Circuit Description
The transmission control module (TCM) provides the engine control module (ECM) vehicle speed information through the high-speed communications on the controller area network (CAN). Vehicle speed is produced by the AC current generated through the transmission output shaft speed (OSS) sensor as the output shaft rotates. The ECM continuously monitors the vehicle speed signal supplied by the TCM. If the ECM does not receive vehicle speed data from the TCM, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0501 Vehicle Speed Sensor (VSS) Performance
Conditions for Running the DTC
| • | The engine is running. |
| • | The vehicle speed is 0 km/h (0 mph) for 25 seconds. |
| • | The engine speed is more than 2500 RPM. |
| • | The ignition 1 voltage is more than 10 volts. |
| • | The mass air flow (MAF) is more than 18 g/s. |
| • | DTC P0501 runs continuously when the above conditions are met. |
Conditions for Setting the DTC
The ECM detects that the vehicle speed is 0 km/h (0 mph) for more than 26 seconds.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | |
2 |
Important: Record all Failure Records before clearing the DTC. Using Clear Info erases the Failure Records from the engine control module (ECM) and transmission control module (TCM). Did you record any TCM Freeze Frame/Failure Records? | Go to Diagnostic Trouble Code (DTC) List/Type in Automatic Transmission - ZF 4HP 16 | Go to Step 3 |
3 | Did DTC P0501 fail this ignition? | Go to Step 4 | Go to Intermittent Conditions |
4 | Did any other transmission control module (TCM) DTCs set? | Go to Diagnostic Trouble Code (DTC) List/Type in Automatic Transmission - ZF 4HP 16 | Go to Step 5 |
5 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 6 | -- |
6 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 7 |
7 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK | |
