GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Tracker - 4WD 🢒 Engine 🢒 Engine Cooling 🢒 DTC P0116

Circuit Description

The DTC P0116 Engine Coolant Temperature (ECT) Sensor Performance diagnostic checks the accuracy of the ECT sensor signal. The ECT sensor is a thermistor. A thermistor is a resistor whose value varies with the temperature. The electrical resistance of the ECT sensor is high when the coolant temperature is cold, and the resistance is low when the coolant temperature is warm. The ECT sensor is wired in series with a fixed resistor in the powertrain control module (PCM). The PCM applies 5 volts to the ECT sensor. The PCM monitors the voltage across the ECT sensor and converts the voltage into a temperature reading. The voltage measured by the PCM will be high when the coolant temperature is cold, and low when the coolant temperature is warm. A DTC P0116 may set if the ECT sensor voltage does not indicate that the engine coolant temperature has increased sufficiently during engine operation.

Conditions for Running the DTC
    • The engine has been running for at least 20 minutes.
    • The vehicle has been driven at speeds of 50 km/h (30 mph) or more at least once since engine start.

Conditions for Setting the DTC

Engine coolant temperature (as indicated by the ECT sensor) variation is less than the expected value.

Action Taken When the DTC Sets
    • The PCM illuminates the malfunction indicator lamp (MIL) after two consecutive ignition cycles in which the diagnostic runs with the fault active.
    • The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

Conditions for Clearing the MIL/DTC
    • The MIL turns OFF after three consecutively passing trips without a fault present.
    • A History DTC clears after 40 consecutive warm-up cycles without a fault.
    • Use the scan tool Clear DTC Information function.

Diagnostic Aids

Check for the following conditions:

    • If a DTC P0106 and a DTC P0121 are also set, the malfunction may be in the sensor ground circuit.
    • Check for the proper operation of the engine's cooling system, including the correct coolant level. Refer to Engine Fails To Reach Normal Operating Temperature in Engine Cooling.
    • A faulty thermostat that stays open slightly can cause a DTC P0116 to set in cold weather when the vehicle is started and let sit while warming up. Replace any suspect thermostat. Refer to Thermostat Diagnosis in Engine Cooling.
    • Use the Temperature vs Resistance table in order to evaluate the possibility of a shifted (incorrectly calibrated) ECT sensor. A shifted sensor could result in a DTC P0116. Refer to Temperature Versus Resistance .
    • Check for a faulty electrical connection to the PCM.

If the DTC P0116 is intermittent, driving the vehicle under the following conditions can verify whether the fault is present. Perform the scan tool Clear DTC Information function. Road test the vehicle while monitoring the DTC P0116 diagnostic on the scan tool under the Not Ran Since Code Cleared selection in the DTC Information menu. If a DTC P0116 appears in the Not Ran Since Code Cleared list, the P0116 diagnostic has not yet run. When the DTC P0116 does not appear in the Not Ran Since Code Cleared list, the P0116 diagnostic has run. If the MIL is NOT ILLUMINATED and there is no PENDING DTC Status in DTC Information, the P0116 diagnostic has passed. DTCs MUST BE CLEARED in order to view the CURRENT STATUS of the Not Ran Since Code Cleared list. DO NOT FORGET that the Not Ran Since Code Cleared list only indicates that the test has run, not whether the test passed or failed. The DTC Information screen must be checked for CURRENT or PENDING status, in order to determine the outcome of the diagnostic test involved.

An intermittent malfunction may be caused by a fault in the ECT sensor electrical circuit. Inspect the wiring harness and components for an intermittent condition. Refer to Intermittent Conditions .

Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Wiring Systems.

If you cannot duplicate a DTC P0116, the information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC was first set.

Test Description

The numbers below refer to the step numbers in the diagnostic table.

  1. The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and to store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

    2.

  2. This step checks for a faulty ECT sensor or ECT sensor circuit.

    3.

  3. This step checks the integrity of the ECT sensor input circuit.

    4.

  4. This step checks the integrity of the ECT sensor ground circuit.

    5.

  5. This step checks the integrity of the ECT sensor input circuit.

    6.

  6. A cooling system that prevents the engine from warming up properly and reaching the correct engine operating temperature within a specified time can cause a DTC P0116 to set. A thermostat that stays open slightly can cause a DTC P0116 to set.

    7.

  7. This step determines if DTC P0116 is the result of a hard failure or an intermittent condition.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Check for a DTC P0117 or DTC P0118 with a scan tool.

Is a DTC P0117 or DTC P0118 present?

--

Go to DTC P0117 or DTC P0118

Go to Step 3

3

  1. Measure the actual coolant temperature.
  2. Turn ON the ignition, leaving the engine OFF.
  3. Observe the ECT sensor parameter on the scan tool.

Is the ECT sensor value displayed near the actual coolant temperature?

--

Go to Step 11

Go to Step 4

4

  1. Disconnect the ECT sensor electrical connector.
  2. Observe the ECT sensor parameter on the scan tool.

Does the scan tool indicate the specified value?

-40 C (-40°F)

Go to Step 5

Go to Step 8

5

  1. Jump the ECT sensor input circuit and the ground circuit together at the ECT sensor harness connector.
  2. Observe the ECT sensor parameter on the scan tool.

Does the scan tool indicate the specified value?

119°C (246°F)

Go to Step 13

Go to Step 6

6

  1. Jump the ECT sensor input circuit to chassis ground.
  2. Observe the ECT sensor parameter on the scan tool.

Does the scan tool indicate the specified value?

119°C (246°F)

Go to Step 7

Go to Step 8

7

Repair the open or electrical resistance in the ECT sensor ground circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 14

Go to Step 9

8
  1. Turn OFF the ignition.
  2. Disconnect the PCM electrical connector C2.
  3. Check the ECT sensor input circuit for a short or high electrical resistance.
  4. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 14

Go to Step 9

9
  1. Check for a faulty connection at the PCM and the ECT electrical connectors.
  2. Repair as necessary.

Was a repair necessary?

--

Go to Step 14

Go to Step 10

10

Replace the PCM. Refer to Powertrain Control Module Replacement .

Is the replacement complete?

--

Go to Step 14

--

11

  1. Inspect the engine cooling system for any of the following conditions:
    2. • Faulty thermostat
    • Refer to Thermostat Diagnosis in Engine Cooling
    • Low coolant level
    • Incorrect coolant
    • Faulty cooling system operation--Refer to Engine Fails To Reach Normal Operating Temperature in Engine Cooling
  2. Repair as necessary.

Was a repair necessary?

--

Go to Step 14

Go to Step 12

12

  1. Perform the scan tool Clear DTC Information function.
  2. Operate the vehicle within the Freeze Frame conditions as specified.

Does a DTC P0116 set?

--

Go to Step 13

Go to Diagnostic Aids

13

Replace the ECT sensor. Refer to Engine Coolant Temperature Sensor Replacement .

Is the action complete?

--

Go to Step 14

--

14
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 15

Go to Step 2

15

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK