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Home >> Chevy Truck >> 2006 >> Uplander FWD V6-3.9L VIN 1 >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0116

P0116



DTC P0116

DTC DESCRIPTORS

DTC P0116
Engine Coolant Temperature (ECT) Sensor Performance

DTC P0128
Engine Coolant Temperature (ECT) Below Thermostat Regulations Temperature

DIAGNOSTIC FAULT INFORMATION




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

TYPICAL SCAN TOOL DATA

ECT Sensor Temperature:






CIRCUIT/SYSTEM DESCRIPTION

P0116
The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The control module supplies 5 volts to the signal circuit and a ground for the ECT low reference circuit. When the engine coolant temperature is low, the sensor resistance is high. When the engine coolant temperature is high, the sensor resistance is low. The control module uses this High Side Coolant Rationality test to determine if the ECT input is skewed high. The internal clock of the control module will record the amount of time the ignition is OFF. At restart the control module will compare the temperature difference between the ECT and the intake air temperature (IAT). Before failing this test, the control module will perform a calculation to determine the presence of an engine block heater. If the control module detects that the temperature difference between the ECT and the IAT is not within the calibrated range after the ignition OFF time, DTC P0116 sets.

P0128
An ECT sensor monitors the temperature of the coolant. This input is used by the control module for engine control and as an enabling criteria for some diagnostics. The air flow coming into the engine is accumulated and used to determine if the vehicle has been driven within the conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach the regulating temperature of the thermostat, the diagnostics that use ECT as enabling criteria may not run when expected. If the control module detects the calibrated amount of air flow and engine run time have been met, and the ECT has not met the minimum thermostat regulating temperature, DTC P0128 sets.

CONDITIONS FOR RUNNING THE DTC

P0116
- DTCs P0112, P0113, P0117, P0118, P0601, P0602, P0603, P0604, P0606, P0607, P062F, P2610 are not set.
- The ignition is ON.
- The IAT parameter is more than 15°C (59°F).
- The Fuel Level Sensor parameter is more than 10 percent.
- The vehicle has a minimum ignition OFF time of 8 hours.
- This diagnostic runs once per ignition cycle when the above conditions are met.

P0128
- DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118 are not present.
- The startup ECT is less than 75°C (167°F).
- The IAT parameter is more than -7°C (+19°F).
- The engine run time is between 30-1,800 seconds.
- The vehicle is driven more than 0.8 kilometer (0.5 mile) at more than 8 km/h (5 mph).
- This diagnostic runs once per ignition cycle when the above conditions are met.

CONDITIONS FOR SETTING THE DTC

P0116
- The control module detects a temperature difference between the ECT sensor and the intake air temperature (IAT) sensor of more than 100°C (180°F) at start up. OR
- The control module detects a temperature difference between the ECT sensor and the IAT sensor of more than 15°C (27°F) and the time elapsed cranking the engine without starting is more than 5 seconds. OR
- The control module detects a temperature difference between the ECT sensor and the IAT sensor of more than 15°C (27°F). The vehicle must then be driven for 5 minutes over 40 km/h (25 mph). If the IAT sensor temperature decreases more than 5°C (9°F), an engine block heater was detected and the test is aborted. If the IAT sensor temperature does not decrease, an engine block heater was not detected and DTC P0116 will set.

P0128
The control module detects that the actual amount of accumulated air flow is more than the predicted amount of accumulated air flow before the ECT reaches 80°C (176°F).

ACTION TAKEN WHEN THE DTC SETS
DTCs P0116 and P0128 are Type B DTCs.

CONDITIONS FOR CLEARING THE MIL/DTC
DTCs P0116 and P0128 are Type B DTCs.

CIRCUIT/SYSTEM VERIFICATION
1. If the ignition has been OFF for 8 hours or more, the ECT and the IAT, should be within 11°C (20°F) of each other and also the ambient temperature. Turn ON the ignition, with the engine OFF, and use a scan tool to observe the IAT and the ECT sensor parameters.
2. Inspect the ECT sensor terminals for corrosion, and for engine coolant leaking through the sensor.
3. Use the scan tool to verify the proper operation of the engine cooling system fans.
4. Turn OFF the ignition.

