DTC P1115 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage. Oldsmobile Intrigue 2000

For 1990-2009 cars only

Makes 🢒 Oldsmobile 🢒 2000 🢒 Intrigue 🢒 Engine 🢒 Engine Controls - 3.5L 🢒 DTC P1115 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Refer to Engine Controls Schematics

A/C Pressure Switch, TPS, MAP, ECT and IAT

Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Engine Controls Component Views
Powertrain Control Module Description
Heated O2 Sensors
Fuel Injectors
OBD II Symbol Description Notice
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Circuit Description

The engine coolant temperature (ECT) sensor contains a semiconductor--a device that changes resistance based on temperature. The ECT sensor has a signal circuit and a ground circuit. The PCM applies voltage of about 5.0 volts to the sensor on the signal circuit. The powertrain control module (PCM) monitors any voltage changes caused by changes in the resistance of the sensor, and uses this information to determine the engine coolant temperature.

When the engine coolant is cold, the sensor resistance is high, and the PCM signal voltage is only pulled down a slightly through the sensor to ground. The PCM, therefore, senses a high signal voltage or a low coolant temperature. When the engine coolant is warm, the sensor resistance is low, and the signal voltage is pulled down a greater amount. This causes the PCM to sense a low signal voltage or a high temperature.

Conditions for Running the DTC

The engine has been running for longer than 15 seconds.

Conditions for Setting the DTC

The ECT sensor intermittently indicates a coolant temperature of more than 134°C (274°F).

Action Taken When the DTC Sets

•	The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.

•	The malfunction indicator lamp (MIL) will not illuminate.

•	The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

Conditions for Clearing the MIL/DTC

•	A History DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.

•	The current DTC will clear when the diagnostic runs and does not fail.

•	Use a scan tool in order to clear the MIL diagnostic trouble code.

•	Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Powertrain Control Module Description , Clearing Diagnostic Trouble Codes.

Diagnostic Aids

Notice: Use the connector test adapter kit J 35616-A for any test that requires probing the following items:

•	The PCM harness connectors

•	The electrical center fuse/relay cavities

•	The component terminals

•	The component harness connector

Using this kit will prevent damage caused by the improper probing of connector terminals.

Check for the following conditions:

•	A faulty connection at the PCM -- Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

•	A damaged harness -- Inspect the wiring harness for damage. If the harness appears to be OK, observe the ECT display on the scan tool while moving connectors and wiring harnesses related to the ECT sensor. A change in the ECT display will indicate the location of the malfunction.

•	A skewed or incorrectly calibrated ECT sensor -- Refer to Temperature Versus Resistance .

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.

If the problem is intermittent, refer to Intermittent Conditions .

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	Select DTC info, Last Tst Fail and note any other DTCs set. Is DTC P0118 also set?	--	Go to DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage	Go to Step 3
3	Is DTC P1106, P1111, and/or P1121 also set?	--	Go to Step 8	Go to Step 4
4	Check for a faulty sensor ground circuit terminal connection at the ECT sensor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. If a problem is found, repair as necessary. Refer to Wiring Repairs or Connector Repairs in Wiring Systems. Was a problem found and corrected?	--	Go to Step 10	Go to Step 5
5	Check for a faulty ECT signal circuit terminal connection at the ECT sensor. Testing for Intermittent Conditions and Poor Connections in Wiring Systems. If a problem is found, repair as necessary. Refer to Connector Repairs or Wiring Repairs in Wiring Systems. Was a problem found and corrected?	--	Go to Step 10	Go to Step 6
6	Check the ECT signal circuit between the ECT sensor connector and the PCM for an intermittent open. Testing for Intermittent Conditions and Poor Connections in Wiring Systems. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems. Was a problem found and corrected?	--	Go to Step 10	Go to Step 7
7	Check the ECT signal circuit between the ECT sensor connector and the PCM for an intermittent short to voltage. Testing for Intermittent Conditions and Poor Connections in Wiring Systems. If a problem is found, repair as necessary. Refer to Refer to Wiring Repairs in Wiring Systems. Was a problem found and corrected?	--	Go to Step 10	Go to Step 8
8	Check for a faulty sensor ground circuit terminal connection at the PCM. Testing for Intermittent Conditions and Poor Connections in Wiring Systems. If a problem is found, repair as necessary. Refer to Connector Repairs or Wiring Repairs in Wiring Systems. Was a problem found and corrected?	--	Go to Step 10	Go to Step 9
9	Check for an intermittent open in the sensor ground circuit. Testing for Intermittent Conditions and Poor Connections in Wiring Systems. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems. Was a problem found and corrected?	--	Go to Step 10	Go to Diagnostic Aids
10	Clear the DTCs with the scan tool. Turn the key to OFF and wait 15 seconds. Operate the vehicle within the conditions that are required for this diagnostic to run. Refer to the Conditions for Running the DTC. Does the scan tool indicate that this test ran and passed?	--	Go to Step 11	Go to Step 2
11	Review the Captured Info using the scan tool. Are there any DTCs that have not been diagnosed?	--	Go to the applicable DTC table	System OK