P2122 OBD-II Trouble Code: Throttle Position Sensor/Switch A Circuit Low Input

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P2122 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2122 code

P2122 is a diagnostic trouble code (DTC) for "Throttle Position Sensor/Switch A Circuit Low Input". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $79.99. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$79.99$20.00
Toyota$79.99$20.00
BMW$79.99$20.00
SCHEDULE P2122 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

P2122 trouble code definition

The P2122 OBD-II trouble, or fault, code means that the vehicle’s on-board computer has detected low voltage in the throttle position sensor (TPS), which is usually below 0.17 volts.

What the P2122 code means

The registration of the P2122 trouble code simply means that low voltage has been detected in the TPS. Depending on the vehicle’s make and model, this detection may trigger a forced engine shutdown, forced idle, or forced reduction in power output to prevent overloading circuitry.

What causes the P2122 code?

While there are multiple potential causes for the P2122 fault code registering, one of four components is likely defective - the throttle position sensor, the throttle actuator control motor, the throttle position actuator, or the pedal position sensor. If all four of these parts are in good working condition, the cause may lie in damaged wiring, connectors, or grounds.

What are the symptoms of the P2122 code?

While the most obvious symptom of the P2122 code is the illumination of the Check Engine Light on the dashboard, the following symptoms may also be noticeable:

How does a mechanic diagnose the P2122 code?

To begin diagnosing the cause of the P2122 trouble code, first verify its existence. A qualified technician can do this through the use of a specialized scan tool that collects data about the vehicle’s performance and reports any anomalies in the form of OBD-II trouble codes. Once a mechanic has performed a scan and the P2122 code registers, then further tests and/or inspections are necessary to narrow down potential culprits.

The next step is often a visual inspection of all wiring and connectors; if damaged wires or connectors are found, they are replaced. The mechanic then clears the trouble code from the computer’s memory and uses the specialized scan tool again. If the P2122 code does not register, the issue is likely resolved. On the other hand, if the code registers again, additional diagnostic efforts are needed.

Using a digital volt/ohmmeter, a mechanic can then check the voltage readings through the throttle position sensor, the throttle actuator control motor, the throttle position actuator, and the pedal position sensor. This will help determine if any of these components is responsible for the low voltage detected by the on-board computer, so faulty parts can be replaced. A technician can also check the voltage through wiring, grounds, and the CAN bus network in order to repair or replace any worn or damaged parts.

Once repairs have been made, the mechanic will clear the OBD-II fault code, scan for anomalies again, and possibly test drive the vehicle to ensure the issue has been satisfactorily resolved.

Common mistakes when diagnosing the P2122 code

Once the P2122 code registers, mechanics sometimes make the following mistakes:

  • Failing to address trouble codes in the order of appearance, when multiple codes register
  • Failing to verify the existence of the P2122 code
  • Failing to clear the P2122 code from the on-board computer following repairs

How serious is the P2122 code?

Although some vehicles do not enter a no-start condition after the P2122 fault code registers, it does not mean the issue that caused it should be ignored. Whether the root cause of the code registering is a faulty component or loose wire or something else entirely, failing to repair the problem has the potential to negatively affect other parts or systems. This ultimately can incur greater cost and hassle in repairs than it would in prompt attention to the matter.

What repairs can fix the P2122 code?

Once the registering of the P2122 trouble code is deemed valid with the use of a specialized scan tool, the following action(s) may be necessary:

Additional comments for consideration regarding the P2122 code

In the diagnosis of the P2122 code, it is possible for the process to take up to several hours. This is due to the potential need for multiple tests with a scan tool or voltage meter, hands-on inspections, and test drives. In being thorough from the start, the chance of other related problems cropping up is greatly reduced.

Need help with a P2122 code?

If you would like help in diagnosing and addressing the P2122 OBD-II fault code, reach out to YourMechanic to be connected with a qualified technician. This diagnostic and repair professional can even come to your home or office for your convenience or safety. Book an appointment online, get a quote for the cost of repairs, or discuss the possibilities with a representative at 1-800-701-6230.

trouble codes
Check Engine Light
throttle position sensors

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P2122 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

4,255

Rating Summary
3,898
174
45
26
112
3,898
174
45
26
112
Ben

Ben

39 years of experience
1020 reviews
Ben
39 years of experience
Lexus LS430 - Check Engine Light is on - Houston, Texas
I was very pleased with the courtesy and work of Mr. Smith. He was exceptional in explaining and correcting the problem and thereby gained my trustI . I request he be my mechanic in all future service requests. I had a great experience working with Mr. Ben Smith.
Richard

Richard

19 years of experience
203 reviews
Richard
19 years of experience
Ram ProMaster 1500 - Check Engine Light is on - Bonita Springs, Florida
Prompt, polite and personal. Took the time to explain the process and his recommendations. 2 thumbs up
Michael

Michael

23 years of experience
37 reviews
Michael
23 years of experience
Ford F-150 - Check Engine Light is on - Federal Way, Washington
Very helpful and explained everything and what needs to be addressed. I feel informed and confident in Mike’s assessment and look forward to him performing services on my vehicle.
Rigoberto

Rigoberto

9 years of experience
650 reviews
Rigoberto
9 years of experience
Honda Civic - Check Engine Light is on - Chicago, Illinois
Rigoberto came on time & quickly diagnosed the problem- rats chewed thru wiring near the battery. He wasn’t able to fix it himself bc of parts, but gave me recommendations on where to go & how to not have the dealership sell me services that are not needed.

More related articles

Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...

Related questions

Q: Step by step troubleshooting of DTC fault codes

Each of these codes are for different components and since you swapped the motor with a different size motor than what the car had may be a big problem. You would need to have each code diagnosed separately to see...

Q: What parts will I need for a timing chain replacement and how many of each. Is my engine interference or non interference?

Hello - your engine does use a timing chain, and that engine is not an interference (valve-to-piston) engine. However, having said that - if the chain breaks, especially at anything above an idle, the broken chain can jam the crankshaft...

Q: Intermittent miscommunication between acc. pedal and throttle body 2007 Mazda CX-7

Hi there, from your symptom description, it sounds like your throttle position sensor is failing. Check for problem codes, whether the Check Engine or electronic throttle warning lights are on. I would recommend an engine inspection by a mobile, professional...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com