MazicBay Diagnostics
MAZICBAYDiagnostics
FTC Reader Disclosure: When you purchase or register through links on our site, we may earn an affiliate commission at no extra cost to you. Read our Editorial & Advertising Policy.

P0125 on Tesla Model X

Insufficient Coolant Temp for Closed Loop Fuel Control

Factory diagnostic protocol and troubleshooting wire for fault code P0125 specifically for the Tesla Model X (2020–2026, Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors)).

Verified OEM Telemetry & Field Repair Tree
Tesla Model X2020–2026
Tesla Model X
EVDual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Model X SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Medium urgency level
Est. Repair Cost
$120 - $350 (DIY: $30 - $90)
Parts & Labor DIY
Check P0125 On Another Tesla Model:
Diagnose P0125 on Specific Model X Model Year:

1. Symptoms of P0125 on Tesla Model X

When the Engine Control Module (ECM/PCM) on your Tesla Model X (Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors)) logs fault code P0125, drivers commonly observe:

Check Engine Light on on Tesla Model X (Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors))
Engine temperature gauge needle stays low / never reaches center on Tesla Model X (Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors))
Cabin heater blows lukewarm air in cold weather on Tesla Model X (Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors))
Excessive fuel consumption and carbon deposits on tailpipe on Tesla Model X (Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors))
Tesla Model X OBD-II Port Location
The 16-pin diagnostic connector is located Driver side lower instrument panel trim. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Tesla Model X

Historical warranty claims and technical repair bulletins for Tesla Model X point to the following failure distribution:

55%
Thermostat stuck open or opening prematurely (Tesla OEM Part)
25%
Low engine coolant level / air pocket around ECT sensor (Tesla OEM Part)
12%
Failing Engine Coolant Temperature (ECT) sensor (Tesla OEM Part)
8%
Defective upstream Oxygen / Air-Fuel sensor heater circuit (Tesla OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Tesla Model X.

3. Step-by-Step DIY Repair Guide for Tesla Model X

01
Inspect Coolant Level in Radiator and Overflow Tank

Check that engine coolant is at full mark and no external radiator or hose leaks exist. on the Tesla Model X equipped with Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors).

Required Tool: Flashlight
02
Monitor Warm-up Curve with Live Data

Start cold engine and watch ECT climb. If it plateaus below 170°F (77°C) while driving, thermostat is stuck open. on the Tesla Model X equipped with Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors).

Required Tool: OBD-II Scanner
03
Replace Engine Thermostat and Gasket

Drain 1 gallon of coolant, remove thermostat housing bolts, install new OEM temperature-rated thermostat (typically 180°F–195°F) with jiggle valve at 12 o'clock. on the Tesla Model X equipped with Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors).

Required Tool: 10mm/12mm Sockets, Drain Pan, Gasket Scraper
04
Refill and Burp Cooling System

Fill cooling system with 50/50 prediluted coolant, run engine with spill-free funnel to purge air bubbles. on the Tesla Model X equipped with Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors).

Required Tool: Spill-Free Funnel Kit
05
Clear DTCs and Verify Closed Loop Status

Verify scan tool Fuel System Status changes from 'Open Loop' to 'Closed Loop' within 5 minutes. on the Tesla Model X equipped with Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors).

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

Equipment for Diagnosing Tesla Model X (P0125)

Prime Fast Delivery & Verified Fitment
Engine Temperature Control

OEM Thermostat & Gasket Assembly

4.7 / 5.0 (Verified Fit)

Direct-replacement thermostat calibrated to factory operating temperature for Tesla Model X.

$24 – $48 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 Tesla Model XVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
Find Parts on Amazon
* As an Amazon Associate, MazicBay earns from qualifying purchases. Prices & availability subject to change.

Other Common Fault Codes on Tesla Model X

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Tesla Model X:

4. Tesla Model X P0125 FAQs

What causes code P0125 to trigger on a Tesla Model X?

On the Tesla Model X (Dual Motor AWD / Tri-Motor Plaid (1,020 HP Falcon Wing Doors)), P0125 is most frequently caused by Thermostat stuck open or opening prematurely or Low engine coolant level / air pocket around ECT sensor.

Where is the OBD-II port located on my Tesla Model X?

On the Tesla Model X, the 16-pin DLC diagnostic connector is located Driver side lower instrument panel trim. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Tesla Model X with code P0125?

Yes, for short distances. Fuel economy will drop 15–25% as the engine remains trapped in open-loop enrichment. Given that P0125 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.