AutoCodes – Generic – P1285

P1285 Code - Cylinder Head Over Temperature Condition

Quick Answer

The Cylinder Head Temperature (CHT) Sensor is a thermistor device in which resistance changes with temperature. Common causes include Engine overheated, Low engine coolant level, 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: P1285 indicates Cylinder Head Over Temperature Condition.
Common causes: Common causes include Engine overheated, Low engine coolant level, 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 46,441

How popular is this code, among other codes? Medium

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 11, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1285 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 the Cylinder Head Over Temperature Sensed Indicates an engine overheat condition was sensed by the cylinder head temperature sensor.

OBDII Code P1285 - Cylinder Head Over Temperature Condition - AutoCodes.com — P1285 Code - Cylinder Head Over Temperature Condition

What does this mean?

What are the Possible Causes of the DTC P1285?

Engine overheated
Low engine coolant level
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 P1285?

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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1285 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.

Need more information about the P1285 code?

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Need Help with the Code?

Get the P1285 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1285 Audi — Fuel Injection Air Control Valve Circuit Short To Ground
P1285 BMW — Switching Solenoid for Air Assisted Injection Valves Bank 1 Control Circuit Signal High
P1285 Buick — Accelerator Pedal Position Sensor 3 Circuit
P1285 Cadillac — Accelerator Pedal Position Sensor 3 Circuit
P1285 Chevrolet — Accelerator Pedal Position Sensor 3 Circuit
P1285 Chrysler — Fuel Injection Pump Controller Always On
P1285 Dodge — Fuel Injection Pump Controller Always On
P1285 Ford — Cylinder Head Over Temperature Condition
P1285 GMC — Accelerator Pedal Position Sensor 3 Circuit
P1285 Honda — Accelerator Pedal Position Sensor 3 Circuit
P1285 Isuzu — Accelerator Pedal Position Sensor 3 Circuit
P1285 Lincoln — Cylinder Head Over Temperature Condition
P1285 Mazda — Cylinder Head Over Temperature Condition
P1285 Mercury — Cylinder Head Over Temperature Condition
P1285 MINI — Switching Solenoid for Air Assisted Injection Valves Bank 1 Control Circuit Signal High
P1285 Volkswagen — Fuel Injection Air Control Valve Circuit Short To Ground

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 P1285 Code

1. What are the common symptoms of OBDII code P1285 (Cylinder Head Over Temperature Condition)?

- Common symptoms include engine overheating, loss of power, rough idling, and potential engine misfires.

2. What are some possible causes of OBDII code P1285?

- Causes of this code may include a faulty cylinder head temperature sensor, a malfunctioning cooling system, or a problem with the engine control module (ECM).

3. How can I diagnose the issue related to OBDII code P1285?

- To diagnose the issue, you can use an OBDII scanner to retrieve the code, check the cylinder head temperature sensor for proper function, inspect the cooling system for leaks or blockages, and test the ECM for any faults.

4. What should I do if my vehicle displays OBDII code P1285?

- If your vehicle shows this code, it is important to address the issue promptly to prevent potential engine damage. Seek professional assistance to diagnose and repair the underlying problem.

5. Can I continue driving my vehicle with OBDII code P1285?

- It is not recommended to continue driving your vehicle with this code present, as it indicates a critical issue with the cylinder head temperature that can lead to severe engine damage if left unresolved.

6. Are there any DIY repair tips for fixing OBDII code P1285?

- DIY repair tips may include checking and replacing the cylinder head temperature sensor, inspecting the cooling system for leaks or blockages, and ensuring the ECM is functioning correctly.

7. How much does it typically cost to repair OBDII code P1285?

- The cost of repair can vary depending on the specific cause of the issue. It is advisable to consult a mechanic for a proper diagnosis and cost estimate.

8. Can a faulty thermostat cause OBDII code P1285 to appear?

- Yes, a faulty thermostat can potentially cause the engine to overheat, triggering OBDII code P1285. It is important to check the thermostat as part of the diagnostic process.

9. Is OBDII code P1285 a common issue in certain vehicle makes and models?

- This code can be more common in vehicles with older engines or those that have experienced cooling system problems. However, it can occur in any vehicle with a faulty cylinder head temperature sensor.

10. How urgent is it to address OBDII code P1285 once it appears?

- It is crucial to address OBDII code P1285 promptly to prevent further damage to the engine and ensure the vehicle's safe operation.