2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1069
Circuit Description
The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module
(ECM) supplies 5 V to the ECT signal circuit and supplies a ground to the low reference circuit.
The following table illustrates the difference between temperature, resistance, and voltage:
Conditions for Running the DTC
P0117
* The engine is operating.
* DTC's P0116, P0118, or P0119 are not set.
* The start up intake air temperature (IAT) is less than 75掳C (167掳F).
* The difference between intake temperature (IAT) and intake air temperature at last engine shut down is less than 20掳C (70掳F).
* The engine run time is greater than 60 s.
* The DTC runs continuously once the above conditions are met.
P0118
* The engine is operating.
* DTC's P0116, P0117 or P0119 are not set.
* The start up intake air temperature (IAT) is less than 75掳C (167掳F).
* The difference between intake temperature (IAT) and intake air temperature at last engine shut down is less than 20掳C (70掳F).
* The DTC runs continuously once the above condition is met.
Conditions for Setting the DTC
P0117
The ECM detects that the ECT is greater than 140掳C (284掳F) for greater than 1 s or a cumulative of 10 s.
P0118
The ECM detects that the ECT is less than -39掳C (-38掳F) for greater than 1 s or a cumulative of 10 s.
Action Taken When the DTC Sets
DTC P0117 and P0118 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTC P0117 and P0118 are Type B DTCs.
Diagnostic Aids
* Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a
DTC or a driveability condition. Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor (See: Powertrain
Management/Computers and Control Systems/Specifications/Temperature Versus Resistance - Engine Coolant Temperature Sensor).
* If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3掳C (5掳F).
* After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens.
* High resistance in the circuits of either the ECT or IAT sensor could set a DTC.
Reference Information
Schematic Reference
Engine Controls Schematics (LAU) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
