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 P0727: ENGINE SPEED INPUT CIRCUIT NO SIGNAL
2010 Mercury Mariner Hybrid, AWD
DTC P0727: Engine Speed Input Circuit No Signal
2010 Mercury Mariner Hybrid, AWDSECTION DTC P0727: Engine Speed Input Circuit No Signal
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.
P0727 - ENGINE SPEED INPUT CIRCUIT NO SIGNAL
| Description: | The transaxle control module (TCM) continuously monitors the clean tachometer output (CTO) circuit from the powertrain control module (PCM) for an engine speed signal. This DTC is set when if there is a CTO circuit concern. | ||
| Possible Causes: |
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| Diagnostic Aids: | The TCM parameter identification (PID) ENGCTO should correspond to actual engine speed. If the PID displays 0 RPM when the engine is running, it indicates a CTO circuit concern. | ||
| Application | Key On Engine Off | Key On Engine Running | Continuous Memory |
| Vehicles that start | GO to PINPOINT TEST JH . | ||
| Vehicles that do not start | GO to PINPOINT TEST JD . | ||
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.