AutoCodesMercury – P1299 Mercury

P1299 Mercury Code - Cylinder Head Temperature Sensor Detected Engine Overheating Condition

Quick Answer

The Cylinder Head Temperature (CHT) Sensor is a thermistor device in which resistance changes with temperature. Common causes include Low engine coolant, Faulty Thermostat, Faulty Cylinder Head Temperature (CHT) Sensor. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1299 Mercury indicates Cylinder Head Temperature Sensor Detected Engine Overheating Condition.
Common causes
Common causes include Low engine coolant, Faulty Thermostat, Faulty Cylinder Head Temperature (CHT) Sensor.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code Popularity 15,399
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jul 11, 2020
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Code P1299 Mercury Description

The Cylinder Head Temperature (CHT) Sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as temperature increases, and the resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the Powertrain Control Module (PCM) corresponding to temperature.
The CHT sensor is installed in the aluminum cylinder head and measures the metal temperature. The CHT sensor can provide complete engine temperature information and can be used to infer coolant temperature. If the CHT sensor conveys an overheating condition to the PCM, the PCM initiates a fail-safe cooling strategy based on information from the CHT sensor. A cooling system concern such as low coolant or coolant loss could cause an overheating condition. As a result, damage to major engine components could occur. Using both the CHT sensor and fail-safe cooling strategy, the PCM prevents damage by allowing air cooling of the engine and limp home capability.
The Diagnostic Trouble Code (DTC) indicates an engine overheat condition was detected by the Cylinder Head Temperature Sensor. A Failure Mode Effects Management (FMEM) strategy called fail-safe cooling was activated to cool the engine.
OBDII Code P1299 Mercury - Cylinder Head Temperature Sensor Detected Engine Overheating Condition - AutoCodes.com
P1299 Mercury Code - Cylinder Head Temperature Sensor Detected Engine Overheating Condition

What are the Possible Causes of the DTC P1299 Mercury?

  • Low engine coolant
  • Faulty Thermostat
  • Faulty Cylinder Head Temperature (CHT) Sensor
  • Cylinder Head Temperature Sensor harness is open or shorted
  • Cylinder Head Temperature Sensor circuit poor electrical connection

How to Fix the DTC P1299 Mercury?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1299 Mercury code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1299 Mercury Code

No Frequently Asked Questions about P1299 Mercury Code found.

Discuss the causes and fixes for P1299 Mercury OBDII Code

  • Went to Auto zone....Engine light on.They detected a couple codes.... P1299, P0130, P1299, P0130. Auto zone looked at Transmission fluid. Found out that it was empty...Put in 5 gallons of transmission fluid. Than found out there is an leak underneath vehicle.

  • What model and year is your vehicle? Low transmission fluid should not trigger the codes you listed P1299 and P0130.

    P0130 MERCURY - O2 Sensor Circuit Malfunction Bank 1 Sensor 1
    Read more: https://www.autocodes.com/p...

  • 08' Mercury Sable

  • The Engine Cooling Fan is the most likely cause of the P1299 code and the Oxygen sensor for the P0130 code, but neither of the codes are related to the transmission.

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