CAUTION: Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap. Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.

5. Inspect the cooling system surge tank for the proper engine coolant level. Refer to Cooling System Leak Testing and Draining and Filling Cooling System (Static Fill LX9) Draining and Filling Cooling System (Vac-N-Fill) Draining and Filling Cooling System (Static Fill LZ9). Component Tests and General Diagnostics Service and Repair
6. Verify the proper heat range, and the operation of the thermostat. Refer to Thermostat Diagnosis. Symptom Related Diagnostic Procedures

IMPORTANT: A critical analysis of the operation of the thermostat is necessary, to properly diagnose these DTCs.

CIRCUIT/SYSTEM TESTING

P0116 Only
The vehicle should be OFF for at least 8 hours for the ECT and the IAT to be at ambient temperature. The vehicle should not have changed environments during this time.

1. Inspect for the following conditions:
- Inspect the cooling system coolant level.
- If low then refer to Loss of Coolant. Loss of Coolant
- Corrosion on the ECT terminals
- Improper or corroded terminals at the ECT harness connector
- Loose terminals in the ECT harness connector
- Inspect for the ECT sensor for leaking engine coolant internally through the sensor.

IMPORTANT: The cooling fans are commanded ON when certain ECT DTCs are set.

2. With the key ON, engine OFF, measure for 4.8-5.2 volts from the signal circuit of the ECT sensor to a good ground with a DMM.
- If not within 4.8-5.2 volts, test the ECT sensor signal circuit for high resistance, or for an intermittent and for a poor connection at the control module. If circuits test normal, replace the control module.
3. Measure for 4.8-5.2 volts from the signal circuit of the ECT sensor to the low reference circuit of the ECT sensor with a DMM.
- If not within 4.8-5.2 volts, test the ECT sensor low reference circuit for high resistance, or for an intermittent and for a poor connection at the control module.
- If circuits test normal, replace the control module.
4. Measure for 4.8-5.2 volts from the IAT signal circuit to a good ground with a DMM.
- If not within 4.8-5.2 volts, test the IAT signal circuit for a high resistance, or for an intermittent and for a poor connection at the control module. If circuits test normal, replace the control module.
5. Measure for less than 5 ohms of resistance from the low reference circuit of the IAT sensor to a good ground with a DMM.
- If more then 5 ohms, test the IAT low reference circuit for high resistance or for an intermittent and for a poor connection at the control module. If circuits test normal, replace the control module.
6. Observe and record the ambient air temperature of the vehicle environment using an accurate thermometer.
7. After the vehicle has been OFF for 8 hours, remove the mass air flow (MAF)/IAT sensor, and ECT sensor.
8. Place the sensors on a work surface away from any heat source. Allow the sensors to reach the ambient air temperature for 30-60 minutes.
9. Connect the MAF/IAT sensor and the ECT sensor to the electrical connector, but DO NOT install them. Insulate the sensors from any engine heat source.

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

10. Turn ON the ignition and take a snapshot of the Engine Data List with a scan tool. Refer to Scan Tool Snapshot Procedure. Component Tests and General Diagnostics
11. Observe the recorded IAT Sensor parameters from the scan tool. Compare the differences between the IAT Sensor parameter, and the ambient air temperature more than 8°C (14°F).
- If more than 8°C (14°F), replace the IAT sensor.
12. Review the snapshot data that was taken with the scan tool. Observe the ECT Sensor and IAT Sensor parameters with a scan tool for a difference of less than 15°C (27°F).
- If more than 15°C (27°F), replace the ECT sensor.

REPAIR INSTRUCTIONS
- Mass Airflow Sensor/Intake Air Temperature Sensor Replacement
- Engine Coolant Temperature Sensor Replacement
- Control Module References for ECM replacement, setup, and programming

REPAIR VERIFICATION
1. Clear the DTCs with a scan tool.
2. Turn OFF the ignition for 60 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.
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