P0124 code definition
Throttle Pedal Position Sensor/Switch (TPS) A Circuit Intermittent
What the P0124 code means
- P0124 is the generic OBD-II code that indicates the TPS sensor circuit A output voltage goes below or above the sensor's expected range; the signal is erratic and fails intermittently.
What causes the P0124 code?
The TPS circuit A signal is erratic compared to TPS circuit B.
The TPS circuit signal A may be going in and out of specifications of .2 volts or below.
The TPS circuit signal A may be going in and out of high specifications of 4.54 volts.
What are the symptoms of the P0124 code?
The Engine Control Module (ECM) will go in and out of failsafe mode when the sensor goes in and out of specifications.
The ECM will turn the Check Engine Light on and go into a failsafe mode.
The ECM cuts current to the throttle actuator so the throttle valve closes to approximately 6 degrees of throttle plate opening.
The fuel injection and ignition is used to control engine speeds.
The vehicle speed is limited to very slow with limited throttle response.
The engine may idle higher or lower than normal.
Note: The symptoms above are determined by the manufacturer failsafe ECM strategy for the vehicle during a TPS failure and may vary between manufacturers and vehicles.
How does a mechanic diagnose the P0124 code?
Scans and documents the codes received, views the freeze frame data to see the conditions when the code was set to try and duplicate the failure
Clears the OBD-II fault codes and retests the vehicle to see if the code comes back
Checks all TPS connections and wiring for intermittent problems
Compares the data between TPS circuit A and B on the scanner while performing a wiggle test to try and find an intermittent wiring or connector issue
Repairs the wiring or connections as needed
Replaces the TPS, as pinpoint tests dictate, and performs a road test after clearing the codes
Common mistakes when diagnosing the P0124 code
Not visually inspecting for the source of the problem first
Not scanning, documenting, clearing and retesting the codes to verify any failures before attempting any repairs
Replacing the TPS sensor without verifying through tests that there is a problem
Not comparing TPS sensor A and B to be within specification before and after repair or replacements
How serious is the P0124 code?
The P0124 code can cause the engine's ECM to go into and out of failsafe mode, which will cause various drive issues until repairs are done such as lack of acceleration, high idle, bucking or jerking, limited speeds, or stalling, depending on the manufacturer's failsafe mode strategy.
The TPS sensor's failure can also affect other systems and cause them to work erratically, such as the transmission, brakes, and suspension to name a few.
What repairs can fix the P0124 code?
Repairing or replacing the TPS connector open or shorts
Repairing the wiring open or short circuits as necessary
Replacing the TPS with a new sensor
Additional comments for consideration regarding the P0124 code
The P0124 code may be accompanied by other TPS codes, so following the manufacturer pinpoint tests for each code received may be needed to find and fix the failure.
Most failures for code P0124 involve a defective TPS sensor, or sensor connector corrosion or damage.
All TPS codes will cause the ECM to go into failure mode and drive symptoms will be the same for all the TPS codes.
Need help with a P0124 code?
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This article originally appeared on YourMechanic.com as P0124 OBD-II Trouble Code: Throttle Pedal Position Sensor/Switch (TPS) A Circuit Intermittent and was authored by Jay Safford.