Error Code P0122: What It Means & What To Do?

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Circuit Low Input codes read when there is a low battery voltage (that does come with many possible outcomes), where negative connections are being sent across electrical connectors or earlier fixed wiring, including damage in electrical connections.

Low input voltages are the result of other possible causes that include insufficient poor installation of aftermarket parts, bad quality aftermarket parts like fuses, relays and switches, and moderation of the electrical system that may come with using conductors not valued for use for a certain application. Regardless, negative connections frequently cause high resistances in some of the circuit’s parts, making it crucial to execute resistance and progressive checks during the procedure of diagnosis.

What causes this problem with the Throttle Position Sensor/Switch A Circuit? 

• Not securely mounting TPS
• Short circuit TPS to ground or another wire
• Defected TPS
• Corroded

1. Boost Pressure Sensor - If the boost pressure sensor fails, you will notice the boost is losing power and your engine is decreasing in efficiency. If your boost pressure sensor is damaged, you should have it replaced to stop your turbocharged car from losing its effectiveness.
2. Turbocharger - Low oil levels may lead the turbocharger to fail, as this happens, excess heat and friction will ultimately founder the bearings that are inside. It’s best to restore the turbocharger or use the lubricants inside to ensure the parts are moving coherently.
3. Supercharger - A supercharger can begin to fail for a wide range of reasons, for instance a low rating of supercharger oil, broken pulley, and seals/gaskets that are overheated or defective. If your car's supercharger is not performing correctly, you need to restore it immediately.
4. Knock Sensor - When detecting a knock sensor, ensure that the terminal is not damaged or the wires and connections are not corroded. A defective knock sensor decreases your car’s performance, which brings up the costs of fuel consumption and damage to your engine, so it’s important to get that particular knock sensor for your kind of manufactured car.
5. Spark Plug - A defective spark plug may take place during a process of slow acceleration, power loss, downscale fuel economy, engine misfires, and complications starting the car. As a result, it is much required to restore your car’s spark for every 30 months or 30,000 miles.
6. Intake Manifold - A leaking intake manifold can have destructive effects on your car's engine, inducing the manifold to suck in extra air from outside through the leak, which results in more air accessing intake ports and obstructing with the air-fuel proportion in the cylinders. You should pursue replacing the defective manifold as soon as possible to stop any further going damage to your car's engine.
7. Boost Pressure Gauge - If the boost pressure gauge defective, you will notice a reduction of boost power and a decrease of efficiency in your engine. If there is corrosion to your boost pressure sensor, you should replace it to prevent your turbocharged car from facing a loss of efficiency.
8. Powertrain Control Module - A defective PCM may inflict your car in failing to start or begin stalling when running. Additionally, poor emissions can happen due to the failure in controlling the emissions system, so if your PCM is not functioning correctly, you should replace it as soon as possible.
9. Engine Control Module - Your car might not start, especially after ensuring that the battery and starter are performing correctly. If your car's problems taper down to a defective engine control module, you should replace it as right away to stop whatever serious risks hinders the performance of your car.
10. Wastegate - If too much exhaust gas is sent through the turbine, the unit can accelerate in speed, posing mechanical stress on it and can lead to a variety of problems, for instance fragmented shafts, faulty compressor wheels, or a powerful burst to the engine's internals and power delivery. It’s acceptable to adjust the turbo on its own and replace a high-end model with one designated for the job.

Symptoms that are compatible with a defective throttle position sensor include: Pausing or staggering upon speed capacity, wobbly idle, and a brightened check engine light. In other cases, a result might even be a no-start condition.

Common Symptoms

• Rough or low idle
• Stalling
• Surging
• No/little acceleration
• Other symptoms may also be present

The powertrain control module (PCM) provides a 5 Volt reference signal to the throttle position sensor (TPS) and normally it’s at a ground as well. A general correction is as follows:

• If having a scan tool to access, see what functionality the idle and WOT (wide open throttle) readings bring for the TPS. Detect if they're close to the identifications brought up from above. If not the case, then replace the TPS and re-examine.
• Detect for an irregular open or short voltage within the TPS signal. To achieve this, you should not use a scan tool. What you'll need is an oscilloscope. The reason this occurs is because scan tools take up samples of many different readings just over one or two data lines and can miss an irregular drop out. It is best to hook up the oscilloscope and watch for the signal. It should brush up and down nicely without dropouts or spikes.
• If you don’t notice problems, then carry out a wiggle test. You can achieve this by wiggling the connector and harness as you watch the pattern. Does it successfully drop out? If does so, exchange TPS and re-detect.
• If you don’t have a TPS signal, then check at the connector for 5 Volt references. If presently in view, detect the ground circuit for open or shorts.
• Ensure that the signal circuit is not 12V. It shouldn’t ever have battery voltage. If so, trace the circuit for short to voltage and fix.
• View for any trace of water in the connector and exchange TPS as needed.

It’s wise to always check diagnostic scanner in advance for your particular car. You may have an issue with your engine that can easily be sought out by the repairman to fix that can save you the expense during this diagnosis.

• Reading and recording the codes retrieved and observing the freeze frame data to see when the P0122 code was set.
• Erasing the OBD-II error codes and re-examining the car to see if the P0122 code returns.
• Looking to detect all TPS connections and wiring for any loose or damaged items.
• Collating the data between TPS circuit A and B on the scanner and if not correct, executing the TPS pinpoint tests as for each of the manufacturer's proposals.

Common Mistakes When Diagnosing The P0122 Code

• A visual inspection is not conducted first
• Codes are not red, recorded, clearing or re-examined to confirm errors
• Exchanging a TPS sensor before tests detect an issue
• Distinguishing TPS sensor A and B qualifications are not made before and after repair or replacements