Hummer H3. Manual — part 1457

Diagnostic Trouble Code (DTC) List/Type

DTC P0502

Fig. 8: Vehicle Speed Sensor (VSS) Circuit Schematic
Courtesy of GENERAL MOTORS CORP.

Circuit Description

The vehicle speed sensor (VSS) assembly provides vehicle speed information to the powertrain
control module (PCM). The VSS assembly is a permanent magnet generator. The VSS produces
alternating current (AC) as the rotor teeth on the output shaft of the transmission, 2WD or transfer
case, 4WD, pass through the magnetic field of the sensor. The frequency and amplitude of the AC
waveform increase as vehicle speed increases.

If the PCM detects no vehicle speed for a specified length of time, while other sensors indicate
that the vehicle is moving, DTC P0502 sets. DTC P0502 is a type B DTC.

Description

Federal and

California Emissions

Unleaded Fuel

Export

DTC P0502

B

B

DTC P0503

B

B

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0502 Vehicle Speed Sensor (VSS) Circuit Low Voltage

Conditions for Running the DTC

No VSS DTC P0503.

No TP sensor DTCs P0120 or P0121.

The TP sensor angle is 12 percent or more.

The engine speed is 1,000-6,800 RPM for 8 seconds.

The system voltage is 10-18 V.

Engine torque is 40-300 N.m (30-221 lb ft).

Conditions for Setting the DTC

The transmission output speed is 100 RPM or less for 3 seconds.

Action Taken When the DTC Sets

The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive
trip in which the Conditions for Setting the DTC are met.

The PCM disables Cruise Control.

The PCM records the operating conditions when the Conditions for Setting the DTC are
met. The PCM stores this information as Freeze Frame and Failure Records.

The PCM stores DTC P0502 in PCM history during the second consecutive trip in which
the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

The PCM turns OFF the MIL during the third consecutive ignition cycles in which the
diagnostic test runs and passes.

A scan tool can clear the MIL/DTC.

The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles
without an emission-related diagnostic fault occurring.

The PCM cancels the DTC default actions when the fault no longer exists and the DTC
passes.

Diagnostic Aids

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

Ensure the VSS is correctly torqued to the transmission housing.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

3: This step tests the ability of the VSS to produce an AC voltage. This step also verifies the
integrity of the wiring to the PCM.

4: This step tests the VSS circuit for correct resistance.

DTC P0502

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

2

1. Install a scan tool.

2. Turn ON the ignition, with

the engine OFF.

3. Record the DTC Freeze

Frame and Failure Records.

4. Clear the DTC.

5. Raise and support the drive

wheels.

6. Start and idle the engine.

7. Engage the transmission in

2nd gear.

8. Select Vehicle Speed

IMPORTANT:

Before clearing the DTC, use
the scan tool in order to
record the Freeze Frame and
Failure Records. Using the
Clear Info function erases the
Freeze Frame and Failure
Records from the PCM.

-

Go to Testing
for

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3

Sensor on the scan tool.

With the drive wheels rotating,
does the VSS increase when the
wheel speed increases?

Intermittent
Conditions
and Poor
Connections

Go to Step 3

3

1. Turn OFF the ignition.

2. Disconnect the PCM

connector C3.

3. Using the J 35616 GM

terminal test kit, connect the
DMM between the VSS
high signal circuit and the
VSS low signal circuit at
the PCM connector.

4. Select AC volts on the

DMM.

5. Turn ON the ignition, with

the engine OFF.

6. Rotate the right front drive

wheel by hand.

7. Observe the DMM display.

Can a voltage greater than the
specified value be obtained?

0.5 V AC

Go to Step 14 Go to Step 4

4

1. Leave the DMM test leads

connected.

2. Measure circuit resistance.

Is the circuit resistance within the
specified range?

1,300-3,160

ohms

Go to Step 8 Go to Step 5

5

Is the circuit resistance greater
than the specified value?

3,160 ohms

Go to Step 11 Go to Step 6

6

1. Leave the DMM test leads

connected.

2. Disconnect the VSS

connector at the
transmission.

1,300 ohms

2007 Hummer H3

2007 TRANSMISSION Manual Transmission - Aisin AR5 - H3