Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMERCURY2010MARINER HYBRID, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1380 (ENGINE CONTROLS - POWERTRAIN DTC CHARTS AND DESCRIPTIONS (HYBRID))DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONSDTC P1299: CYLINDER HEAD OVER TEMPERATURE PROTECTION ACTIVE
2010 Mercury Mariner Hybrid, AWD
DTC P1299: Cylinder Head Over Temperature Protection Active
2010 Mercury Mariner Hybrid, AWDSECTION DTC P1299: Cylinder Head Over Temperature Protection Active
WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, 2011 Ford Fusion, 2010 Mercury Milan, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
P1299 - CYLINDER HEAD OVER TEMPERATURE PROTECTION ACTIVE
| Description: | Indicates an engine overheat condition was detected by the cylinder head temperature (CHT) sensor. An failure mode effect management (FMEM) strategy called fail-safe cooling was activated to cool the engine. | ||
| Possible Causes: |
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| Diagnostic Aids: | Refer to POWERTRAIN CONTROL SOFTWARE , for more information on the fail-safe cooling strategy and the CHT sensor. | ||
| Application | Key On Engine Off | Key On Engine Running | Continuous Memory |
| All | GO to PINPOINT TEST DL . | ||
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.