P1299

Cylinder Head Overtemperature Protection Active

Car Fault Codes Ford Cooling & lubrication

Can you still drive? No, stop right away

Who can fix it? Needs a workshop

Typical repair time 30 minutes – 6 hours

Typical cost SAR 150 to 3,000

What it means

This is a Ford, Lincoln and Mercury code; the same number can mean something different on other makes. The cylinder head temperature (CHT) sensor recorded a very high temperature, so the engine computer switched to a fail-safe cooling mode that cuts fuel to some cylinders in turn to air-cool the engine. This is a serious warning: stop safely and check the cooling system before driving on.

Models covered: Ford (and Lincoln/Mercury) models with a cylinder head temperature (CHT) sensor (e.g. many 4.6/5.4 V8 and Duratec engines).

Symptoms4

Temperature gauge high or an overheating warning on the dash.
Clear loss of power and shaking as the computer cuts fuel to some cylinders.
Steam or coolant smell from the engine bay at times.
Check engine light on.

Possible causes7

Low coolant from a leaking hose, radiator or water pump.
Thermostat stuck closed.
Failed cooling fan, fan relay or wiring.
Radiator blocked inside or outside.
Failed water pump.
Failed head gasket.
Faulty CHT sensor giving a false high reading (less common).

How to diagnose5

Turn the engine off and let it cool fully; never open the radiator cap when hot.
Check the coolant level and look for visible leaks.
After cooling, run the engine and confirm the fan works and the upper radiator hose gets hot when the thermostat opens.
Compare the CHT reading on a scan tool with the measured engine temperature.
Have the cooling system pressure-tested and the coolant checked for combustion gases if coolant loss repeats.

How to fix5

Repair the leak and refill with the recommended coolant, bleeding air from the system.
Replace the thermostat.
Repair the cooling fan, its relay or wiring.
Replace the radiator or water pump based on the test.
Replace the CHT sensor if proven wrong, then clear the code and monitor temperature while driving.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low for a hose or thermostat, higher for a radiator or water pump, and far above the range if the head gasket or engine was damaged by continued driving.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Why does the engine lose power with P1299?

The computer cuts fuel to some cylinders in turn so they pump air to cool the engine; it is a temporary protection mode to reach a safe place.

Can I finish my trip in fail-safe mode?

Not advised. Fail-safe mode gives a short distance to stop safely, and continuing can damage the head gasket or engine.

Could the sensor be the cause?

It can, but it is less common, so compare its reading with the real temperature before replacing it, and check cooling first.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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