Hummer H2. Manual - part 1627

DTC P0117

Circuit Description

The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine
coolant. The powertrain control module (PCM) supplies 5 volts to the ECT signal circuit and a ground for the
ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the
sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT signal
circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM
detects an excessively low ECT signal voltage, which is a high temperature indication, DTC P0117 sets.

Conditions for Running the DTC

The engine run time is more than 10 seconds.

The engine run time is less than 10 seconds when the intake air temperature (IAT) is less than 50°C (122°
F).

Conditions for Setting the DTC

Replace the PCM. Refer to Powertrain Control
Module (PCM) Replacement .
Did you complete the replacement?

Go to Step 25

Reassemble the vehicle as necessary.
Did you complete the action?

Go to Step 26

1. Clear the DTCs with a scan tool.

2. Turn OFF the ignition for 10 hours.

3. Start the engine.

4. Operate the vehicle within the Conditions

for Running in 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?

IMPORTANT:

This DTC will not run without the ignition being
OFF for at least 10 hours.

Go to Step 2

Go to Step 27

Observe the Capture Info with a scan tool.
Are there any DTCs that have not been
diagnosed?

Go to Diagnostic

Trouble Code

(DTC) List

System OK

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0068 To DTC P0141/P0161) - 4.8L, 5.3L, and 6.0L -

Hummer H2

The PCM detects that the ECT sensor parameter is more than 138°C (280°F) for more than 20 seconds.

Action Taken When the DTC Sets

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

An overheating condition may cause this DTC to set.

After starting the engine, the ECT should rise steadily to about 90°C (194°F) then stabilize when the
thermostat opens.

Use the Temperature vs. Resistance table to test the ECT sensor at various temperature levels to evaluate
the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns. Refer to
Temperature vs Resistance .

If the condition is suspected of being an intermittent, refer to Intermittent Conditions .

DTC P0117 - ECT Sensor Circuit Low Voltage

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or
Engine Controls Connector End Views

Did you perform the Diagnostic System Check-
Engine Controls?

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

Observe the engine coolant temperature (ECT)
sensor parameter with a scan tool.
Is the ECT sensor parameter more than the specified
value?

138°C

(280°F)

Go to Step 4

Go to Step 3

1. Observe the Freeze Frame/Failure Records for

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0068 To DTC P0141/P0161) - 4.8L, 5.3L, and 6.0L -

Hummer H2

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

Go to Diagnostic

Aids

1. Disconnect the ECT sensor.

2. Observe the ECT sensor parameter with a scan

tool.

Is the ECT sensor parameter less than the specified
value?

-38°C (-

36°F)

Go to Step 6

Go to Step 5

Test the signal circuit of the ECT sensor for a short
to ground or a short to the ECT low reference circuit.
Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you find and correct the condition?

Go to Step 10

Go to Step 8

Test for an intermittent and for a poor connection at
the ECT sensor. Refer to Testing for Intermittent
Conditions and Poor Connections and Connector
Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 10

Go to Step 7

Replace the ECT sensor. Refer to Engine Coolant
Temperature (ECT) Sensor Replacement .
Did you complete the replacement?

Go to Step 10

Test for an intermittent and for a poor connection at
the powertrain control module (PCM). Refer to
Testing for Intermittent Conditions and Poor
Connections and Connector Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 10

Go to Step 9

Replace the PCM. Refer to Powertrain Control
Module (PCM) Replacement .
Did you complete the replacement?

Go to Step 10

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

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0068 To DTC P0141/P0161) - 4.8L, 5.3L, and 6.0L -

Hummer H2

DTC P0118

Circuit Description

The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine
coolant. The ECT sensor has a signal circuit and a low reference circuit. The powertrain control module (PCM)
supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold,
the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor
resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM
detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively high ECT signal voltage,
which is a low temperature indication, DTC P0118 sets.

Conditions for Running the DTC

The engine has been running for more than 60 seconds.

The engine run time is less than 60 seconds when the intake air temperature (IAT) is more than 0°C (32°F)

Conditions for Setting the DTC

The PCM detects that the ECT sensor parameter is less than -38°C (-36°F) for 20 seconds.

Action Taken When the DTC Sets

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition
cycle that the diagnostic runs and fails.

Conditions for Clearing the MIL/DTC

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles

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 11

Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?

Go to

Diagnostic

Trouble Code

(DTC) List

System OK

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0068 To DTC P0141/P0161) - 4.8L, 5.3L, and 6.0L -

Hummer H2

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