GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2006 🢒 GMC K Sierra - 4WD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - Allison 🢒 DTC P0218

Circuit Description

The flow of transmission fluid starts in the transmission pan. The transmission fluid is then drawn through the filter and the transmission case into the oil pump assembly. The oil pump pressurizes the fluid into main pressure, that is regulated at the main pressure regulator valve. From this point, fluid is directed to the torque converter clutch (TCC) solenoid and to the control main regulator valve and control main relief valve, into the control main filter assembly and on to all solenoids for use as control pressure. Hot fluid leaving the torque converter is routed through the converter flow valve, to cooler lines, and into the cooler assembly, located in the radiator. The vehicle may be equipped with an auxiliary oil cooler. The cooled fluid is returned to the transmission through the return cooler line and to the transmission lube circuit. The automatic transmission fluid temperature (TFT) sensor, which is part of the pressure switch manifold (PSM) assembly, is mounted to the valve body.

If the transmission control module (TCM) detects a high TFT for an extended period of time, then DTC P0218 sets.

DTC P0218 is a type C DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0218 Transmission Condition Overtemperature

Conditions for Running the DTC
    • DTCs P0711, P0712, P0713 are not active.
    •  The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts.
    • Engine speed is greater than 200 RPM for greater than 5 seconds.

Conditions for Setting the DTC

DTC P0218 sets when the TCM detects a transmission sump temperature greater than 126°C (252°F) for 10 seconds.

Action Taken When the DTC Sets
    • The TCM does not illuminate the malfunction indicator lamp (MIL).
    • The TCM freezes shift adapts from being updated.
    • The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
    • The TCM stores DTC P0218 in TCM history.
    • The TCM inhibits TCC engagement.

Conditions for Clearing the DTC
    • A scan tool can clear the code from the TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.
    • The TCM cancels the DTC default actions when the condition no longer exists and the DTC passes the test.

Diagnostic Aids
    • Verify the driving habits of the customer, such as trailer towing, etc.
    • The TFT should rise steadily during warm-up cycles, then stabilize.
    • DTC P0218 may set after DTC P0711 has set. Follow the diagnostic table for DTC P0711 before proceeding to the diagnostic for DTC P0218.
    • Repairing the condition that set DTC P0711 will likely eliminate DTC P0218.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step inspects for air restriction and loss of transmission fluid flow, causing an extremely high TFT.

Step

Action

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Install the scan tool.
  2. Turn ON the ignition, with the engine OFF.

    3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records. The Clear Info function will erase the data.

  3. Record the DTC Freeze Frame and Failure Records.
  4. Clear the DTC.
  5. Perform the Transmission Fluid Checking Procedure. Refer to Transmission Fluid Check .

Is the transmission fluid level correct?

Go to Step 3

Go to Transmission Fluid Check

3

  1. Inspect the engine cooling system for the following conditions:
    2. • Air flow restrictions
    • Air flow blockage
    • System fluid level and condition
    • Debris
  2. Inspect the transmission cooling system for the following conditions:
    3. • Air flow restrictions
    • Air flow blockage
    • System fluid level and conditions
    • Debris
    • Damaged cooler lines or hoses

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Perform the Line Pressure Check Procedure.

Refer to Line Pressure Check .

Is the line pressure correct?

Go to Step 6

Go to Step 5

5

Inspect the torque converter stator for damage.

Refer to Torque Converter Diagnosis .

Did you find and correct the condition?

Go to Step 6

Go to Symptoms - Automatic Transmission

6

Perform the following procedure in order to verify the repair:

  1. Clear the DTC.
  2. Using the scan tool, monitor the TFT.
  3. Start the engine.
  4. The TFT must be less than 122°C (252°F) for at least 10 seconds.
  5. Select Specific DTC.
  6. Enter DTC P0218.

Has the test run and passed?

Go to Step 7

Go to Step 2

7

With the scan tool, observe the stored information, capture info, and DTC Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK