P1026 on 2019-2020 Lincoln Nautilus (Standard, Select, Reserve) — Engine Coolant Temperature Sensor 1 / Cylinder Head Temperature Sensor 2 Correlation
1 vehicles · 1 makes · $600-$9,000 repair
Most Reported On
P1026 is an OBD-II diagnostic trouble code meaning “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. This code is most commonly reported on 2019-2020 Lincoln Nautilus (Standard, Select, Reserve), with repair costs ranging from $600 to $9,000.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
P1026 does not use the standard P/B/C/U prefix. It may be a manufacturer-specific code, so verify that a scanner supports your exact year, model and module before buying.
FAQ
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 for P1026 range from $600 to $9,000, depending on the vehicle and root cause.
Which vehicles are affected by P1026?
Au7o has documented P1026 across 1 vehicle models from 1 manufacturers: Lincoln.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.