P1285Manufacturer-specific code

P1285 Code: Cylinder Head Overtemperature Detected (Ford)

On Ford, Lincoln and Mercury, the P1285 code means cylinder head overtemperature was detected. You will notice a loss of power. Stop driving and let the engine cool before you do anything else.

Severity
Critical
Can I keep driving?
No, stop and have it checked
Estimated cost
$10 to $900
Difficulty
Medium
System
Idle and Speed Control
Applies to
Depends on the manufacturer

Common in: Ford

Updated Reviewed by Renzo Chacca

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What the P1285 code means

P1285 is a manufacturer-specific code: the 1 in the second position means each automaker defines what it stands for, not the generic standard. The most widespread definition is the one used by Ford, Lincoln and Mercury. If your vehicle is another brand, confirm the code text with a scan tool that supports that manufacturer.

ManufacturerMeaning of P1285
Ford, Lincoln and MercuryCylinder head overtemperature detected

Some Ford engines, especially the Zetec, Duratec and Modular, measure the temperature at the cylinder head with the CHT sensor instead of, or in addition to, the coolant temperature. If they detect overheating, they turn on a protection mode that shuts off cylinders.

The computer sets the P1285 code when the CHT sensor reports an excessive cylinder head temperature. It is a serious warning: look for low coolant, a thermostat problem or a fan problem.

Before you repair anything, confirm the make, model, year and engine. With manufacturer codes, the same number can change even between engines from the same brand.

P1285 code symptoms

  • High temperature gauge.
  • Loss of power.
  • Check engine light on.

Likely causes of the P1285 code

  1. Low coolant level. The most frequent cause.
  2. Stuck thermostat. Confirm it with the tests in the diagnosis section.
  3. Fan not working. Confirm it with the tests in the diagnosis section.
  4. Water pump. Measure its real flow or pressure.
  5. CHT sensor giving a wrong reading.

How to diagnose the P1285 code step by step

  1. Pull over and let the engine cool.
  2. Check the level with the engine cold.
  3. Check the fan and the thermostat.
  4. Compare the CHT reading with a thermometer.

How to fix the P1285 code

  • Refill and bleed the cooling system.
  • Repair the thermostat, the fan or the pump.
  • Replace the CHT sensor if it reads wrong, then clear the P1285 code and watch the temperature on a test drive.

Technical reference data

  • Many Ford engines trigger the protection above about 120 to 130 °C (248 to 266 °F) at the cylinder head.
  • P1xxx codes are manufacturer-specific: confirm the definition with a scan tool that supports your brand.
  • Values are approximate: check the manufacturer data for your vehicle.

Brand-specific notes

Common on the Focus, Fiesta, Escape, Explorer, Ranger, F-150 and Mustang.

If your vehicle is another brand, check the table above for the meaning its manufacturer gives the code, and confirm it with a scan tool that supports that brand.

Frequently asked questions about P1285

What does the P1285 code mean on a Ford?
It means the cylinder head is running too hot. You will notice a loss of power as the engine protection kicks in.
Does P1285 mean the same thing on every brand?
No. It is a manufacturer code, and on other brands it may not exist or it may mean something else.
Can I drive with a P1285 code?
No. Pull over, shut the engine off and let it cool. Driving with an overheated cylinder head can warp it or blow the head gasket.
How much does it cost to fix P1285?
On a Ford the cost runs from about $10 to $900. Topping off coolant is cheap, while a water pump, a radiator or head damage costs far more.
Will a P1285 code clear itself?
No. The engine will run hot again until the cause is found, such as low coolant, a stuck thermostat, a dead fan or a bad water pump.
What is the most common cause of P1285?
Low coolant level. Check it once the engine is cold, then look at the thermostat, the fan and the water pump.

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Questions about the P1285 code

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