mine. The converter is gone if you see any recent work near the converter housing.
- If it is missing, replace it. I won’t lie – it is expensive but important if you want to pass emissions tests.
- If it is present, take the vehicle to an auto shop to inspect the device for buildup and damage.
4. Engine Misfires
An engine misfire happens when one or more cylinders are not firing properly. This causes the engine to run rough. The fuel and spark are not properly igniting in that cylinder. There are a few common reasons your engine may be misfiring.
Bad spark plugs
Over time, spark plugs wear out and cannot create a strong enough spark. Old, worn plugs cause misfires. Bad spark plug wires can also disrupt the spark, leading to engine misfire at low rpm. If the wire is cracked or damaged, it stops the spark from reaching the plug.
Fuel delivery problems
If the injector is not spraying the right amount of gas into the cylinder, it won’t fire right. Fuel filters getting dirty prevent proper fuel flow as well.
Bad ignition coils
The coil creates the high voltage spark. When coils go bad, they cannot fire the plug. You can test coils by swapping locations to see if the misfire moves.
Bad engine compression
if there is a bent or burnt valve, worn out piston rings, or off valve timing, you will experience misfire. You may have noticed smoke coming from the valve cover if there was an issue with the valves.
Vacuum Leak
A vacuum leak causes air to enter the engine in unintended spots. This disrupts the air-fuel mixture controlled by the fuel injection system. Major leaks are fixed by tightening loose connections or replacing cracked hoses/pipes.
SOLUTION
- Catching a misfire early will prevent further damage. If your engine isn’t firing on all cylinders, I recommend you check those easy things first, like plugs and wires.
- Replace the spark plug wires with signs of wear, such as cracks and damage. Swap out the wires one by one to restore a good spark. If you haven’t tuned up your car at 60,000 miles, I recommend you replace them. Typically, do this after 30,000 to 100,000 miles – check your manual for the recommended range.
- Check the ignition coil for cracks, burns, and melting signs. You can also test the coil using a multimeter. Check the specific resistance for the primary and secondary windings of each coil.
- For the comprehension issues, you will need to perform a comprehension test. If you don’t have the tools, you might want to visit an auto shop near you.
- Use an electronic leak detector or spray solution to identify the source of small leaks. Once sealed, the engine runs as intended, and the check engine light turns off.
5. Mass Airflow Sensor Failure
The mass airflow sensor monitors the air volume entering the engine to determine the fuel injection rate from the fuel injectors. When malfunctioning, it upsets the all-important air-fuel ratio, reduces fuel efficiency and performance, and triggers the check engine light.
Apart from the diagnostic codes (P0101, P0102, or P0103) pointing to the sensor, you might have experienced reduced performance and fuel economy. The mass airflow sensor is sensitive to dirt, water vapor, and oil and can easily get clogged with buildup.
SOLUTION
Try cleaning the sensor with a mass airflow sensor cleaner. If the cleaning doesn’t work, replace the malfunctioning mass airflow sensor and erase the diagnostic code.
Here is a video demonstrating how to tell the mass airflow sensor is failing:
Final Notes
Remote start not working and the check engine light on is a common thing that can be quite frustrating at times. Fortunately, it’s a safety feature designed to protect you and the car. Unfortunately, you need to fix the cause of the check engine light coming on for the remote to start functioning again.
The good news is it might be a simple fix, like tightening your gas cap. However, it might also be a huge problem, like a failing catalytic converter or bad compression. Whichever it is, you need to fix it to restore the remote start functionality.
