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P0120 on Chevrolet: Symptoms, Causes & Fix

Throttle/Pedal Position Sensor/Switch A Circuit

Official technical diagnostic wire for fault code P0120 specifically affecting Chevrolet vehicles (Silverado, Equinox, Malibu, Tahoe, Traverse).

Sensor Voltage Ref
0.1V – 5.0V Ref
Chevrolet Factory Standard
CAN Bus Speed
500 kbps CAN-FD
ISO 15765-4 Diagnostic Bus
Drivability Status
Not Recommended
Critical urgency level
Est. Repair Cost
$140 - $420
Parts & Labor DIY
Model-Specific Diagnostic Wires

Select Your Chevrolet Model for P0120:

8 Models Available

1. Common Symptoms on Chevrolet Vehicles

When Chevrolet Engine Control Modules (ECM) trigger fault code P0120, drivers typically report:

Check Engine Light and 'Engine Power Reduced' on on Chevrolet Powertrains
Gas pedal does not respond on Chevrolet Powertrains
Rough surging idle on Chevrolet Powertrains

2. Root Causes on Chevrolet Engines

Historical diagnostic claims across Chevrolet engines point to the following failure distribution:

55%
Faulty Throttle Position Sensor (TPS) (Chevrolet OEM Part)
25%
Worn throttle body gears (Chevrolet OEM Part)
12%
Damaged electronic throttle wiring harness (Chevrolet OEM Part)

3. Step-by-Step Fix Protocol for Chevrolet

01
Scan and Record Freeze Frame Telemetry

Connect an OBD-II scan tool and record freeze frame sensor telemetry for code P0120 to note engine RPM, load, and voltage when the fault triggered. on Chevrolet engines.

Required Tool: OBD-II Scanner
02
Inspect Related Wiring Harness & Connectors

Inspect the electrical connector and wiring harness related to P0120 for chafing, corrosion, moisture, or pin push-out. on Chevrolet engines.

Required Tool: Flashlight, Multimeter
03
Test Component Resistance & Voltage Supply

Measure circuit voltage supply (12V B+ or 5V reference) and sensor/actuator resistance according to factory repair manual specifications. on Chevrolet engines.

Required Tool: Digital Multimeter
04
Replace Defective Component

Install a new OEM-grade replacement part, torque fasteners to factory spec, and ensure electrical locking tabs click firmly. on Chevrolet engines.

Required Tool: Hand Tool Socket Set, Torque Wrench
05
Clear Trouble Codes & Complete Drive Cycle

Clear all stored DTCs from vehicle memory and perform an OBD-II drive cycle to confirm the diagnostic monitor resets to 'Ready'. on Chevrolet engines.

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Chevrolet (P0120)

Prime Fast Delivery & Verified Fitment
Variable Valve Timing (VVT)

VVT Oil Control Solenoid Valve

4.6 / 5.0 (Direct Fit)

Restores accurate camshaft timing and oil pressure regulation on Chevrolet.

$34 – $65 Prime
Check Fitment on Amazon
Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

$29.99 Prime
View on Amazon
Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

Compare OEM & Aftermarket Replacement Sensors for ChevroletVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
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4. Chevrolet P0120 Frequently Asked Questions

What does code P0120 mean on a Chevrolet?

On Chevrolet vehicles, P0120 indicates that the Engine Control Module (ECM) detected throttle/pedal position sensor/switch a circuit. This typically points to Faulty Throttle Position Sensor (TPS) or Worn throttle body gears.

Can I continue driving my Chevrolet with code P0120?

No. Throttle response may be disabled or locked in Limp Mode. Because this code carries a Critical severity rating on Chevrolet powertrains, we recommend scanning live data values promptly to prevent secondary damage.

How much does it cost to fix code P0120 on a Chevrolet?

Estimated DIY parts cost ranges from $140 - $420, while professional shop repairs at an authorized Chevrolet dealership or independent specialist typically range from $180 to $380 including diagnostic labor.