What the OBD-II code p0122 means

Fault code P0122 – a step-by-step guide to diagnosing and fixing it

The meaning of error code P0122 – Throttle Position Sensor/Switch A Circuit Low Input
P0122
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P0122: causes, symptoms and repairs

The meaning of fault code P0122

DTC P0122 is triggered when the onboard computer has recognised that the throttle position sensor (TPS) circuit As voltage output is lower than the normal range. The sensor monitors the car throttle body's movement. As the component opens, it generates a voltage. This range will vary depending on the make of the vehicle, however, the code typically appears when the circuit voltage is below an 0.17– 0.2 V limit for 8 seconds or more.

Possible causes of error P0122

  • Installing the device incorrectly. This is a likely cause if it has recently been replaced or removed. Some devices have to be installed in a specific position or angle to function properly. There could also be problems if the device is not secure.
  • A short or broken circuit in the power supply wire or signal wire.This could be due to harsh operating conditions causing damage to the wire’s insulation sheath.
  • Corroded electrical contacts resulting from exposure to dirt or moisture. This can occur when the connector cable isn’t securely attached to the device.
  • A damaged or faulty control module. Although this is rarely the cause, it shouldn’t be ruled out entirely before a diagnosis has been made.
  • A fault with the TPS itself
Symptoms to look out for

  • Activation of the check engine light
  • Stalling or surging, particularly during gear changes
  • A rough or high idle
  • Hesitation or reduced acceleration
  • A loss of engine power
  • A decrease in fuel efficiency
Recommended repairs

  • Run a diagnostic scan to see whether other DTCs are present. To do this, you will need to connect an OBD2 scan tool to the onboard computer via the data link connector port. This will help you to identify the exact cause of the fault. The codes can also be reset after each repair.
  • Make sure that the TPS has been installed properly and make adjustments if necessary. Refer to the vehicle’s repair manual for specific instructions on how to install, adjust, or replace the component. Some devices come with a special adjustment screw.
  • Replace any damaged or faulty wires and connectors, and clean the contacts to remove any rust. There are cleaning products that are specially designed for improving the conductivity of the electrical components.
  • If the P0122 code is still appearing, the sensor itself could be malfunctioning. You can check whether it works by measuring its voltage with a digital multimeter. Install a new one if this value is too low.
Frequently Asked Questions (FAQ)

What does the code “P0122” mean?


It means that a low voltage output has been detected from one of the throttle position sensor circuits.

What causes the fault?


It could arise as a result of a number of common electrical problems such as a short or open circuit or corrosion, as well as issues with the device itself such as installation errors.

How do I erase this DTC?


Firstly, you can reset it by disconnecting the negative battery terminal to restart the computer or using the OBD2 scanner. If it is triggered again, you may need to consult a professional for a full diagnosis and repairs. This normally involves simple replacements.

Can I still drive my car, or is it too serious?


It is possible to drive it, although not recommended. The engine control unit may activate the failsafe mode, seriously affecting the driveability of the vehicle. Frequent stalling and poor acceleration could make the car unsafe and increase the risk of engine damage.

Cars the fault code P0122 is most commonly found on

Fault code P0122 - Throttle Position Sensor/Switch A Circuit Low Input can occur with any car but is most often found on the following cars:

  • Ford: Focus, Fiesta, Ka
  • Peugeot: 206, Partner
  • VW: Golf
  • Honda: Civic, Accord
  • Mercedes
  • Citroen: Berlingo

If you get the code P0122 on your car, make sure that the diagnostics are carried out correctly and the error is still relevant. Check for symptoms associated with the problem and explore options for resolving it.

What to do if the fault code p 0122 appears

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