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