Hummer H1 (2006+). Manual — part 69

OBD-120

On-Board Diagnostics

_____________________________________________

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

If any of the following DTCs are set, go to that DTC first.

P0642

P0643

Are any of these DTCs set?

Go to the Diag-

nostic for each

Trouble Code

in numerical

order

Go to Step 3

3

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.

Did the DTC fail this ignition?

Go to Step 4

Intermittent Go

To Diagnostic

Aids

4

1.

Turn ON the ignition, with the engine OFF.

2.

Observe the Actual Fuel Rail Pressure parameter with a scan
tool.

Is the Actual Fuel Rail Pressure within the specified range?

1-1.8 MPa

Go to Step 6

Go to Step 5

5

1.

Disconnect the fuel rail pressure (FRP) sensor connector.

2.

Probe the FRP 5-volt reference circuit 508 (TN) with a
DVOM connected to a good ground.

Does the voltage measure near the specified value?

5 Volts

Go to Step 7

Go to Step 6

6

1.

Test the 5-volt reference circuit 508 (TN) of the FRP sensor
for high resistance or an open between C75 pin 23 and pin C
of the FRP sensor connector.

2.

Repair as necessary.

Did you find and correct the condition?

Go to Step 17

Go to Step 14

7

1.

Verify that the ignition is ON, with the engine OFF.

2.

Verify the FRP sensor harness connector is still discon-
nected.

3.

Measure the voltage between the FRP sensor signal circuit
509 (YL) and a the low reference circuit 507 (OR/BK) PIN B
at the FRP harness connector.

Is the current more than the specified value?

5 Volts

Go to Step 10

Go to Step 8

8

1.

Turn OFF the ignition.

2.

Disconnect the negative battery cables.

3.

Measure the resistance from the low reference circuit 507
(OR/BK) of the FRP sensor to a good ground.

Is the resistance less than the specified value?

5 ohms

Go to Step 9

Go to Step 12

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On-Board Diagnostics OBD-121

5745804

9

1.

Turn OFF the ignition.

2.

Connect a 3-amp fused jumper wire between the signal cir-
cuit 509 (YL) of the FRP sensor and the low reference circuit
507 (OR/BK) of the FRP sensor.

3.

Turn ON the ignition, with the engine OFF.

4.

Observe the Actual FRP parameter with a scan tool.

Is the Actual FRP parameter at the specified value?

0 MPa

Go to Step 13

Go to Step 11

10

Test for a short to voltage in the FRP sensor signal circuit 509
(YL).

Did you find and correct the condition?

Go to Step 17

Go to Step 16

11

Test the signal circuit 509 (YL) of the FRP sensor for a high re-
sistance or an open between C76 pin 42 and pin A of the FRP
sensor connector.

Did you Find and correct the condition?

Go to Step 17

Go to Step 14

12

1.

Disconnect the engine control module (ECM).

2.

Test the low reference circuit 507 (OR/BK) of the FRP sen-
sor for a high resistance or an open between C75 pin 2 and
pin B of the FRP sensor connector.

Did you find and correct the condition?

Go to Step 17

Go to Step 14

13

Test for an intermittent and for a poor connection at the FRP sen-
sor.

Did you find and correct the condition?

Go to Step 17

Go to Step 15

14

Test for an intermittent and for a poor connection at the ECM.

Did you find and correct the condition?

Go to Step 17

Go to Step 16

15

Replace the faulty FRP sensor.

Did you complete the replacement?

Go to Step 17

16

Replace the faulty engine control module (ECM).

Did you complete the replacement?

Go to Step 17

17

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 18

18

1.

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

OBD-122

On-Board Diagnostics

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DTC P0201-P0208 Injector Control Circuit (Figure OBD-37)

Figure OBD-37: Injector Control Circuit

Circuit Description

The fuel injection control module (FICM) supplies high voltage to each fuel injector on the injector supply voltage circuits. The
FICM enables each fuel injector by grounding the command circuit between the FICM and the fuel injector. The FICM monitors
the status of the injector supply voltage circuits and the fuel injector command circuits. When a fuel injector circuit condition is de-
tected by the FICM, all of the fuel injectors on the affected injector supply voltage circuit will be disabled. If a circuit condition is
detected on a fuel injector circuit for cylinders 1, 4, 6, or 7, DTCs P0201, P0204, P0206, P0207 will set, along with DTC P2146. If
a circuit condition is detected on a fuel injector circuit for cylinders 2, 3, 5, or 8, DTCs P0202, P0203, P0205, P0208 will set, along
with DTC P2149.

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On-Board Diagnostics OBD-123

5745804

Conditions for Setting the DTC

• The FICM detects an incorrect current on a fuel injector circuit.

• The condition exists for less than 1 second.

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.

• The control module disables the set of fuel injectors that have a concern.

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

Observe the DTC information with a scan tool.

Are any of DTCs P0201, P0204, P0206, P0207, P0202, P0203,
P0205, or P0208 set?

Go to Step 4

Go to Step 3

3

1.

Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.

2.

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 4

Intermittent Go

To Diagnostic

Aids

4

Is DTC P2146 also set?

Go to Step 13

Go to Step 5