P0122: Throttle/Pedal Position Sensor/Switch A Circuit Low
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Expect limp mode - drive gently to a shop, avoid highways.
Symptoms
- Reduced power mode
- High or stuck idle
- No response to pedal in severe cases
Likely causes, most common first
- TPS circuit shorted low
- Connector or harness damage
- Failing throttle body sensor
Read P0122 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0122 means the throttle position signal dropped below its plausible range. Drive-by-wire systems treat throttle sensor faults as safety events - power is cut rather than guessed.
Modern throttle bodies use paired sensors that cross-check each other; a disagreement or a dead signal triggers exactly this response. Repair usually means the throttle body assembly plus a relearn procedure.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0122
“The check engine light comes on; check and advise. The Ford dealer performed an EEC test, retrieved codes P1674 and P0122, tested the system, and found the wiring harness rubbing at the intake manifold. They disassembled to gain access, repaired the wiring harness at the engine, wrapped and re-routed the harness, cleaned all codes, and retested. It passed the road test and was OK, but the dealer charged me for this harness repair, and I found that this exact issue was subject to a Ford Motor Company safety recall (Recall 14S17 / NHTSA Recall 14V-495) concerning the engine wiring harness.”2014 Ford Focus · Mar 2025
“While driving down the high way car began to sputter and jolt felt much like someone slamming on brakes aggressively and then releasing and motor stopped completely. Was able to pull over and put hazards on. After running diagnostics test discovered that the TAC system was faulty. Codes: P0122 , P0223 , P0110 . Car will start and idle briefly and some times drive down the road but always ends up dying while driving abruptly and hazardously without warning. Car still will start but scared to drive it for fear of causing domino effect on damaging the car. Would like the limited warranty on this product to apply to fixing this problem.”2009 Ford Fusion · Jun 2022
“Wrench light came on a few times when I checked it the codes were p2135 and p0122 and p1576 car didnt accelerate It happen again one time and then it was letting me accelerate but it was very limited”2010 Lincoln MKZ · Oct 2021
Show 7 more owner reports
“Constantly get a shudder at low rpm's 30-50mph- like the car does not know what gear it wants to be in. Also recieve p0122 code of throttle after fast acceleration. Taking this to performance engine place to diagnose”2016 Chevrolet Camaro · Apr 2020 · 8,900 mi
“Driving in stop and go traffic. Stopped at lite. Check engine lite came on. No power. Had to idle home. Obdii codes p0122, p0222, p2111. P2135. Tps reading stuck at 82%. Defective throttle body. *js”2012 Ford Transit Connect · Dec 2015 · 367,272 mi
“The vehicle was driving normal in suburban traffic. Stop & go with speeds up to 40 mph. During stop at light the check engine lite came on and the vehicle would not accelerate. The yellow check engine lite is on. The vehicle is in limp mode. Obdii codes: p0122, p0222, p2111, p2135. Throttle body failure. *js”2012 Ford Transit Connect · Dec 2015 · 37,272 mi
“Vehicle will not operate over 1,000 rpm. It had the throttle body cleaned on 15 aug 2013 under customer satisfaction recall 12n03. For the original complaint, the idling spiked where in this instance the car will not accelerate above 1,000 rpm. The codes associated with this incident are: p060b; p061b; p0122; p0155; p0222; p0316; p0480; p2104; p2110; p2122; p2127; p2132; p2135. *tr”2007 Ford Freestyle · Jan 2014 · 145,000 mi
“I brought the car in april while driving home from the dealer I noticed that when applying the brake (slowly) before coming into a complete stop the brake pedal would lock up, release and then come to a complete stop slow acceleration I wasn't able to pick up speed once it did the check engine light would come on code p0122 throttle pedal position sensor. *tr”2005 Honda Accord · May 2010
“Problem: sudden acceleration due to defective throttle body. The idle rpms are excessive upon startup and lead to sudden acceleration during braking to a stop. Background: malfunction lamp light was constantly turning on and off. Took the car to a honda dealership and they only found the error code for the o2 sensor. Later took it to a local mechanic to fix the o2 sensor and they found a defective throttle body (error code p0122). There are several forums which address this exact issue on 2002-2004 honda crv. *tr”2004 Honda CR-V · Mar 2010 · 77,000 mi
“Engine dtc p0122, (low-volts on the tps). It started to set on my 2005 civic dx. If there is a problem with this engine then publish it for heavens sakes ! *cn”2005 Honda Civic · Jan 2010
Cars that report P0122 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0122?
Expect limp mode - drive gently to a shop, avoid highways.
How much does it cost to fix P0122?
Typical US repair costs range from $80 for the simplest fix (wiring or connector repair) to $800 in the worst case. The right number depends on which cause your car has - see the causes list.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.