P1122
HondaThrottle Position (TP) Sensor Circuit Intermittent Low Voltage
Medium SeverityThis code means the Throttle Position (TP) sensor isn't giving a consistent low voltage reading to the computer. When that signal drops out, the engine control unit gets confused about how much gas you're trying to give it, which messes with engine operation.
⚠️ Before You Begin (Safety First)
Don't mess with wiring or components while the engine is running. Always disconnect the battery before doing any electrical work to avoid a shock or frying something.
Common Symptoms
- Engine light is on
- Engine idles rough or stalls
- Hesitation or surge when accelerating
- Poor fuel economy
- Cruise control stops working
Common Causes
- Bad Throttle Position (TP) sensor
- Frayed or damaged wiring to the TP sensor
- Corroded connector at the TP sensor or ECM
- Loose connection at the TP sensor
- Internal short in the TP sensor circuit
Frequently reported on: Honda Civic (2001-2005), Honda Accord (1998-2002), Honda CR-V (1997-2001), Honda Odyssey (1999-2004)
Diagnostic Steps
- First, check the engine light with a scanner to confirm it's P1122.
- Visually inspect the TP sensor and its wiring harness for any obvious damage, frays, or loose connections.
- Unplug the TP sensor connector and check for corrosion on the pins. Clean them if necessary.
- With the key on, engine off, use a multimeter to check the voltage at the TP sensor's signal wire while slowly moving the throttle. It should sweep smoothly from low to high voltage without drops.
- If the sensor tests bad or shows intermittent readings, replace the Throttle Position Sensor.
- Clear the code and test drive the vehicle to see if the issue comes back.
👨🔧 When to Call a Professional
If you've checked the wiring and replaced the sensor and still have issues, it's time to get it to a pro. You might have a deeper electrical problem or a bad ECM.
Commonly Asked Questions
Can I drive with a P1122 code?
You can, but it might act up and stall or run rough. Not something I'd recommend for long.
What's the throttle position sensor do?
It tells the engine computer how much you're opening the throttle. Basically, how much gas pedal you're giving it.
Do I need special tools to fix P1122?
A basic multimeter for testing and a scanner to clear codes are good to have. Other than that, standard hand tools usually do the trick.
Can a dirty throttle body cause P1122?
Not directly. A dirty throttle body causes other issues, but P1122 is about the sensor's electrical signal, not the air passage itself.