Fault code P0218 is called “Transmission Over Temperature Condition” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P0218
This diagnostic trouble code (DTC) is a generic transmission code. Error P0218 is considered a general code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly from model to model.
Before operation, most of the transmission fluid is in the sump. It passes through the filter and control valve housing assembly as it begins to run. Before it enters the transmission crankcase and finally the oil pump assembly.
The fluid is pressurized in the oil pump assembly, from where it travels to the pressure regulator valve. Here it lubricates the hydraulic circuits of the transmission and other various components.
Hot fluid exits the torque converter and flows into the transmission cooler lines. Passing through the torque converter clutch engagement valve and the oil cooler itself. The cold fluid then returns to the front of the transmission to lubricate and remove heat from it.
If you keep a P0218 code, it means that the transmission fluid temperature, has exceeded the allowable limit. Normally, the temperature should exceed 284°F for an extended period of time.
It is worth considering that high transmission fluid temperatures are a major factor in transmission failure.
Symptoms of vehicle malfunctions
The main signal that an error P0218 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be recorded in the memory as a fault).
- The vehicle’s transmission does not engage.
- The vehicle starts in 2nd or 3rd gear (emergency mode).
- Unable to shift gears.
- Transmission shifts hard or slips.
- Fluid leaking from torque converter seal or other location.
- Low fluid level in transmission.
- Transmission overheating.
- Problems with engagement and disengagement of the torque converter lockup clutch.
- Increased fuel consumption.
The severity level of error P0218 is quite high, so it is recommended to eliminate the problem as soon as possible. Because ignoring the problem for a long time can lead to more extensive and costly repairs. Over time, the performance of the vehicle may decrease so much that it simply cannot be driven.
Factors that can cause this error code
The error code P0218 can mean that one or more of the following problems have occurred:
- Possible short to ground in the transmission fluid temperature sensor signal circuit.
- Probability of TFT sensor failure (internal short circuit).
- Contamination or low level of ATF transmission fluid.
- Clogged or clogged transmission fluid passages.
- A leak in the power transmission system, which may indicate a faulty or damaged transmission pan.
- Cooling fan/fan clutch not working.
- Mechanical failure inside the transmission.
- Overheating due to towing an overloaded trailer.
- Sometimes the cause is a faulty transmission control module.
How to fix or reset OBD-2 code P0218
Some suggested steps for troubleshooting and fix the error code P0218:
- Change ATF fluid and filter.
- Fill transmission fluid to required level.
- Flushing to clean inside channels of transmission.
- Testing, if necessary replacing faulty transmission fluid temperature sensor.
- Troubleshooting mechanical problems inside the transmission.
- Checking connectors as well as wiring.
- Flashing or replacing the transmission control module.
Diagnose and repair of problems
Always check the technical service bulletins (TSB) for your particular vehicle first. The P0218 problem may already be a known problem with a known fix issued by the manufacturer. This can save you time and money during diagnosis.
The next step is to locate the transmission fluid temperature (TFT) sensor. Once found, visually inspect the connector and wiring. Look for scratches, scuffs, exposed wires, burn stains, or melted plastic.
Disconnect the connector and carefully inspect the terminals inside the connector. See if they look burnt or have a green tint indicating corrosion. If you need to clean the terminals, use an electrical contact cleaner and a plastic-bristle brush. Allow to dry and apply electrical grease to the contact areas of the terminals.
Using a diagnostic tool, clear the trouble codes from the memory and see if the P0218 error returns. If the code returns, we will need to test the TFT sensor and associated circuits.
Wiring test
With the ignition key off, disconnect the electrical connector on the TFT sensor. Connect a digital voltmeter. The black wire to ground and the red wire to the signal terminal on the TFT sensor wiring harness connector.
Turn on the ignition key. Depending on the manufacturer’s specifications, the voltmeter should show either 12 volts or 5 volts. Jerk the connection and see if the reading changes. If the voltage is incorrect, replace the faulty wires or connector.
Check the sensor
Connect one ohmmeter wire to the signal terminal on the TFT sensor, and the other to ground. Check the resistance against the manufacturer’s specifications. Jiggle the connector on the transmission fluid temperature sensor, checking the resistance. If the ohmmeter reading differs from the manufacturer’s recommendation, replace the TFT sensor.
If the wiring and sensor tests are done, but you keep getting a P0218 code. You need to look at the PCM / TCM module as well as internal transmission failures. But you need to do this after replacing the TFT sensor. More often than not, it is the one that is the problem.
If you are unsure, get help from a qualified automotive diagnostician.
On which vehicles does this problem occur most frequently
Fault code P0218 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Chrysler (PT Cruiser, Sebring)
- Dodge (Caliber)
- Ford
- Jeep (Grand Cherokee, Liberty, Wrangler)
- Mazda
- Nissan
- Opel
- Ssangyong
Fault code P0218 can sometimes be found with other errors. The most common are the following: P0031, P0037, P0158, P0173, P0714, P0741, P0776, P1684, P2181, P2187, P2503.
