Why is my “check engine” light on after using Sea Foam Spray? [SOLVED]

Thanks for the question Hernan. Applying Sea Foam Spray through the intake can cause a misfire code during the treatment. Understand that you’re adding something unusual to the upper engine’s fuel and air mix during the cleaning application, so it might take up to 20 post-treatment driving miles for your Dodge’s engine sensors to re-adjust to normal. If the check engine light (CEL) remains, you can disconnect the negative cranking battery connection for a few seconds to clear the CEL. Hope this helps!

I never got smoke. Now my engine light is on. The only smoke I got was when I revd high down the road. For 1 second. That’s it. Now engine light.

3 things to consider: 1) Smoke means nothing. 2) Your check engine light is probably a misfire code that will correct once you go back to normal engine operation. 3) Have the code checked to determine the cause. If a misfire code, just cancel it out. Nothing to worry about. Hope this helps!

I used the Sea Foam intake spray as directed and after approximately 80 kms the check engine light came on. It’s showing code P0420 which is a catalytic converter below threshold. Cleared the code once and it came back after another 80kms. What is my fix here?

Hi Will. A catalytic converter issue would not be related to using Sea Foam Spray. [And we agree that the cause/effect is reasonable.] Was the P0420 paired with another code? What’s the odometer reading?

Hey Brian, thanks for getting back to me. The first time the check engine light came on it was paired with a rich fuel code. Which makes sense with the Sea Foam. After clearing the initial two codes only the P0420 came back. Could the catalytic converter be getting clogged with everything the the Sea Foam knocked out of the top end of the engine?

No, catalytic converter issues are typically related to too much heat, misfires, or leaks.

I have a 2004 2.3 Ranger. Same thing happened to me. Tried battery disconnect. Check engine light is still on. Could Sea Foam Spray have fouled the O2 sensor?

Hi Paul,

Sea Foam Spray would not have fouled the O2 sensor. Do you know the specific check engine code? (Most parts stores will read them for free).

Let us know what you find and go from there!

Hey guys. I have the same issue as well since adding a full spray can into the throttle body (followed instructions). Sea Foam worked great on my past cars. This car shows a P1157 code which is the primary 02 sensor indicating lean. I also cleared the code but the light came back on. I’m not sure if I have to replace it since I’ve been driving it for about 70-80 kms now and CEL is still on. No other codes. Any help would be greatly appreciated.

Hi Abi. If your vehicle has over 125,000 odometer miles and you get an O2 sensor code that won’t clear (comes back after clearing)… it’s likely that the O2 sensor is at the end of it’s useful life/needs replacement. Hope this helps!

I put seafoam in trying to pass smog my check engine light came on do u keep driving it out of car. It happe6to my last car finally went off

Hi Michelle,

Yes, clear the code and keep driving. Should resolve itself. If the check engine light remains, disconnect the negative cranking battery connection for a few seconds to clear the check engine light.

Hope that helps!

Had cylinder #2 misfire so changed spark plugs an cleared code. Than same code came back so I added Sea Foam. Cleared code. Now code came back for cylinder head over temperature. I changed the CHT sensor but same code… What should I do next?

HI Dana. Have you considered ignition coil/wiring replacement? Any idea what’s causing the cylinder to overheat?

I applied Sea Foan intake head and turbo cleaner in 2017 Hyundai Accent, got a lot of smoke and car runs much better except the big issue of the P0638 code for actuator control range/performance Bank 1. This has not resent after over 10 driving times and at performance speeds. YouTube videos warned not to get this spray in the wiring of the throttle body. I was extremely careful but am question did some make it onto wiring? or manually opening the throttle to insert the spray straw somehow cause the issue…I don’t know but something has happen I cant figure out

There is a known problem with the 1.6L Hyundai engine throttle body, after a throttle body clean, intake clean or GDI service. There is a very simple process to reset or initialize the throttle body.

1. Visually inspect the throttle bore. Clean and initialize as necessary.

2. Check the resistance of the throttle motor. The specification is 1.38 ohms at 23°C (73.4°F). Replace as necessary.

3. Verify that the throttle plate moves smooth and freely when cycling the ignition or when raising and lowering the RPM. If the throttle movement is not smooth or it binds, the throttle body should be replaced.

After all the above steps have been verified, the next step is to initialize the throttle body.

Throttle Body Initialization Procedure: Erase the trouble codes in PCM. Turn the ignition key “OFF” until the main relay turns “OFF”. (It will take about 10 sec.) Turn ignition key “ON” for more than 3 seconds to record the throttle motor position in the Engine Control Module. Start the engine and let it idle until the cooling fan comes on.

Hi, we have a 2009 Acura TL with over 200k miles that started up with a very rough and shaky idle last week. The car did not stall out, but it sounded like it would unless you increased the rpms. The car seemed to drive fine, but there was an oil and battery warning light present. The car had no unresolved issues prior and had been given a clean bill of health at the Dealer in January. A friend scanned the car and said the spark plugs were bad, so he replaced them, the battery seemed fine, but he did not test the alternator, but the rough idle continued so the spark plugs were not the issue. So, I added a can of Sea Foam, after learning about it, to the existing 3/4 tank of fuel and the rough idle at start-up has since disappeared and the car is driving fine. However, the car now has a check emission system warning light on. I bought a OBD2 scanner and the codes came back P0171 and P0174 “System too Lean”. Do you think we just need to get through a few tanks of gas to resolve this, and reset the code, or should we take it to the dealer? I hate taking it to the dealer as its always a huge expense. Thanks!

Hi Sonja,

Thanks for the detailed description and question! I sent you an email response as well. Here’s what our tech expert, Richard, said in response to your question…

“Typically when Sea Foam Motor Treatment is added to gasoline, regardless if there is a Check Engine Light on before or not, Sea Foam Motor Treatment will not cause your engine computer to set codes and illuminate the Check Engine Light. The codes that you have set mean that there is too much air in the exhaust system, basically the computer is telling the technician that there could be a vacuum leak, possible bad sensor or not enough fuel being supplied.

My advise is to take the vehicle back to the mechanic that installed your spark plugs before you take it to the dealer for diagnosis. Based on the information that you’ve provided and my knowledge of vehicles, your Acura TL has a V-6 engine that is difficult to access the rear spark plugs. The technician could have inadvertently left a vacuum hose or sensor disconnected. If no problems are found, then you could have them diagnose the cause of the codes or take the vehicle to the dealership for diagnosis.”

WHAT. IF. THAT. MAKE. MY. CHECK. ENGINE LIGHT. GC. OFF. THEN. WHAT. SHOULD. I. DO

Hi Dean – if you are asking about what to do if a Sea Foam Spray treatment made your check engine light go on, follow Jim’s directions:

“Applying Sea Foam Spray through the intake can cause a misfire code during the treatment. Understand that you’re adding something unusual to the upper engine’s fuel and air mix during the cleaning application, so it might take up to 20 post-treatment driving miles for your Dodge’s engine sensors to re-adjust to normal. If the check engine light (CEL) remains, you can disconnect the negative cranking battery connection for a few seconds to clear the CEL. Hope this helps!”