Circuit Description
Engine speed information is sent to the transmission control module (TCM) by the engine control module (ECM) through a communication network called the controller area network (CAN). Two circuits are used to communicate CAN data between the ECM and TCM. A fault in the CAN will not cause DTC P0727 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P0727.
When the ECM sends the TCM an invalid engine speed, then DTC P0727 will set. DTC P0727 is a type A DTC.
Conditions for Running the DTC
| • | No CAN DTC U2105. |
| • | The system voltage is 8-18 volts. |
| • | Trans. Protection Mode is OFF. |
| • | The ignition has been ON for at least 3.0 seconds. |
Conditions for Setting the DTC
The engine speed is invalid for 4.0 seconds.
Action Taken When the DTC Sets
| • | The TCM illuminates the malfunction indicator lamp (MIL). |
| • | The TCM turns Trans. Protection Mode ON. When Trans. Protection Mode is ON, the line pressure is at maximum, and updates to the transmission adaptive pressure (TAP) memory cells are discontinued. The transmission will operate in 5th gear. |
| • | Limit engine torque to 270 N·m (200 lb ft). |
| • | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record. |
| • | The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame. |
| • | The TCM stores DTC P0727 in TCM history. |
Conditions for Clearing the MIL/DTC
| • | The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request. |
| • | A scan tool can clear the MIL/DTC. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
| • | The TCM cancels the default actions when the ignition is OFF long enough in order to power down the TCM. |
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.2L (L61) | ||||
2 |
Important:
Did you record any ECM Failure Records? | -- | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 2.2L (L61) | Go to Step 3 | ||||
3 | Did you record a TCM Failure Record for DTC U2105? | -- | Go to DTC U2105 in Data Link Communications | Go to Step 4 | ||||
4 |
Is the Engine Speed within the specified range? | 500-1,000 RPM | Go to Step 5 | Go to Step 6 | ||||
5 | Road test the vehicle using various engine speeds. Did DTC P0727 reset? | -- | Go to Step 7 | Go to Intermittent Conditions in Engine Controls - 2.2L (L61) | ||||
6 |
Is the Engine Speed value within the specified range? | 500-1,000 RPM | Go to Step 7 | Go to Step 8 | ||||
7 | Did any other DTCs set? | -- | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 2.2L (L61) | Go to Step 8 | ||||
8 | Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 2.2L (L61). Is the action complete? | -- | Go to Step 9 | -- | ||||
9 | Perform the following procedure to verify the repair:
Has the test run and passed? | -- | Go to Step 10 | Go to Step 2 | ||||
10 | 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 in Engine Controls - 2.2L (L61) | System OK |
