The OBD2 code P0124 signals an intermittent issue with the Throttle Position Sensor (TPS) Circuit A. This sensor plays a crucial role by informing the vehicle’s engine control module (ECM) about the position of the throttle, which in turn affects fuel injection, ignition timing, and other critical engine functions.
An intermittent fault in the TPS can lead to erratic engine behavior, such as sputtering, hesitation, and irregular idling, as the ECM receives inconsistent signals regarding throttle position.
P0124 quick overview
| Meaning | P0124: Throttle Position Sensor/Switch A Circuit Intermittent |
| Is it serious? | Yes, this code can cause unpredictable engine performance and should be addressed promptly. |
| Possible causes | – Faulty or loose Throttle Position Sensor – Corroded or damaged TPS connector or wiring – Poor ground connection or shorts in the sensor circuit – Faulty Engine Control Module (ECM) or Powertrain Control Module (PCM) |
| How to diagnose? | Inspect the TPS and its connector for damage, corrosion, or looseness. Check the wiring and harness for shorts, breaks, or abrasions. Measure voltage and ground at the TPS to confirm proper electrical signals. Test the continuity and resistance in the TPS circuit to identify intermittent faults. Evaluate other components on the same circuit, such as the oxygen sensor and oil pressure switch, for potential related issues. |
P0124 Meaning
Think of the TPS as a communicator between your foot on the gas pedal and the car’s computer, telling it how much power to give the engine. When the P0124 code pops up, it means this communication isn’t consistent, causing the car to act unpredictably.
This could be as noticeable as the car stalling or hesitating when you try to accelerate. Fixing this problem often involves looking at the sensor itself, the wires connected to it, and making sure they’re all in good shape and securely connected.
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How to fix P0124 – learn from mechanics
I looked into P0124 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Dodge P0124
Vehicle Information 2003 Dodge Durango SLT 4.7L
Issue + Repair History
- Vehicle brought in for sputter and hesitation
- Initial diagnosis found fuel pressure at 42 psi, replaced fuel module, pressure increased to 55 psi
- MIL came on during test drive, revealed DTC P0700 referring to transmission codes
- Under transmission codes, DTC P0124 (TPS sensor intermittent) appeared
- Continuity and resistance of all sensor connectors checked, no fluctuation observed in TPS signal
- Replaced TPS sensor, followed by oil pressure switch replacement due to subsequent DTC P0522
- Gearshift test conducted with DRBIII yielded no definitive answers
Other OBD2 Codes + Test Results
- Fuel pressure check: 42 psi initially, increased to 55 psi after fuel module replacement
- DTC P0700 found after fuel pump replacement, referred to transmission codes
- DTC P0124: TPS intermittent
- All sensors on the same circuit checked for resistance
Mechanic Suggestions
- Check voltage output of TPS sensor for smooth operation
- Examine wiring diagrams to identify shared connections between TPS and oil pressure sensor
- Ensure proper connections by inspecting PCM/TCM harness connections under the hood
- Investigate potential shorts to ground on the 5V supply line that could affect sensor readings
Final Fix
- Replaced oxygen sensor before catalytic converter (B1S1) which was feeding false data to the TCM, causing erroneous feedback
- Cleared DTCs P0700, P0124, & P0613
- Discovered ground in oxygen sensor also affecting transmission temp sensor internally, leading to additional issues
Case #2: Chevrolet P0124
Vehicle Information 1996 Chevrolet Cavalier 2.2L
Issue + Repair History
- Historical code indicates a problem with TPS (Throttle Position Sensor)
- Current scan with MT2500 scanner shows TPS voltage fluctuating from 0.18 to 0.63 volts at idle
- TPS recently replaced by a different mechanic
- Vantage scan reveals a significant AC voltage superimposed on the TPS output signal
- Clean Vref at 5.03 volts, clean signal ground at 0.03 volts
- Alternator output shows slight AC voltage (~0.33 volts at idle), insufficient to cause TPS voltage fluctuations
- Visual inspection of wiring harness reveals no abnormalities
- Previous service limited to routine maintenance
Other OBD2 Codes + Test Results
- No current codes present
- Historical code: P0124 (TPS)
Mechanic Suggestions
- Consider checking for moisture intrusion at the PCM (Powertrain Control Module), particularly if the vehicle has been exposed to sand or other debris
- Inspect PCM, located inside the front right quarter panel, for signs of moisture or damage
- Disconnect harness, clean connections thoroughly, and reinstall to eliminate any potential issues caused by moisture or debris
Final Fix
- Discovered moisture at the PCM due to sand infiltration, likely from off-road driving
- Removed panels for access, disconnected harness, and thoroughly cleaned components
- Reinstalled components and ensured a secure connection
- Issue resolved, no recurrence observed after fix
Case #3: Dodge P0124
Vehicle Information 2005 Dodge Caravan SXT 3.3L
Issue + Repair History
- Initial issue: Intermittent EGR code P0406
- Replaced EGR valve twice with OEM parts, code persists intermittently
- Discovered additional TPS code P0124 (intermittent)
- Replaced TPS twice, no change observed
- PCM replaced and reprogrammed by dealer, P0406 and new code P2074 (MAP/TPS correlation) appear
- All connectors checked for corrosion, found clean
- Various clearing procedures attempted without success
- Further testing revealed intermittent 0 TPS volts on engine side, not on transmission side
- Suspected PCM fault, replaced by dealer, issue persists
- No apparent wiring harness abnormalities found upon visual inspection
Other OBD2 Codes + Test Results
- P0406: EGR position sensor high
- P0124: TPS intermittent
- P2074: MAP/TPS correlation
Mechanic Suggestions
- Check wiring behind EGR valve connector for breaks or damage, and verify voltage while wiggling wires
- Load test grounds while voltage drop testing to ensure proper grounding
- Inspect wiring behind intake and around back corner of the head for chafing or damage
- Verify pin fit in connectors, ensuring proper connection
- Inspect wiring harness for chafing, particularly near the rear valve cover
- Disconnect MAP sensor to check if other codes persist, as a faulty MAP sensor could short the 5V circuit and trigger erroneous codes
- Consider the specific parameters for EGR valve operation and verify if the valve is opening at the correct times
- Investigate potential issues with the MAP sensor, as it may cause a short in the 5V reference circuit, triggering multiple sensor codes
Final Fix
- Discovered an intermittent voltage drop on the negative cable where it was crimped onto the battery cable end
- Repaired the voltage drop issue
- Cleared codes and observed no recurrence
- Vehicle runs noticeably better after repair
How to diagnose P0124
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Brief Explanation |
|---|---|
| Inspect TPS and connector | Check for physical damage, corrosion, or looseness that could interfere with signal transmission. |
| Check wiring and harness | Look for damage or wear in the wiring that could cause intermittent connections. |
| Measure voltage and ground | Ensure the TPS is receiving the correct voltage and has a proper ground connection. |
| Test circuit continuity | Use a multimeter to check for intermittent breaks or shorts that could disrupt the sensor’s signal. |
| Evaluate related components | Consider the condition of other sensors and the ECM/PCM, as issues here can also trigger a P0124 code. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko