The engine control module (ECM) sends accelerator pedal position data to the transmission control module (TCM). The TCM uses this data to modify shift speeds. The data is sent to the TCM 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 P0120 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P0120.
When the TCM receives invalid accelerator pedal data from the ECM, DTC P0120 sets. DTC P0120 is a type A DTC.
This diagnostic procedure supports the following DTC:
DTC P0120 Throttle Position (TP) Sensor Circuit
No other CAN errors are present.
The TCM receives no valid throttle position data from the ECM for 1 second.
• | The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL). |
• | The TCM commands maximum line pressure. |
• | The TCM freezes transmission adaptive functions. |
• | The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records. |
• | 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 P0120 in TCM history. |
• | 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 DTC default actions when the ignition is OFF long enough in order to power down the TCM. |
Step | Action | Yes | No | ||||
---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||
2 |
Important:
Did you record any ECM Failure Records? | Go to Step 3 | |||||
3 |
Did DTC P0120 set again? | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections | ||||
4 | Did any other DTCs set? | Go to Step 5 | |||||
5 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Is the action complete? | Go to Step 6 | -- | ||||
6 | Perform the following operation to verify the repair:
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? | System OK |