Hummer H1 (2006+). Manual — part 94

OBD-220

On-Board Diagnostics

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Circuit Description

The glow plug controller has the ability to perform internal checks, an open or a short to ground on each of the glow plug circuits.
If the glow plug controller senses a problem in a glow plug circuit, the glow plug on the affected cylinder will be disabled and the
glow plug controller will send an error message to the engine control module (ECM). If this condition exists, the DTC will set.

Conditions for Setting the DTC

The glow plug controller detects an open or a short to ground in the glow plug circuit for less than 1 second.

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.

Step

Action

Value(s)

Yes

No

1

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.

2

Is DTC P0670 set?

Go to DTC

P0670

Go to Step 3

3

1.

Observe the Freeze Frame/Failure Records for this DTC.

2.

Turn OFF the ignition.

3.

Turn ON the ignition, with the engine OFF.

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 4

Go to Intermit-

tent Conditions

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On-Board Diagnostics OBD-221

5745804

4

1.

Turn ON the ignition, with the engine OFF.

2.

Probe the terminal on the affected glow plug, with an unpow-
ered test lamp connected to the ground.

NOTE: The glow plugs can only be commanded ON once per ig-
nition cycle. Turn the ignition OFF and ON to command the glow
plugs ON each time with a scan tool.

3.

Command the glow plugs ON, with a scan tool.

Does the test lamp illuminate with the glow plugs commanded
ON?

Go to Step 5

Go to Step 6

5

1.

Turn OFF the ignition.

2.

Disconnect the glow plug connector at the affected glow
plugs.

3.

Probe the terminal on the glow plug with an unpowered test
lamp connected to battery voltage.

Does the test lamp illuminate?

Go to Step 8

Go to Step 11

6

Test the affected glow plug harness between the glow plug con-
troller and the glow plug for the following conditions:

• An open

• A short to ground

• A short to voltage Refer to Circuit Testing and Wiring Re-

pairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 7

7

Test for an intermittent and for a poor connection at the harness
connector of the glow plug controller.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

8

NOTE: The DVOM and test leads must be calibrated to 0 ohms
in order to prevent misdiagnosis. Use the DVOM to perform this
test. Refer to the DVOM User Manual for calibration procedure.

Measure the resistance between the affected glow plug terminal
of the glow plug and a good ground on the engine with a DVOM.

Does the DVOM display a resistance below the specified value?

1 ohm

Go to Step 9

Go to Step 11

9

NOTE: The DVOM and test leads must be calibrated to 0 ohms
in order to prevent misdiagnosis. Use the DVOM to perform this
test. Refer to the DVOM User Manual for calibration procedure.

1.

Disconnect the glow plug controller harness connector.

2.

Measure the resistance from the affected glow plug supply
voltage circuit between the glow plug harness connector and
the glow plug controller harness connector with a DVOM.

Does the DVOM display a resistance below the specified value?

1 ohm

Go to Step 12

Go to Step 10

10

Repair or replace the glow plug harness.

Is the action complete?

Go to Step 13

11

Replace the faulty glow plug.

Did you complete the replacement?

Go to Step 13

Step

Action

Value(s)

Yes

No

OBD-222

On-Board Diagnostics

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12

Replace the faulty glow plug controller.

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 1

Go to Step 14

14

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

No

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On-Board Diagnostics OBD-223

5745804

DTC P0698 5 Volt Reference 3 Circuit Low Voltage (Figure OBD-63)

Figure OBD-63: 5 Volt Reference 3 Circuit

Circuit Description

The engine control module (ECM) provides 5 volts to the following sensors:

• The accelerator pedal position (APP) sensor 3

• The camshaft position (CMP) sensor

These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together inside the ECM. Therefore,
a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The ECM monitors
the voltage on the 5-volt reference circuit. If the ECM detects a low voltage condition, DTC P0698 sets.

Conditions for Setting the DTC

• The ECM detects the 5-volt reference 3 circuit voltage is less than 4.7 volts.

• The above condition is present for 2 seconds.

Action Taken When the DTC Sets

• The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

• The control module records the operating conditions at the time the diagnostic fails. The control module stores this informa-

tion in the Freeze Frame/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.