P1125
SubaruThe Powertrain Control Module (PCM) detected an intermittent signal from the Throttle Position (TP) sensor circuit. This means the signal voltage wasn't consistent like it should be.
Medium SeverityThis code means your engine computer saw the throttle position sensor acting up. It wasn't giving a steady signal. That messes with how the engine fuels and shifts.
⚠️ Before You Begin (Safety First)
You gotta be careful when the throttle acts funny. Your engine might not respond right. Don't mess with wiring near the accelerator pedal if you don't know what you're doing. Get it checked if the car starts running real bad.
Common Symptoms
- Check Engine Light is on.
- Engine feels like it's surging or hesitating.
- Rough idle, might even stall.
- Automatic transmission might shift hard or at weird times.
- Cruise control probably won't work.
Common Causes
- Bad connection at the TPS itself.
- Wiring got chafed or corroded somewhere between the sensor and the computer.
- The TPS itself is faulty, just worn out from age.
- Water got into the connector or the sensor housing.
- Rarely, the PCM is bad, but check everything else first, always.
Frequently reported on: 2005 Subaru Outback, 2008 Subaru Forester, 2010 Subaru Impreza, 2012 Subaru Legacy
Diagnostic Steps
- Hook up your scanner, check for any other codes first. Always start there.
- Locate the Throttle Position Sensor. It's usually bolted right to the throttle body.
- Visually inspect the TPS connector and the wiring harness leading to it. Look for frayed wires, cracks in the insulation, or corrosion.
- Unplug the connector. Clean it out good with electrical contact cleaner, especially if it looks dirty or corroded.
- Plug it back in tight. Make sure it clicks and feels secure.
- If you got a multimeter, check the TPS signal voltage. It should go smooth from low to high as you open the throttle by hand, no dropouts.
- Clear the code. Take it for a drive, see if it comes back. Sometimes it's just a loose connection.
👨🔧 When to Call a Professional
If you can't find the bad connection or the sensor test comes back screwy, hand it off. Don't just throw parts at it without checking the wiring first. Sometimes it's the computer, and you don't want to mess with that.
Commonly Asked Questions
What's this sensor do?
It tells the computer how much gas you're trying to give it. Like a gas pedal gauge for the engine. It's critical for fuel delivery and transmission shifting.
Can I drive with this code?
You can, but it's gonna run bad. You might have unpredictable power, hesitation, or even stall out in traffic. Get it fixed sooner rather than later.
Is it expensive to fix?
The sensor itself ain't usually pricey, maybe 50-100 bucks. Labor depends on how easy it is to get to and if the wiring's messed up. That's where costs can climb.
How often do these fail?
They usually last a long time, but connections get old, wires break from vibration, or the sensor just wears out over years. It happens.