DTC P0720. Chevrolet Joy 2008

For 1990-2009 cars

### Circuit Description

The vehicle speed sensor (VSS) provides vehicle speed information to the transmission control module (TCM). This signal is used to control torque converter lock-up and gear change control.

### DTC Descriptor

This diagnostic procedure supports the following DTC: DTC P0720 Vehicle Speed Sensor Circuit.

### Conditions for Running the DTC

• | Transmission in Drive range

• | Turbine speed is more than 1,000 RPM.

• | Vehicle speed is more than 40 km/h (25 mph).

• | The voltage of the transmission fluid temperature sensor is between 0.1 and 2.4 volts.

• | Throttle position is more than 13 percent.

### Conditions for Setting the DTC

Vehicle speed is less than 5 km/h (3 mph) for more than 2 seconds.

### Action Taken When the DTC Sets

• | The malfunction indicator lamp (MIL) will illuminate.

• | The TCM will record operating conditions on the first time when the TCM detects a failure.

### Conditions for Clearing the MIL/DTC

• | The MIL will turn OFF when the malfunction has not occurred after 3 consecutive driving cycles and the ECM turns off the MIL on the next driving cycle (MIL off at the 4th driving cycle).

• | A history DTC will clear after 40 consecutive warm-up cycles without a fault.

• | Clear the DTCs with a scan tool.

### Diagnostic Aids

When DTC P0720 sets, the possible cause of the fault could be:

• | Open or short circuit in the wiring harness and/or connector

• | Vehicle speed sensor malfunction

• | Vehicle speed sensor rotor

• | Faulty TCM

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Automatic Transmission? | -- | Go to Step 2 | Go to Diagnostic System Check - Automatic Transmission

2

1. Turn the ignition OFF.
2. Disconnect the VSS wiring connector.
3. Turn the ignition ON with the engine OFF
4. Measure the voltage between terminal 1 of the VSS connector and the terminal 2 (ground).

Is the voltage reading in the specified range?

12 V

Go to Step 3

Go to Step 5

3 | Inspect the VSS for damage. Is the VSS damaged? | -- | Go to Step 4 | Go to Step 5
4 | Replace the vehicle speed sensor. Is the action complete? | -- | System OK | --

5

1. Disconnect the vehicle speed sensor wiring connector and transmission control module (TCM) connector.
2. Check for continuity between the vehicle speed terminal 3 of the transmission wiring connector and terminal 32 of the TCM wiring connector.

Is there continuity?

Go to Step 7

Go to Step 6

6 | Repair the wiring harness as necessary. Refer to Wiring Repairs . Is the action complete? | -- | System OK | --
7 | Replace the TCM. Refer to Transmission Control Module Replacement . Is the action complete? | -- | Go to Step 8 | --

8

1. After the repair, use a scan tool clear info function and road test the vehicle.
2. Review the DTC info.
3. Observe the DTC Information with a scan tool.

Did the last test fail or is the current DTC displayed?

--

Go to Step 2

System OK