DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage. Cadillac Seville 2000

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2000 🢒 Seville 🢒 DTC 🢒 DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage

Engine Controls Component Views
Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The engine coolant temperature (ECT) sensor is a thermistor, or variable resistor, that measures the temperature of the engine coolant. The 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), DTC P0117 will set.

Conditions for Running the DTC

•	IAT sensor DTCs are not set.

•	The engine has been running for at least 10 seconds.

•	Intake air temperature is less than 70°C (158°F).

Conditions for Setting the DTC

•	The ECT sensor signal voltage is less than 0.08 volts. The temperature would be approximately 137°C (278°F).

•	The condition exists for less than 1 second.

Action Taken When the DTC Sets

•	The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.

•	The PCM stores the conditions present when the DTC set as Freeze Frame/Failure Records data.

Conditions for Clearing the MIL/DTC

•	The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.

•	The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

•	The DTC can be cleared by using the scan tool Clear DTC Information function.

Diagnostic Aids

For intermittent conditions, refer to DTC P1114 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage and/or Symptoms .

Step	Action	Values	Yes	No
1	Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Connect the scan tool. Turn ON the ignition with the engine OFF 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	Turn the ignition to the RUN position. Review and record the scan tool Fail Records data. Operate the vehicle within the Fail Records conditions. Using the scan tool, monitor the Specific DTC Information for DTC P0117 until the test runs. Does the scan tool indicate that DTC P0117 failed last test?	--	Go to Step 4	Go to Diagnostic Aids
4	Turn OFF the ignition. Disconnect ECT sensor connector. Turn OFF the ignition 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	Disconnect the PCM connector. Test the ECT sensor signal circuit for a short to chassis or ECT sensor ground. 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	Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete?	--	Go to Step 8	--
8	Review and record the scan tool Fail Records data. Operate the vehicle within the parameters listed in the Conditions for Running the DTC. Using the scan tool, monitor the Specific DTC Information for DTC P0117 until the test runs. Does the scan tool indicate that DTC P0117 passed?	--	System OK	Go to Step 2