Guide To P0120 OBD Error Code Solutions

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The P0120 generic code can be defined as the throttle pedal position sensor/switch “A” circuit malfunction. It is a trouble code which indicates that the engine control module has seen the TPS sensor circuit A output voltage going below or above the sensor’s expected range, or is chattering when compared to TPS sensor circuit B.

It is the throttle position sensor which would respond to the accelerator pedal movement. This sensor is a potentiometer which transforms the throttle position into output voltage and emits the voltage signal to the engine control module. In addition to that, the sensor would detect the opening and closing speed of the throttle valve and would feed the voltage signal to the engine control module.

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

• The throttle return spring might be sticking
• There can be corrosion in the MAP or TPS connector
• Misrouted harness may start causing chafing
• There can be some defects in the TPS
• Issues with the powertrain control module

1. Boost Pressure Sensor - Everything is okay with the timing chain and still OBD code P0120 triggering? Then there must be some defects in Boost pressure sensor. Replace them as soon as possible.
2. Turbocharger - P0120 code flashing? Get your Turbocharger inspected from a mechanic.
3. Supercharger - Supercharger is an important auto part. Take care of it and you can rely on us to purchase best quality Supercharger online.
4. Knock Sensor - There can be some defects in the Knock Sensor due to which P0120 code may come on again and again. Make sure to replace it or else you may have to face some major issues.
5. Spark Plug - Are you facing OBD Error Code P0120? Don’t worry as you can fix this issue with new Spark Plug. We care for our customers, that’s why we have Spark Plug for every make and model.
6. Intake Manifold - A broken Intake Manifold can cause a lot of issues. It would be nice if you get it replaced on time.
7. Boost Pressure Gauge - OBD Code P0120 can appear because of Boost Pressure Gauge.
8. Powertrain Control Module - There can be some issues with the PCM due to which you may see P0120 code appearing over and over again. Visit us to buy best quality PCM online.
9. Engine Control Module - Are you facing some faults in your Engine Control Module? Don’t worry and get them replaced or else P0120 code can turn up.

You might be thinking that how would you diagnose these problems? We at Parts Avatar Canada would help you diagnose the major symptoms easily.

Common Symptoms

• The malfunction indicator lamp may start illuminating
• There can be an issue of misfiring at idle or at highway speed
• There can be a bad idle quality

• The MAP or TPS connector should be first tested and replaced
• The boost pressure sensor should be repaired or replaced
• You must repair or replace an open wire or short as needed
• You can always replace the engine control module if shorted out 

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• A variable output voltage reading is received by the powertrain control module from the throttle position sensor
• The output signal would help the powertrain control module to determine the degree which the throttle body has been opened in order to achieve the desired RPM level
• The throttle position sensors are of the non-contact variety are the most modern ones and include hall effect sensors, magnet resistive style sensors, and inductive sensors. Several tools will prove instrumental in successfully diagnosing the condition which caused this code
• You must use a scanner, a digital volt/ohmmeter, an oscilloscope, and a manufacturer's service manual as they will all be very helpful. You can always begin your diagnosis by visually inspecting all wiring as well as connectors
• Then you must look for shorted or burned wiring and replace circuitry and connectors as required
• If you find out that the system wiring, connectors, and components appear to be in normal working order, then you should connect the scanner to the diagnostic connector and record all stored trouble codes and freeze frame data
• This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
• Now once the codes are cleared, you should operate the vehicle to see if the code returns
• If you find out that the code has failed to immediately return, then you may have an intermittent condition
• Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made. If you want to test the throttle position sensor output voltage, measure the signal voltage reading at the connector face as you manually activate the throttle body
• Carefully watch for sudden jumps in voltage or glitches as the voltage drops
• Throttle position sensor adjustment is also critical to proper operation
• If the throttle position sensor checks out, then you must disconnect the connector from the throttle position sensor and any related controllers
• A continuity and resistance test should be performed on all related circuits and repair or replace open or shorted circuits as required
• All the codes should be cleared up and test drive the vehicle to ensure that the repair has been successful. Should all system circuitry and the throttle position sensor prove to be within acceptable specifications, suspect a defective PCM
• You must keep in mind that powertrain control module failure is rare and replacement of such will require reprogramming 

Common Mistakes When Diagnosing The P0120 Code

• There can be a faulty throttle/pedal position sensor or switch
• The throttle bore can be dirty or carbon-filled
• The floor mats might be torned or jammed
• Faulty or corroded throttle/pedal position sensor/switch wiring or connections