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An intermittent TPS can put you in limp mode without warning. Watch the TPS percentage live data while slowly pressing the pedal - a clean sweep should be perfectly linear with no flatspots or spikes. See throttle body cleaner on Amazon ↗
🗺️ Where Is the Problem?
Blueprint view - P0124 fault zone in the engine and emissions control system
These are statistical causes across ALL vehicles - your exact car may rank differently
For example, on a Honda 4-cyl the downstream O2 sensor causes P0124 64% of the time, but on a GM 5.3L V8 the catalytic converter is the cause 71% of the time. Get a probability ranking built specifically for your year, make, model, and mileage.
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🎯 Top Causes & Probability
50%
#1 - Most Likely
Worn TPS / Throttle Body
On older mechanical-link throttle bodies, the carbon track inside the TPS develops dead spots. On drive-by-wire throttles, the entire throttle body assembly often needs replacement.
🔧 Part
$50–$300
👨🔧 Labor
$60–$140
⚡ DIY Difficulty
Medium
30%
#2 - Check First
Connector or Wiring Fault
The TPS connector at the throttle body sees heat and vibration. Look for back-out pins, broken locking tabs, or chafed wires. A wiggle test reveals the issue quickly.
🔧 Part
$10–$40
👨🔧 Labor
$40–$120
⚡ DIY Difficulty
Easy
15%
#3 - Less Common
Carbon Buildup on Throttle Plate
Heavy carbon on the throttle plate makes idle position uncertain, which can flag the TPS as intermittent. Cleaning the throttle body and relearning idle often resolves it.
🔧 Part
$10–$30
👨🔧 Labor
$60–$140
⚡ DIY Difficulty
Easy
🚗 Most Affected Vehicles
🔧 Step-by-Step Diagnosis
- Slow-sweep TPS test - With a scan tool on TPS%, slowly press the pedal from 0–100% over 5 seconds. Any flatspot, dropout, or spike pinpoints the bad sensor.
- Wiggle test the connector - Engine idling, flex the TPS pigtail. A jump in TPS% confirms wiring fault.
📍 Find a Trusted Shop Near You
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Tips for Choosing a Shop
- Ask if they charge a diagnostic fee and whether it applies toward the repair
- Request a written estimate before approving any work
- Ask specifically about the part brand - OEM vs. aftermarket matters for this code
- Check Google reviews for recent mentions of the specific repair you need