GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2001 🢒 Eldorado 🢒 Engine 🢒 Engine Controls - 4.6L 🢒 DTC P0117

Circuit Description

The engine coolant temperature (ECT) sensor is a thermistor, or variable resistor, that measures the temperature of the engine coolant. The powertrain control module (PCM) supplies 5 volts to the ECT signal circuit through a pull-up resistor. When the engine coolant temperature is cold, the sensor resistance is high. When the engine coolant temperature increases, the sensor resistance lowers. 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, a high temperature indication, this diagnostic trouble code (DTC) will set.

Conditions for Running the DTC
    • DTCs P0112, P0113, P1111, or P1112 are not set.
    • The engine has been running for at least 10 seconds.
    • The intake air temperature (IAT) is less than 70°C (158°F).

Conditions for Setting the DTC
    • The ECT sensor temperature is more than 149°C (300°F) for longer than 10 seconds.
    • The condition exists for less than 1  second.

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

For intermittent conditions, refer to Intermittent Conditions .

Step

Action

Values

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

  1. Connect the scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. View the ECT sensor display.

Does the scan tool indicate an engine coolant temperature more than the specified value?

125°C (257°F)

Go to Step 4

Go to Step 3

3
  1. Turn the ignition to the RUN position.
  2. Review and record the scan tool Failure Records data.
  3. Operate the vehicle within the Failure Records conditions.
  4. Using the scan tool, monitor the Specific DTC Information for DTC P0117 until the test runs.

Does the scan tool indicate that the DTC P0117 failed last test?

--

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn OFF the ignition.
  2. Disconnect the ECT sensor connector. Refer to Engine Coolant Temperature Sensor Replacement .
  3. Turn ON the ignition, with the engine OFF.

Does the scan tool indicate an engine coolant temperature near the specified value?

-40°C (-40°F)

Go to Step 6

Go to Step 5

5

  1. Disconnect the PCM connector. Refer to Powertrain Control Module Replacement .
  2. Test the ECT sensor signal circuit for a short to chassis or the ECT sensor ground.
  3. If the condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 7

6

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

Is the action complete?

--

Go to Step 8

--

7

Replace the PCM. Refer to Powertrain Control Module Replacement .

Is the action complete?

--

Go to Step 8

--

8
  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 9

Go to Step 2

9

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

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

--

Go to the Diagnostic Trouble Code (DTC) List

System OK