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 B DTC.
This diagnostic procedure supports the following DTC:
DTC P0727 Engine Speed No Signal
The engine is running.
The engine speed is invalid for 2.0 seconds.
• | The TCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | The TCM commands maximum line pressure. |
• | The TCM freezes transmission adaptive functions. |
• | At the time of the first failure, the TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record. |
• | At the time of the second failure, 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. |
• | The ECM turns OFF the MIL after the sixth 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 | Value(s) | Yes | No | ||||
---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||
2 |
Important:
Did you record any ECM Failure Records? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 | ||||
3 | Did you record a TCM Failure Record for DTC C0100? | -- | -- | 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 - 4.6L | ||||
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 - Vehicle in Vehicle DTC Information | Go to Step 8 | ||||
8 | Replace the TCM. Refer to Control Module References in Computer/Integrated Systems for replacement, set-up and programming. 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 - Vehicle in Vehicle DTC Information | System OK |