Hummer H2. Manual — part 1668

Action Taken When the DTC Sets

z

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition
cycle that the diagnostic runs and fails.

z

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

z

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles
that the diagnostic runs and does not fail.

z

A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

z

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other
emission related diagnostic.

z

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 manifold absolute pressure (MAP) sensor will backfeed
through the sensor into the 5-volt reference circuit and set this DTC.

DTC P0641

Step

Action

Values

Yes

No

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

1

Did you perform the Diagnostic System Check -
Engine Controls?

-

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

2

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.

-

Go to Intermittent

2004 Hummer H2

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

Hummer H2

Does the DTC fail this ignition?

Go to Step 3

Conditions

3

1. Turn OFF the ignition.

2. Disconnect the engine oil pressure (EOP)

sensor.

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

4. Measure the voltage from the 5-volt

reference circuit of the EOP 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

V

Go to Step 4

Go to Step 5

4

1. Connect the EOP sensor.

2. Disconnect the manifold absolute pressure

(MAP) sensor.

3. Measure the voltage from the 5-volt

reference circuit of the MAP 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

V

Go to

Intermittent

Conditions

Go to Step 11

5

Is the voltage measured in step 3 more than the
specified value?

5.2 V

Go to Step 8

Go to Step 6

6

Monitor the DMM while disconnecting the MAP
sensor.
Does the voltage return to within the specified
range when the MAP sensor is disconnected?

4.8-5.2

V

Go to Step 10

Go to Step 7

7

1. Turn OFF the ignition.

2. Disconnect the powertrain control module

(PCM).

3. Test the 5-volt reference circuit for a short

to ground or any sensor low reference
circuit. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

-

Go to Step 13

Go to Step 12

8

Test all 5-volt reference circuits for a short to
voltage. Refer to Circuit Testing and Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 13

Go to Step 9

9

Test the MAP sensor signal circuit for a short to
voltage. Refer to Circuit Testing and Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 13

Go to Step 12

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 P0650

Circuit Description

The malfunction indicator lamp (MIL) is located on the instrument panel cluster (IPC). The MIL informs the
driver that an emission system fault has occurred and that the engine control system requires service. The
control module monitors the MIL control circuit for conditions that are incorrect for the commanded state of the
MIL. For example, a failure condition exists if the control module detects low voltage when the MIL is
commanded OFF, or high voltage when the MIL is commanded ON. If the control module detects an improper
voltage on the MIL control circuit, DTC P0650 will set.

Conditions for Running the DTC

z

The engine speed is more than 400 RPM.

z

The ignition voltage is between 6-18 volts.

Conditions for Setting the DTC

z

The control module detects that the commanded state of the MIL driver and the actual state of the control
circuit do not match.

10

Replace the MAP sensor. Refer to Manifold
Absolute Pressure (MAP) Sensor
Replacement .
Did you complete the replacement?

-

Go to Step 13

-

11

Replace the EOP sensor. Refer to Engine Oil
Pressure Sensor and/or Switch Replacement in
Engine Mechanical.
Did you complete the replacement?

-

Go to Step 13

-

12

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

-

Go to Step 13

-

13

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 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 14

14

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

z

The conditions are present for a minimum of 5 seconds.

Action Taken When the DTC Sets

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

z

A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

z

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other
emission related diagnostic.

z

Clear the MIL and the DTC with a scan tool.

Test Description

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

5: This step tests for a short to ground in the MIL control circuit. With the powertrain control module
(PCM) disconnected and the ignition ON, the MIL should be OFF.

6: This step tests for a short to voltage on the MIL control circuit. With the fuse removed, there should be
no voltage on the MIL control circuit.

DTC P0650

Step

Action

Values

Yes

No

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

1

Did you perform the Diagnostic System Check -
Engine Controls?

-

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

2

1. Verify whether the instrument cluster is

operational. If the instrument panel (I/P) is
completely inoperative, refer to Diagnostic
System Check - Instrument Cluster in
Instrument Panel, Gauges and Console.

2. Command the MIL ON and OFF with a scan

tool.

Does the MIL turn ON and OFF when commanded
with a scan tool?

-

Go to Step 3

Go to Step 4

2004 Hummer H2

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

Hummer H2