P0218 OBD-II Trouble Code: Transmission Over Temperature

P0218 trouble code definition

Transmission over temperature condition

What the P0218 code means

The P0218 code means that the transmission temperature has exceeded the maximum allowable limit that has been set by the vehicle’s manufacturer.

What are the causes of the P0218 code?

• A leak from any part of the transmission system such as the transmission pan, transmission cooler lines, transmission cooler, or the radiator.

• Internal damage to the transmission causing excess friction between internal moving transmission parts.

• A faulty transmission temperature sensor

• A faulty powertrain control module

• It is even possible that the engine being overheated could cause the transmission to overheat as well.

Note: Vehicles will either have a transmission cooler or radiator but usually not both.

What are the symptoms of the P0218 code?

Symptoms of the P0218 code may include an improperly operating transmission in ways such as slipping, hard shifts, or total lack of response all together.

Some vehicles have a fail-safe mode built into their transmissions to assist the driver in getting to a safe place to pull over before shutting off the vehicle. If the vehicle in question has a fail-safe system integrated, this feature may be engaged as an additional symptom.

How does a mechanic diagnose the P0218 code?

A mechanic would start diagnosing the P0218 code by checking the transmission fluid level and condition. If the transmission fluid is low or smells burnt, the transmission may have some internal damage.

Next, the mechanic would inspect the transmission and its cooling system for any leaks of transmission fluid. If a leak is found during this inspection, this may be another cause of the overheating issue. Any leak that is found should be repaired and the transmission should be topped off before any further diagnosis takes place. If the fluid level is low, the transmission fluid that is left will start to burn so just because it smells burned does not guarantee that the transmission has internal damage. If no leaks were found but fluid smells burnt, this would be a good reason to suspect the transmission may have internal damage.

If neither of these conditions are found, the mechanic would then test the transmission temperature sensor for proper function and if it were faulty it would then be replaced. If the transmission temperature sensor proves to be functional, the issue may lie within the powertrain control module.

Common mistakes when diagnosing the P0218 code

• A common mistake that could be made when diagnosing the P0218 code would be finding one problem and stopping the diagnosis at that point.

• A leaking transmission is one problem, but this problem may have caused the fluid level to go low and therefore may have internal transmission damage.

• It is important to inspect all aspects of a problem before calling the repair complete.

  • It is possible that a transmission fluid leak could be repaired and the same P0218 code could come back.

How serious is the P0218 code?

A P0218 code would be considered very serious as it relates to one of the most expensive parts of an automobile. A transmission replacement for most vehicles could cost thousands of dollars. It is very important to have this issue diagnosed and repaired immediately in order to save the transmission from major damage.

What repairs can fix the P0218 code?

• Repairing a transmission fluid leak by replacing parts such as the radiator, transmission cooler, transmission cooler lines, or transmission pan gasket.
• Replacing the transmission temperature sensor
• Replacing the powertrain control module
• Rebuilding or replacing the entire transmission
• Repairing an engine overheating condition

Additional comments regarding the P0218 code?

In order to help avoid getting a P0218 code, it is always a good idea to check your transmission fluid at least at every oil change. It is also important to have the transmission fluid and filter (if applicable) replaced at regular intervals to keep the transmission in good working order.

Need help with a P0218 code?

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