Hummer H2. Manual — part 1526

10: This step will determine if high resistance has caused this DTC to set.

12: A high resistance short from the signal circuit to the low reference circuit can cause this DTC to set.

DTC P0116

Step

Action

Values

Yes

No

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

1

Did you perform the Diagnostic System Check-
Engine Controls?

-

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

2

Inspect the cooling system coolant level.
Is the cooling system coolant low?

-

Go to Draining and

Filling Cooling

System in Engine

Cooling

Go to Step 3

3

Observe and record the ambient air temperature
of the vehicle environment using an accurate
thermometer.
Did you complete the action?

-

Go to Step 4

-

4

Has the engine been OFF for the specified
amount of time?

IMPORTANT:

The vehicle needs to have been OFF for at
least 10 hours for the ECT and the intake air
temperature (IAT) to be at ambient
temperature. The vehicle should not have
changed environments during this time.

10 hrs

Go to Step 7

Go to Step 5

5

1. Remove the mass air flow/intake air

temperature (MAF/IAT) sensor. Refer to
Mass Air Flow (MAF)/Intake Air
Temperature (IAT) Sensor
Replacement .

2. Remove the ECT sensor. Refer to Engine

Coolant Temperature (ECT) Sensor
Replacement .

3. Place the sensors on a work surface away

from any heat source.

4. Allow the sensors to reach the ambient air

temperature for 30-60 minutes.

Are the sensors at the ambient temperature?

-

Go to Step 6

-

1. Connect the MAF/IAT sensor to the

electrical connector, but DO NOT install it.

2004 Hummer H2

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

Hummer H2

6

2. Insulate the sensor from any engine heat

source.

3. Connect the ECT sensor to the electrical

connector, but DO NOT install it.

4. Insulate the sensor from any engine heat

source.

Are the sensors connected?

-

Go to Step 7

-

7

1. Turn ON the ignition.

2. Take a snapshot of the Engine Data List

with a scan tool.

3. Review the snapshot data that was taken

with the scan tool.

4. Observe the ECT Sensor parameter with a

scan tool.

5. Observe the IAT Sensor parameter with a

scan tool.

Is the difference between the ECT Sensor
parameter and the IAT Sensor parameter more
than the specified value?

IMPORTANT:

The IAT sensor will start to warm-up as soon
as the ignition is turned ON.

15°C

(27°F)

Go to Step 8

Go to

Intermittent

Conditions

8

Observe the recorded IAT Sensor parameter.
Is the difference between the IAT Sensor
parameter and the ambient air temperature less
than the specified value?

8°C

(14°F)

Go to Step 9

Go to Step 10

9

Observe the recorded ECT Sensor parameter.
Is the difference between the ECT Sensor
parameter and the ambient air temperature less
than the specified value?

8°C

(14°F) Go to Intermittent

Conditions

Go to Step 12

10

1. Disconnect the MAF/IAT sensor.

2. Test for an intermittent and for a poor

connection at the IAT 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 25

Go to Step 11

1. At the sensor, measure the resistance

between the IAT signal and the IAT low

2004 Hummer H2

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

Hummer H2

11

reference terminals with a DMM and
record the value. Refer to Circuit Testing
in Wiring Systems.

2. Observe the recorded ambient air

temperature.

3. Compare the resistance measurement of the

IAT sensor to the ambient air temperature
using the Temperature vs. Resistance table.
Refer to Temperature vs Resistance .

Is the resistance measurement of the IAT sensor
within the specified range?

-

Go to Step 14

Go to Step 22

12

1. Disconnect the ECT sensor.

2. Inspect for the following conditions:

z

An ECT sensor leaking engine
coolant internally through the sensor

z

Corrosion on the ECT sensor
terminals

z

Corrosion on the ECT harness
connector terminals

Did you find and correct the condition?

-

Go to Step 25

Go to Step 13

13

1. At the sensor, measure the resistance

between the ECT signal and the ECT low
reference terminals with a DMM and
record the value. Refer to Circuit Testing
in Wiring Systems.

2. Observe the recorded ambient air

temperature.

3. Compare the resistance measurement of the

ECT sensor to the ambient air temperature
using the Temperature vs. Resistance table.
Refer to Temperature vs Resistance .

Is the resistance measurement of the ECT sensor
within the specified range?

-

Go to Step 15

Go to Step 23

14

Measure the voltage from the IAT signal circuit
to a good ground with a DMM. Refer to Circuit
Testing in Wiring Systems.
Is the voltage within the specified range?

4.8-5.2

V

Go to Step 16

Go to Step 17

15

Measure the voltage from the ECT signal circuit
to a good ground with a DMM. Refer to Circuit
Testing in Wiring Systems.
Is the voltage within the specified range?

4.8-5.2

V

Go to Intermittent

Conditions

Go to Step 19

2004 Hummer H2

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

Hummer H2

16

1. Turn OFF the ignition for 90 seconds to

allow the control modules to power down.

2. Measure the resistance from the low

reference circuit of the IAT sensor to a
good ground with a DMM. Refer to
Circuit Testing in Wiring Systems.

Is the resistance less than the specified value?

IMPORTANT:

All electrical components and accessories
must be turned OFF. Performing this step will
disable the diagnostic for 10 hours.

5 ohm

Go to Intermittent

Conditions

Go to Step 18

17

Test the IAT signal circuit for a high resistance.
Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you find and correct the condition?

-

Go to Step 25

Go to Step 20

18

Test the IAT low reference circuit for a high
resistance. Refer to Circuit Testing and Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 25

Go to Step 20

19

Test the ECT signal circuit for a high resistance
short to ground. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 25

Go to Step 21

20

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 25

Go to Step 24

21

Test for shorted terminals and poor connections
at the PCM. Refer to Testing for Intermittent
Conditions and Poor Connections , Connector
Repairs in Wiring Systems, and Intermittent
Conditions .
Did you find and correct the condition?

-

Go to Step 25

Go to Step 24

22

Replace the MAF/IAT sensor. Refer to Mass Air
Flow (MAF)/Intake Air Temperature (IAT)
Sensor Replacement .
Did you complete the replacement?

-

Go to Step 25

-

23

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

-

Go to Step 25

-

2004 Hummer H2

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

Hummer H2