Hummer H2. Manual - part 1669

1. Observe the Freeze Frame/Failure Records for

this DTC.

2. Turn OFF the ignition for 30 seconds.

3. Start the engine.

4. Operate the vehicle within the Conditions for

Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/Failure
Records.

Does the DTC fail this ignition?

Go to Step 4

Go to Intermittent

Conditions

Inspect the fuse that supplies voltage to the MIL.
Is the fuse open?

Go to Step 12

Go to Step 5

1. Turn OFF the ignition.

2. Disconnect the powertrain control module

(PCM).

3. Turn ON the ignition.

Is the MIL OFF?

Go to Step 6

Go to Step 13

1. Turn OFF the ignition.

2. Remove the fuse that supplies voltage to the

MIL.

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

4. Measure the voltage from the MIL control

circuit in the PCM to a good ground.

Is the voltage less than the specified value?

0.3 V

Go to Step 7

Go to Step 14

1. Turn OFF the ignition.

2. Install the fuse that supplies voltage to the

MIL.

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

4. Connect a 3-amp fused jumper wire between

the MIL control circuit of the PCM and a good
ground.

Is the MIL illuminated?

Go to Step 11

Go to Step 8

1. Turn OFF the ignition.

2. Remove the instrument panel cluster (IPC).

Refer to Instrument Panel Cluster (IPC)
Replacement in Instrument Panel, Gauges,
and Console.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0507 (TAC) To DTC U0107) - 4.8L, 5.3L, and 6.0L -

Hummer H2

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

4. Probe the MIL voltage supply circuit of the

IPC harness connector with a test lamp that is
connected to a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 15

Test the MIL control circuit for an open or high
resistance. Refer to Circuit Testing and Wiring
Repairs in Wiring Systems.
Did you find and correct a condition?

Go to Step 18

Go to Step 10

Test for an intermittent and for a poor connection at
the IPC. Refer to Testing for Intermittent
Conditions and Poor Connections and Connector
Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 18

Go to Step 16

Test for an intermittent and for a poor connection at
the PCM. Refer to Testing for Intermittent
Conditions and Poor Connections and Connector
Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 18

Go to Step 17

Repair the short to ground in the voltage supply
circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to Step 18

Repair the short to ground in the MIL control circuit.
Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to Step 18

Repair the short to voltage in the MIL control circuit.
Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to Step 18

Repair the open in the MIL voltage supply circuit.
Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?

Go to Step 18

Replace the IPC. Refer to Instrument Panel
Cluster (IPC) Replacement in Instrument Panel,
Gauges, and Console.
Did you complete the replacement?

Go to Step 18

Replace the PCM. Refer to Powertrain Control
Module (PCM) Replacement .
Did you complete the replacement?

Go to Step 18

1. Clear the DTCs with a scan tool.

2. Turn OFF the ignition for 30 seconds.

3. Start the engine.

4. Operate the vehicle within the Conditions for

Running the DTC. You may also operate the

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0507 (TAC) To DTC U0107) - 4.8L, 5.3L, and 6.0L -

Hummer H2

DTC P0651

Circuit Description

The powertrain control module (PCM) provides 5 volts to the following sensors:

The air conditioning (A/C) pressure sensor.

The fuel tank pressure (FTP) sensor

These 5-volt reference circuits are independent of each other outside the PCM, but are bussed together inside
the PCM. Therefore a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt
reference circuits. The PCM monitors the voltage on the 5-volt reference circuit. If the PCM detects that the
voltage is out of tolerance, DTC P0651 sets.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The PCM detects a voltage out of tolerance condition on the 5-volt reference circuit.

The above condition is present for longer than 10 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

vehicle within the conditions that you
observed from the Freeze Frame/Failure
Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 19

Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?

Go to

Diagnostic

Trouble Code

(DTC) List

System OK

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0507 (TAC) To DTC U0107) - 4.8L, 5.3L, and 6.0L -

Hummer H2

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.

Test Description

The number below refers to the step number on the diagnostic table.

9: A short to voltage on the signal circuit of the fuel tank pressure (FTP) sensor will backfeed through the
sensor into the 5-volt reference circuit and set this DTC.

DTC P0651

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Component Views or Powertrain Control
Module (PCM) Connector End Views

Did you perform the Diagnostic System Check -
Engine Controls?

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

1. Observe the Freeze Frame/Failure Records

for this DTC.

2. Turn OFF the ignition for 30 seconds.

3. Start the engine.

4. Operate the vehicle within the Conditions

for Running the DTC. You may also
operate the vehicle within the conditions
that you observed from the Freeze
Frame/Failure Records.

Does the DTC fail this ignition?

Go to Step 3

Go to Intermittent

Conditions

1. Turn OFF the ignition.

2. Disconnect the air conditioning (A/C)

pressure sensor.

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

4. Measure the voltage from the 5-volt

reference circuit of the A/C pressure sensor
to a good ground with a DMM. Refer to
Circuit Testing in Wiring Systems.

Is the voltage within the specified range?

4.8-5.2

Go to Step 4

Go to Step 5

1. Connect the A/C pressure sensor.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0507 (TAC) To DTC U0107) - 4.8L, 5.3L, and 6.0L -

Hummer H2

Content .. 1667 1668 1669 1670 ..