Hummer H2. Manual — part 2471

4

3. Prevent one rear wheel from turning.

4. Rotate the other rear wheel by hand,

ensuring that the driveshaft is turning.

Does the voltage measure greater than the specified
value?

0.5 V

Go to Step 5

Go to Step 12

5

Measure the resistance from terminal C2-21 to
ground.
Does the resistance measure greater than the
specified value?

50 K

ohm

Go to Step 6

Go to Step 9

6

1. Reconnect the PCM connector C2.

2. Disconnect the engine wiring harness from

the VSS assembly.

3. Turn ON the ignition, with the engine OFF.

4. Test the high circuit of the VSS assembly for

a short to power.

Refer to Testing for a Short to Voltage and
extxref document="029_body-21"
filetype="sgml" extrefid="i162420">Wiring
Repairs in Wiring Systems.

Did you find and correct the condition?

-

Go to Step 15

Go to Step 14

7

1. Disconnect the engine wiring harness from

the VSS assembly.

2. Measure the resistance of the VSS assembly.

Does the resistance measure within the specified
range?

976-

2354

ohm

Go to Step 8

Go to Step 13

8

Was the resistance measured in Step 3 greater than
the specified value?

2354

ohm

Go to Step 10

Go to Step 11

9

Test the high circuit of the VSS assembly for a
short to ground.
Refer to Testing for Short to Ground and extxref
document="029_body-21" filetype="sgml"
extrefid="i162420">Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

-

Go to Step 15

-

1. Test the high circuit of the VSS assembly for

an open.

2. Test the low circuit of the VSS assembly for

an open.

2004 Hummer H2

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

10

Refer to Testing for Continuity and extxref
document="029_body-21" filetype="sgml"
extrefid="i162420">Wiring Repairs in
Wiring Systems.

Did you find and correct the condition?

-

Go to Step 15

-

11

Test the high circuit and the low circuit of the VSS
assembly for a short together.
Refer to Circuit Testing and extxref
document="029_body-21" filetype="sgml"
extrefid="i162420"> Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

-

Go to Step 15

-

12

1. Remove the VSS assembly.

2. Inspect the output shaft speed sensor rotor

for damage or misalignment.

3. Inspect the case extension bushing for wear.

Did you find and correct the condition?

-

Go to Step 15

Go to Step 13

13

Replace the VSS assembly.
Refer to Vehicle Speed Sensor (VSS)
Replacement .
Did you complete the replacement?

-

Go to Step 15

-

14

Replace the PCM.
Refer to Powertrain Control Module (PCM)
Replacement in Engine Controls - 6.0L (LQ4).
Did you complete the replacement?

-

Go to Step 15

-

15

Perform the following procedure in order to verify
the repair:

1. Select DTC.

2. Select Clear Info.

3. Operate the vehicle, so that the transmission

output speed is greater than 250 RPM for 2
seconds.

4. Select Specific DTC.

5. Enter DTC P0502.

Has the test run and passed?

-

Go to Step 16

Go to Step 2

16

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?

-

Go to Diagnostic

Trouble Code

(DTC) List in

Engine Controls -

2004 Hummer H2

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

DTC P0503

Fig. 3: Vehicle Speed Sensor (VSS) Assembly Diagram
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 an AC voltage as rotor teeth on
the output shaft of the transfer case pass through the sensor's magnetic field. The AC voltage level and the
number of pulses increase as the speed of the vehicle increases. The PCM converts the pulsing voltage to

6.0L (LQ4)

System OK

2004 Hummer H2

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and torque converter clutch
(TCC) scheduling.

When the PCM detects an unrealistically large drop in vehicle speed, then DTC P0503 sets. DTC P0503 is a
type B DTC.

Conditions for Running the DTC

z

No TFP manual valve position switch DTC P1810.

z

The engine speed is greater than 450 RPM.

z

The time since the last gear range change is greater than 6 seconds.

z

The time since the last AWD low state change is greater than 6 seconds.

z

The transmission output speed rise does not exceed 600 RPM within 2 seconds.

Conditions for Setting the DTC

The transmission output speed drop is greater than 1,300 RPM for 3 seconds when the transmission is not in
PARK or NEUTRAL.

Action Taken When the DTC Sets

z

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

z

The PCM commands a soft landing to second gear.

z

The PCM commands maximum line pressure.

z

The PCM inhibits TCC engagement.

z

The PCM inhibits fourth gear if the transmission is in hot mode.

z

The PCM freezes transmission adapt functions.

z

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.

z

The PCM stores DTC P0503 in PCM history during the second consecutive trip in which the Conditions
for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

z

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

z

A scan tool can clear the MIL/DTC.

z

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

z

The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is
OFF long enough in order to power down the PCM.

Diagnostic Aids

2004 Hummer H2

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2