P1026 on 2019-2020 Lincoln Nautilus — Engine Coolant Temperature Sensor 1 / Cylinder Head Temperature Sensor 2 Correlation
1 vehicles · 1 makes
How to diagnose and fix P1026: most-reported vehicles
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Lincoln Nautilus · 2019–2020
Some 2.0L EcoBoost Nautilus SUVs may show low coolant, white smoke from the tailpipe, an over-temperature warning, an external coolant leak and/or a check-engine light with stored codes. Ford attributes this to the exhaust gas recirculation (EGR) cooler and/or PCM software settings. It affects 2019–2020 Lincoln Nautilus with the 2.0L EcoBoost engine; bulletin 20-2234 also covers the 2019–2020 Ford Edge 2.0L.
Common Symptoms
- Low coolant level
- White smoke from the tailpipe
- Over-temperature warning
- External coolant leak
- Check-engine light
How to Fix
Have a dealer confirm the symptoms and codes. Bulletin 20-2234 has vehicles built on or before 9-Jul-2020 get the latest PCM software first, then a cooling-system pressure test and inspection of the EGR cooler for damage or internal leaks; if the EGR cooler leaks, the EGR cooler and EGR outlet tube are replaced. If the cooler does not leak, the technician follows standard workshop-manual diagnosis. Normal warranty rules apply; this is not a recall or a promise of free repair.
Sources for this issue (2)
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P1026 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1026 mean?
P1026 stands for "Engine Coolant Temperature Sensor 1 / Cylinder Head Temperature Sensor 2 Correlation." The PCM cross-checks the engine coolant temperature (ECT) sensor against the cylinder head temperature (CHT) sensor. P1026 sets when the two readings disagree by more than a calibrated amount, meaning one sensor is reading incorrectly or coolant is not actually present at the ECT sensor while the head is heating. Ford TSB 20-2234 lists P1026 among the codes (with P0128, P0217, P044C, P1285, P1299, P139A, P2457) stored on 2019-2020 Edge / Lincoln Nautilus 2.0L EcoBoost vehicles suffering coolant loss from a cracked EGR cooler; because the PCM uses this correlation to protect the engine, it will often move into a fail-safe cooling / reduced-power strategy.
What are the most common causes of P1026?
The most common causes of P1026 are: Coolant loss — notably a cracked or leaking EGR cooler on 2.0L EcoBoost (Ford TSB 20-2234), Low coolant level or air trapped in the cooling system so the ECT sensor is not immersed, Failed or drifting ECT or CHT sensor, Damaged ECT / knock-sensor wiring harness (a known 2.7L EcoBoost concern), Outdated PCM calibration (TSB update required), Stuck thermostat or other cooling-system fault causing genuine temperature divergence. The specific cause varies by vehicle.
How much does it cost to fix P1026?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P1026?
Au7o has documented P1026 across 1 vehicle models from 1 manufacturers: Lincoln.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.