GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Spark 🢒 DTC 🢒 DTC P0720

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

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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