P0122CriticalThrottle (TPS) & Air (MAP) • Bike, Car, Auto
Throttle Position Sensor (TPS) Circuit Low Input
थ्रॉटल पोजीशन सेंसर (TPS) सर्किट वोल्टेज कम — common code demo from the VahanScan app’s full offline DTC library.
Multimeter Testing Specifications & Pinouts
- Power Pin (VCC)
- 5.0V ± 0.15V DC from ECU Reference Output
- Signal Pin
- Closed Throttle: 0.5V – 0.7V | Wide Open Throttle: 4.2V – 4.7V
- Ground Pin Continuity
- Sensor Ground to ECU (< 0.3 Ω)
- Coil / Heater Resistance
- TPS Resistance: 1.2 kΩ – 2.8 kΩ across pins 1 & 3
💡 Voltage must rise smoothly without any dead spots or erratic jumping.
Fault Symptoms
- •Engine does not accelerate when twisting throttle / pressing pedal
- •Stuck at idle speed (Limp home mode 1500 RPM)
- •Violent surging or unexpected throttle cut-off
- •Hard start and high fuel consumption
लक्षण
- •एक्सेलरेटर मरोड़ने पर बाइक/गाड़ी का रेस न पकड़ना
- •इंजन 1500 आरपीएम पर अटक जाना (लिम्प मोड)
- •चलते-चलते अचानक रेस कट जाना या झटका लगना
- •स्टार्टिंग में दिक्कत और ज्यादा तेल पीना
Probable Causes
- •TPS internal carbon potentiometer track worn out
- •5V ECU reference voltage line broken or shorted to ground
- •Water entered throttle body 3-pin / 6-pin connector
- •Throttle cable adjusted too loose or throttle butterfly stuck
संभावित कारण
- •TPS सेंसर के अंदर की रेजिस्टेंस पट्टी घिस जाना
- •ECU से आने वाली 5V सप्लाई की तार कट जाना या अर्थ हो जाना
- •थ्रॉटल बॉडी के कपलर में पानी या जंग घुसना
- •थ्रॉटल केबल ढीली होना या बटरफ्लाई वाल्व जाम होना
Step-by-Step Repair Guide
- 1.1. Disconnect TPS 3-pin connector. Turn Ignition ON.
- 2.2. Multimeter 20V DC: Measure Pin 1 (VCC) — must be exactly 4.85V to 5.15V.
- 3.3. Measure Pin 2 (Signal): Throttle closed = 0.5V to 0.7V. Slowly rotate throttle to full open — voltage must smoothly rise to 4.2V - 4.6V without any drops.
- 4.4. Measure Ground Pin continuity to frame (< 0.3 Ω).
- 5.5. If voltage drops to 0V while rotating, replace TPS sensor and calibrate with VahanScan.
Physical Sensor Location: Mounted on the side of the throttle body assembly shaft.
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