P0122 Throttle Position Sensor / Switch A Circuit Low Input

OBD-II Trouble Code - P0122 - Data Sheet

Low input signal in the throttle position sensor / switch A circuit

What does DTC P0122 mean?

This Diagnostic Trouble Code (DTC) is a generic transmission code and applies to many OBD-II vehicles (1996 and newer). This may include, but is not limited to, Honda, Jeep, Toyota, VW, Chevy, Ford, etc. Despite the general nature, the exact repair steps may vary depending on the model year, make, model and transmission configuration.

The P0122 code means that the vehicle computer has detected that the TPS (Throttle Position Sensor) "A" is reporting too low a voltage. On some vehicles, this lower limit is 0.17–0.20 volts (V). In simple terms, the throttle position sensor is used to determine which position the throttle valve is in.

Did you customize during installation? If the signal is less than 17V, the PCM sets this code. This could be an open or short to ground in the signal circuit. Or you may have lost the 5V reference.

For more information on TPS, see What is Throttle Position Sensor?

Example of a Throttle Position Sensor TPS:

Symptoms

Symptoms may include:

• Illumination of the corresponding engine warning light on the instrument panel.
• Activate fail-safe mode to bring the throttle to about 6 degrees open.
• Decreased actual vehicle speed.
• General engine malfunctions (difficulties in acceleration, starting, etc.).
• The engine suddenly stops while driving.
• Rough or low idle
• Very high idle speed
• Stalling
• No / slight acceleration

These are symptoms that can also appear in combination with other error codes. Other symptoms may also be present.

Causes of the P0122 code

In an internal combustion engine, the throttle valve regulates the amount of intake air and, depending on the degree of its opening, the air-fuel mixture reaches the cylinders to a greater or lesser extent. Thus, this component has a fundamental impact on the power and performance of the engine. A special TPS sensor informs the fuel injection system how much mixture the engine needs, depending on the driving situation, so that it can work at maximum efficiency. If the throttle position sensor is working correctly, the vehicle's handling during acceleration, approach or overtaking maneuvers will be optimal, as well as fuel consumption.

The engine control unit has the task of monitoring the correct functioning of this component, and as soon as it registers an anomaly, such as, for example, that the output signal of the sensor circuit is below the limit value of 0,2 volts, it causes a P0122 trouble code. work immediately.

The most common reasons to trace this error code are as follows:

• Throttle position sensor (TPS) malfunction.
• Wiring failure due to exposed wire or short circuit.
• Throttle position sensor circuit malfunction.
• TPS is not securely attached
• TPS circuit: short to ground or other wire
• Damaged computer (PCM)

Possible solutions

Refer to the specific vehicle repair manual for the location of the "A" TPS circuit.

Here are some recommended troubleshooting and repair steps:

• Thoroughly check the Throttle Position Sensor (TPS), wiring connector and wiring for breaks, etc. Repair or replace as necessary
• Check the voltage at the TPS (see your vehicle's service manual for more information). If the voltage is too low, this indicates a problem. Replace if necessary.
• In the event of a recent replacement, the TPS may need to be adjusted. On some vehicles, installation instructions require the TPS to be properly aligned or adjusted, refer to your workshop manual for details.
• If there are no symptoms, the problem may be intermittent, and clearing the code may temporarily fix it. If so, then you should definitely check the wiring to make sure that it is not rubbing against anything, not grounded, etc. The code may return.

COUNCIL: A visitor to our site suggested this tip - Code P0122 can also appear when the TPS is NOT ROTATING when installed. (The tab inside the sensor MUST touch the rotating pins in the throttle body. On a 3.8L GM engine, this means insert it with the connector 12 o'clock before turning it 9 o'clock for the final mounting position.)

Other TPS Sensor and Circuit DTCs: P0120, P0121, P0123, P0124

Repair Tips

After the vehicle is taken to the workshop, the mechanic will usually perform the following steps to properly diagnose the problem:

• Scan for error codes with an appropriate OBC-II scanner. Once this is done and after the codes have been reset, we will continue to test drive on the road to see if the codes reappear.
• Visual inspection of throttle position sensor (TPS) connections.
• Visual inspection of the wiring for short circuits or exposed wires.
• Throttle valve inspection.

Rushing to replace the throttle position sensor without first performing these checks is not recommended. In fact, if the problem is not in this component, the error code will appear again and useless expenses will be incurred.

Generally, the repair that most often cleans up this code is as follows:

• Replacing or repairing the TPS connector.
• Replacing or repairing wiring.
• Replacing or repairing the throttle position sensor (TPS).

Since the vehicle may have handling problems on the road, driving with this error code is not recommended as it will compromise the safety of the driver and other drivers. Therefore, the best solution is to entrust your car to a good mechanic as soon as possible. Also given the complexity of the interventions required, a do-it-yourself option in a home garage is not feasible.

It is difficult to estimate the upcoming costs, since a lot depends on the results of the diagnostics carried out by the mechanic. Usually the cost of replacing the throttle sensor in the workshop is about 60 euros.

Frequently Asked Questions (FAQ)

What does code P0122 mean?

DTC P0122 registers abnormal voltage in the throttle position sensor.

What causes the P0122 code?

Triggering of this DTC is often associated with a bad throttle or a wiring problem.

How to fix code P0122?

Check the throttle body and all connected components along with wiring.

Can code P0122 go away on its own?

In some cases, this code may disappear on its own. In any case, it is recommended to check the throttle valve.

Can I drive with code P0122?

Driving a car with this code is possible, even if the characteristics are not up to par, but undesirable.

How much does it cost to fix code P0122?

On average, the cost of replacing a throttle sensor in a workshop is about 60 euros.

P0122 Fix, Solved and Reset

Need more help with the P0122 code?

If you still need help with DTC P0122, post a question in the comments below this article.

NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.