Hummer H1 (2006+). Manual - part 85

OBD-184

On-Board Diagnostics

_____________________________________________

DTC P0507 Idle Speed Too High

Circuit Description

The engine control module (ECM) adjusts the fuel delivery in order to control crankshaft speed at idle. If the ECM detects the en-
gine speed is incorrect for the amount of fuel that is delivered, DTC P0507 sets.

Conditions for Setting the DTC

The actual idle speed is more than 100 RPM over the target idle speed.

Action Taken When the DTC Sets

• The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diag-

nostic 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 consecu-
tive 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 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.

Diagnostic Aids

Inspect for one of the following:

• A crankcase overfill causing oil to be forced through the positive crankcase ventilation (PCV) system

• An aftermarket performance kit using an external fuel source

• An engine mechanical condition

Step

Action

Value(s)

Yes

NOTE: Before clearing DTC(s) use the scan tool “Capture info”
to record Freeze Frame and Failure Records for reference, as data
will be lost when “Clear Info” function is used

Was the “On-Board Diagnostic (OBD) System Check” per-
formed?

Go to step 2.

Go to OBD Sys-

tem Check.

Are any other DTCs set?

Go to the DTC

in order

Go to Step 3

Attempt to start the engine.

Does the engine crank?

Go to Step 4

Go to Engine

Will Not Crank

Does the engine start?

Go to Diagnos-

tic Aids

Go to Engine

Cranks but Does

Not Run

_____________________________________________

On-Board Diagnostics OBD-185

5745804

DTC P0522 Oil Pressure Circuit Low Voltage (Figure OBD-53)

Figure OBD-53: Oil Pressure Sensor Circuit

Circuit Description

The engine oil pressure (EOP) sensor changes resistance based on engine oil pressure. The Engine control module (ECM) monitors
the signal circuit of the EOP sensor. When the oil pressure is high, the sensor resistance is high, and the ECM senses a high signal
voltage. When the oil pressure is low, the sensor resistance is low, and the ECM senses a low signal voltage. The ECM sends the
engine oil pressure information to the instrument panel cluster (IPC) via the class 2 serial data circuit.

Conditions for Setting the DTC

• The ECM detects that the EOP sensor signal circuit is less than 0.4 volts.

• The above condition is present for greater than 9 seconds.

OBD-186

On-Board Diagnostics

_____________________________________________

Action Taken When the DTC Sets

• The ECM records the operating conditions at the time the diagnostic test fails. The ECM displays this information in the

Failure Records on the scan tool.

• The IPC illuminates the engine oil pressure indicator.

Conditions for Clearing the DTC

• The DTC becomes history when the conditions for setting the DTC are no longer present.

• The history DTC clears after 40 malfunction free warm-up cycles.

• The ECM receives a clear code command from the scan tool.

Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the
Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine
how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Step

Action

Value(s)

Yes

NOTE: Before clearing DTC(s) use the scan tool “Capture info”
to record Freeze Frame and Failure Records for reference, as data
will be lost when “Clear Info” function is used

Was the “On-Board Diagnostic (OBD) System Check” per-
formed?

Go to step 2.

Go to OBD Sys-

tem Check.

Install a scan tool.

Turn the ignition ON, with the engine OFF.

With the scan tool, observe one of the following engine oil
pressure parameters:

• Monitored Oil Pressure parameter in the IPC Data 1 data

list-6.6L diesel only.

• Engine Oil Pressure Sensor parameter in the ECM Engine

Data 2 data list.

Does the scan tool indicate that the Engine Oil Pressure parame-
ter is at or less than the specified value?

0 kPa (0

psi)

0.4 Volts

Go to Step 3

Go to Diagnos-

tic Aids

Is DTC P0641 current in the engine control module (ECM)?

Go to P0641

Go to Step 4

Turn the ignition OFF.

Disconnect the engine oil pressure (EOP) sensor.

Connect a 3-ampere fused jumper between the EOP sensor
signal circuit 619 (TN/WH) and the 5-volt reference circuit
617 (GY) of the EOP sensor.

With the scan tool, observe one of the following engine oil
pressure parameters:

• Monitored Oil Pressure parameter in the IPC Data 1 data

list-6.6L diesel only.

• Engine Oil Pressure Sensor parameter in the ECM Engine

Data 2 data list.

Does the scan tool indicate that the Engine Oil Pressure parame-
ter is at or greater than the specified value?

550 kPa

(80 psi)

4.6 Volts

Go to Step 8

Go to Step 5

_____________________________________________

On-Board Diagnostics OBD-187

5745804

Disconnect the fused jumper.

Measure the voltage between the 5-volt reference circuit 617
(GY) of the EOP sensor and the low reference circuit 618
(BK) of the EOP sensor.

Does the voltage measure greater than the specified value?

4.6 Volts

Go to Step 7

Go to Step 6

Test the 5 volt reference circuit 617 (GY) of the EOP sensor for
an open or for a high resistance between C75 pin 34 and pin B of
the EOP sensor.

Did you find and correct the condition?

Go to Step 12

Go to Step 9

Test the EOP sensor signal circuit 619 (TN/WH) for an open, for
a short to ground, or for a high resistance between C76 pin 25 and
pin C of the EOP sensor.

Did you find and correct the condition?

Go to Step 12

Go to Step 9

Inspect for poor connections at the harness connector of the EOP
sensor.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

Inspect for poor connections at the harness connector of the
ECM.

Did you find and correct the condition?

Go to Step 12

Go to Step 11

Replace the faulty engine oil pressure sensor.

Did you complete the replacement?

Go to Step 12

Replace the faulty ECM.

Did you complete the replacement?

Go to Step 12

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

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 13

Using the Scan Tool select “Capture Info,” Review Info.” Are
any DTC’s displayed that have not been diagnosed?

Go to the appli-

cable DTC

table.

System OK.

Step

Action

Value(s)

Yes

Content .. 83 84 85 86 ..