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P0123 is a diagnostic trouble code (DTC) for "Throttle Pedal Position Sensor/Switch (TPS) A Circuit High 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. 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.
Throttle Pedal Position Sensor/Switch (TPS) A Circuit High Input
P0123 is the generic OBD-II code which indicates that the Engine Control Module (ECM) has seen the TPS circuit A output voltage go above the sensor's expected voltage specification range.
The Check Engine Light comes on and the ECM goes into failsafe mode by cutting current to the throttle actuator, causing the throttle valve to close to less than 6 degrees of plate opening.
The ECM controls fuel injection and timing to control engine speeds.
The vehicle would be able to be driven very slowly with limited throttle response.
The engine may idle higher than normal and not accelerate as well as before.
Note: The symptoms are determined by the manufacturer failsafe ECM strategy for the vehicle during a failure and may vary between manufacturers and vehicles.
Scans and documents the codes received and views the freeze frame data to see when the code was set
Clears the OBD-II fault codes and re-tests the vehicle to see if the codes come back
Checks TPS connections and wiring for shorted or damaged wiring or connections
Compares the data between TPS circuit A and B on the scanner and if incorrect, performs the TPS pinpoint tests as per the manufacturer's recommendations
Repairs any wiring or connection shorts
Replaces the TPS as pinpoint test dictates, clears the codes, then road tests the vehicle
Not visually inspecting connections and wiring first
Not scanning, documenting and clearing codes, then retesting for them to verify failures
Not verifying and repairing wiring or connector problems after sensor is replaced
Replacing the TPS sensor without making sure it is the problem
Not verifying whether the TPS sensor A and B circuit voltages are within specification before and after repair or replacements.
The P0123 code will cause the engine ECM to go into a failsafe mode, which will cause various drive issues until repairs are done. Depending on manufacturer's failsafe mode strategy, drive issues could include lack of acceleration, high idle, bucking or jerking, limited speeds, or stalling.
Repairing or replacing the TPS connector for shorting
Repairing the wiring short as necessary
Replacing the TPS with a new sensor
The P0123 code may be accompanied by other TPS codes, so following the manufacturer's pinpoint tests for each code received may be needed to find and fix the problem.
Most failures for code P0123 involve a defective TPS sensor, or a connector shorted internally.
All TPS codes will cause the ECM to go into the same failure mode; drive symptoms will be roughly the same.
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