Hummer H1 (2006+). Instruction - page 67
OBD-112
On-Board Diagnostics
_____________________________________________
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
• After starting a cold engine, the fuel temperature should be within a few degrees of the intake air temperature (IAT) sensor.
• Use the Temperature vs. Resistance table in order to test the fuel temperature sensor at various temperature levels in order to
evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns.
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
1.
Turn ON the ignition, with the engine OFF.
2.
Observe the fuel temperature sensor parameter with a scan
tool.
Is the fuel temperature sensor parameter more than the specified
value?
130°C
(266°F)
Go to Step 4
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.
Remove the air cleaner outlet duct from the air intake pipe.
2.
Disconnect the fuel temperature sensor.
3.
Turn ON the ignition, with the engine OFF.
4.
Observe the fuel temperature sensor parameter with a scan
tool.
Is the fuel temperature sensor parameter less than the specified
value?
-30°C (-
86°F)
Go to Step 6
Go to Step 5
5
1.
Turn OFF the ignition.
2.
Disconnect the engine control module (ECM).
3.
Test the signal circuit 324 (YL) of the fuel temperature sen-
sor for a short to ground or a short to any low reference cir-
cuit between C76 pin 27 and pin B of the fuel temp sensor.
Did you find and correct the condition?
Go to Step 8
Go to Step 7
6
Replace the faulty fuel temperature sensor.
Did you complete the replacement?
Go to Step 8
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On-Board Diagnostics OBD-113
5745804
7
Replace the faulty ECM.
Did you complete the replacement?
Go to Step 8
8
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 9
9
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-114
On-Board Diagnostics
_____________________________________________
DTC P0183 Fuel Temperature Sensor Circuit Low Voltage (Figure OBD-34)
Figure OBD-34: Fuel Temperature Sensor Circuit
Circuit Description
The fuel temperature sensor is a thermistor. The engine control module (ECM) supplies the fuel temperature sensor a reference
voltage of 5 volts on the signal circuit, and also provides a ground circuit to the sensor. When the fuel temperature sensor is cold,
the resistance is high. The fuel temperature sensor signal voltage remains near the supplied voltage cold, and decreases the signal
voltage as the sensor warms. The control module monitors the fuel temperature sensor signal circuit in order to calculate the tem-
perature of the fuel entering the engine. If the ECM detects an excessively high fuel temperature sensor voltage, a low temperature
indication, this DTC will set.
Conditions for Setting the DTC
• The fuel temperature sensor is less than -30°C (-22°F) for 2 seconds.
• DTC P0183 runs continuously within the above enabling conditions.
• 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.
_____________________________________________
On-Board Diagnostics OBD-115
5745804
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
• If a short to a separate 5-volt source occurs, this DTC may set. If this is the condition, a continuity test to all other ECM cir-
cuits will be necessary in order to diagnose the specific circuit.
• After starting a cold engine, the fuel temperature sensor should be within a few degrees of the intake air temperature (IAT)
reading.
• Use the Temperature vs. Resistance table to test the fuel temperature sensor at various temperature levels, and to evaluate
the possibility of a skewed sensor.
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
1.
Turn ON the ignition, with the engine OFF.
2.
Observe the Fuel Temperature Sensor parameter with a scan
tool.
Is the Fuel Temperature Sensor parameter less than the specified
value?
-30°C
(-22°F)
Go to Step 4
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 OFF the ignition.
2.
Disconnect the fuel temperature sensor.
3.
Turn ON the ignition, with the engine OFF.
4.
Measure the voltage from the signal circuit 324 (YL) of the
fuel temperature sensor to a good ground with a DVOM.
Is the voltage more than the specified value?
5.2 Volts
Go to Step 5
Go to Step 6
5
NOTE: If a short to battery voltage occurs, the fuel temperature
sensor may be damaged.
Test the fuel temperature sensor signal circuit for a short to volt-
age.
Did you find and correct the condition?
Go to Step 15
Go to Step 12
