2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1069

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