2000 Honda Civic Si P0122 and P0505 error

Jojji · 10-01-2009

I have a 2000 Honda Civic Si, with 117k miles on it. I have had the 100k maint done to the vehicle and I have kept it in very good shape since I bought the vehicle 3 years ago at 93k miles. Today it started to hiccup on the road and I had the advanced auto parts check the computer.

P0122 TPS/Pedal Position Sensor A Circuit Low Input was the issue that came up. I've done some reading and some people are saying you have to buy the whole Throttle body kit, while others are saying just to buy the sensor. Can anyone here give me any advice on what I should do with this?

P0505 Idle Control System Malfunction. This is the problem I've had since I've had the car but it didn't do anything to performance. I did however replace the idle air control motor but that didn't stop the issue. The honda store couldn't replicate the problem after resetting the engine. The only thing I can think of is the aftermarket air filter on the car. Again does anyone else have an experience with this type of issue?

I do appreciate the time and I hope to hear from you soon.

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gearbox · 10-01-2009

try to clean the idle air valve again and see if it helps. could also be the fast idle thermo valve if you have one. for the tps problem, you need a whole new throttle body, usually the tps cannot be replaced easily, and it needs to be calibrated. it costs more than getting a used tb on ebay for $50. make sure you get the right throttle body for auto or manual trans. and get new gaskets if they are old.

Jojji · 10-01-2009

Thank you for that information! I am a car novice but I do have a mechanic I can trust. How could I tell if there is a thermo valve to check like you mentioned before hand? And he was able to get a used TB from a "You pull it" lot.

gearbox · 10-02-2009

the idle and thermo valves are usually located on or near the throttle body and intake mani. any small sensor looking pieces that look like you can unbolt them easily can be taken off and cleaned with carb spray. i think after 2000, most cars only have iac valve. you prolly have more sensors.