2003 Accord EX TPS (Throttle Position Sensor) problem?

Car: 2003 Honda Accord Coupe EX 2.4


I cleaned the air induction by pouring in Seafoam Brand (Cleans Well),

so I had to remove the hose last month and for some stupid reason I

forgot to plug the TPS back in. I just noticed this today, as I was

going to replace the TPS thinking it was bad, as my check engine light

is on. I noticed right away when I located the TPS that it was not

even plugged in... So I plugged it back in and still the check engine

light is on.

Last month there was no check engine light on.

So I can scan for engine codes, I purchased this product named AutoTap

Express, you plug the device into your cars computer and then run

software on your laptop, kind of like what dealerships use and you can

read engine colds and do other things. When I checked what the check

engine light codes were I got this.

P0420 - Catalyst System

P0171 - Fuel TrimSystem Loan Bank 1

P0122 - Throttle Position Sensor Circuit Low Voltage


My question is, by forgetting to not plug the TPS back, did I damage

my car? I have been driving it without the TPS plugged in now for a

month. I have noticed that the car burns a lot more gas than normal

and when idleing you can smell the gas, as if it is not properly being

burned correctly. Also, by not having the TPS plugged in on the top of

the TPS to the Engine, would this cause the TPS to go bad?

Thank you!


" catalytic converter " --- I would not be surprised if it has already gone bad now. Which sucks, as I just put in a new one last summer.

3 Answers

  • Anonymous
    10 years ago
    Favorite Answer

    Agree with Mike,

    Once you have plugged your TPS back in use your "Auto Tap Express" tool and reset your cars computer. (BTW...it is not the same as a dealer uses... a dealer uses a $20,000 manufactures tool ..you have the OBD code reader..it is a GOOD tool to have but it is NOT a diagnostic tool..it just points you to the symptom of the problem. Then you get to diagnose what is causing the symptom.

    With the TPS disconnected your car was using other sensors to estimate how much you were pressing on the gas pedal. Then for good measure probably adding a bit of extra fuel.

    The P0171 and P0122 codes will go & probably stay away after driving a bit for the fuel trim system to get your back to "normal". (The cars computer added extra fuel trying to get that Lean P0171 to get back in the normal range but once it adds fuel up to the limit of what the computer is allowed to do it turns on the code/light.

    The P0420 code will probably come back and turn on your MIL (Check Engine light) for a while and MIGHT go away after some good highway driving to possibly burn off the contaminates on your Cat. After you take a GOOD trip on the Highway use the Auto Tap and reset the computer again... And if the MIL comes on again with the P0420 code yes you probably will need to replace the Cat before your next emissions (smog) test. The TPS is going to be OK... it's the CAT that might not come back

  • 4 years ago

    2003 Honda Accord Throttle Position Sensor

  • Mike
    Lv 4
    10 years ago

    If you can smell gas, your car is running too rich (too much fuel). Try resetting the codes and see if they come back up. Driving a vehicle that is running rich will overheat and destroy the catalytic converter. If you reset the codes and you still get P0420, you are going to have to replace the converter.

Still have questions? Get your answers by asking now.