Hummer H1 (2002+). Manual - part 268
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PCM/Tech 1 Scan Tool 5
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05745159
PCM Programming (TDC Offset)
The PCM will automatically activate the TDC Offset program when the engine coolant is greater than 170°F (77°C). If the PCM is
not programmed with a TDC Offset, a P1214 will set. If the PCM and Fuel injection pump are replaced together, or the front cover
of the engine is replaced, the TDC offset will have to be “cleared” to allow the PCM to relearn the new value.
Table 3-1: Powertrain OBD System Check
Step
Action
Value(s)
Yes
No
1
1) Turn on the ignition leaving the engine OFF.
2) Observe the Malfunction Indicator Lamp (MIL).
Is the MIL on?
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Go to Step 2
Go to “No Mal-
function Indica-
tor Lamp”
2
1) Turn OFF the ignition.
2) Install the scan tool.
3) Turn ON the ignition.
Does the scan tool display PCM data
—
Go to Step 3
Go to “No Scan
Tool Data”
3
Using the scan tool to command the MIL to turn OFF.
Does the MIL turn OFF?
—
Go to Step 4
Go to DTC
P1641 MIL Con-
trol Circuit
4
Check for DTCs using the scan tool.
Were any current, history, or MIL request DTCs set?
—
Go to Step 5
Go to Step 6
5
Using the scan tool, store the Freeze Frame Data and the
Failure Records Data.
Is the action complete?
—
Go the Applica-
ble DTC Table
—
6
Does the engine start and continue to run?
—
Go to step 7
Go to “Engine
Cranks but Does
Not Run”
7
1) Turn ON the ignition leaving the engine OFF.
2) Check the ECT.
3) Start the engine.
4) Allow the engine temperature to reach the specified
value.
5) While the engine is reaching the operating temperature,
check the ECT.
6) Compare the scan tool values of the sensors with the typ-
ical values shown in the Scan Tool Values.
Are the displayed values normal or within typical ranges?
90°C-95°C
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8
Refer to indicated “Component(s) System” checks.
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