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P1285 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

P1285 is an OBD-II Code that refers to Cylinder Head Over Temperature Condition

Meaning

A P1285 code is a manufacturer specific diagnostic trouble code that occurs in Ford vehicles when the ECM/PCM detects when the temperature gauge for cylinder head reads temperature that is higher than normal or more than the allowable temperature for the engine to function properly.

Causes

Common causes for this code include:

  • The engine has overheated
  • Engine coolant level is low
  • Bad Cylinder Head Temperature (CHT) Sensor
  • Cylinder Head Temperature Sensor circuit poor electrical connection
  • Cylinder Head Temperature Sensor harness is open or shorted

Symptoms

The symptoms of a P1285 code are:

Diagnosis

To diagnose a P1285 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect the engine for any obvious signs of overheating such as a blown head gasket.
  3. Check the engine coolant level and add coolant if necessary.
  4. Inspect the Cylinder Head Temperature Sensor and connector for any signs of damage or corrosion.
  5. Check the Cylinder Head Temperature Sensor circuit for continuity.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P1285 code:

  • Not thoroughly inspecting all the wiring and connectors for damage.
  • Not checking the engine coolant level.
  • Not testing the Cylinder Head Temperature Sensor for proper operation.

How serious is this?

A P1285 code is a serious code because it can cause the engine to overheat and lead to engine damage. If the code is not diagnosed and repaired in a timely manner, it could result in an engine failure.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Broken or faulty wirings must be repaired or replaced
  • Bad Cylinder Head Temperature Sensor must be replaced
  • Engine coolant level must be filled up
  • Cylinder Head Temperature Sensor circuit needs to be repaired
  • Cylinder Head Temperature Sensor harness needs to be replaced

Related codes

A P1285 is related to and may be accompanied by the following codes:

P1285 – Cylinder Head Over Temperature Condition

P1286 – Cylinder Head Thermostat Rationality Check

P1287 – Cylinder Head Temperature (CHT) Sensor Out of Self-Test Range

P1288 – Cylinder Head Temperature (CHT) Sensor Circuit Short to Battery

Conclusion

In conclusion, the P1285 code is a diagnostic trouble code that refers to a problem with the cylinder head temperature sensor or the circuit. This code is a serious code that can lead to engine damage if it is not diagnosed and repaired in a timely manner. The most common cause for this code is an overheated engine, but it can also be caused by a low engine coolant level, a bad Cylinder Head Temperature Sensor, or a problem with the Cylinder Head Temperature Sensor circuit. If you have this code, it is important to have it diagnosed and repaired as soon as possible to avoid further engine damage.