2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 1763
DTC P0116
- Engine Coolant Temperature (ECT) Sensor Performance
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System 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 sensor signal circuit, and supplies a ground to the low reference circuit. The ECM uses this high side coolant
rationality diagnostic to determine if the input from the ECT sensor is skewed warmer than normal. The internal clock of the ECM will record the
amount of time the ignition is OFF. If the calibrated ignition OFF timer is met at start-up, the ECM will compare the temperature difference
between the ECT and the intake air temperature (IAT), to determine if the temperatures are within an acceptable operating range of each other.
Conditions for Running the DTC
* DTCs P0112, P0113, P0117, P0118, P0502, P0503, P0601, P0603, P062F, P2610 are not set.
* The vehicle has had a minimum ignition OFF time of 8 h.
* The ignition is ON.
* The start-up IAT is greater than -7掳C (+19掳F).
* The Fuel Level Sensor is greater than 5 %.
* This DTC runs once per cold start when the above conditions are met.
Conditions for Setting the DTC
* The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 30掳C (54掳F) greater than the IAT sensor.
OR
* The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 10掳C (18掳F) greater than the IAT sensor, and the
time spent cranking the engine is greater than 10 s, when the fuel level is greater than 5 %.
OR
* With the power-up IAT more than -7掳C (+19掳F), the ECM detects a temperature difference at power-up that indicates that the ECT sensor is
20掳C (36掳F) greater than the IAT sensor. Then the vehicle must be driven for more than 6 min and 40 s at greater than 40 km/h (25 mph). If
the IAT sensor then decreases greater than 4掳C (7掳F), an engine block heater was detected and the test is aborted. If the IAT sensor does not
decrease, an engine block heater was not detected and DTC P0116 will set.
Action Taken When the DTC Sets
DTC P0116 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0116 is a Type B DTC.
Diagnostic Aids
* The use of non-thermostatically controlled aftermarket block heater will cause this DTC to set.
* Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the
sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is
interpreted by the ECM as a warmer ECT.
* An IAT sensor that is skewed colder at various ambient temperatures due to greater resistance than is normal will increase the range between
these two sensors. Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to
the Temperature vs Resistance table. Refer to Temperature Versus Resistance (See: Powertrain Management/Computers and Control
Systems/Specifications/Temperature Versus Resistance).
* A slight to moderate resistance in the IAT sensor signal circuit or low reference circuit will increase the range between these two sensors.
This condition results in a greater voltage on the IAT sensor signal circuit, which is interpreted by the ECM as a colder IAT.
