• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
ECT Sensor Signal | P0117 | P0118 | P0118 | P0118 | P0116, P0128 |
Low Reference | -- | P0118 | P0118 | P0118 | P0128 |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine running at various operating conditions Parameter Normal Range: Varies with coolant temperature | |||
ECT Sensor | 150°C (302°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F) |
The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5V to the ECT sensor signal circuit and a ground for 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 time 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.
• | DTC P0112, P0113, P0117, P0118, P0128, P0502, P0503, P0601, P1621, or P2610 is not set. |
• | The vehicle has had a minimum ignition OFF time of 8 hours. |
• | The ignition is ON. |
• | The start-up IAT is warmer than -7°C (+19°F). |
• | The Fuel Level Sensor parameter is greater than 2.5 percent. |
• | This DTC runs once per ignition cycle within the enabling conditions. |
• | The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 30°C (54°F) warmer than the IAT sensor. |
OR |
• | The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 16°C (29°F) warmer than the IAT sensor, and the time spent cranking the engine is greater than 30 seconds when the fuel level is greater than 2.5 percent. |
OR |
• | The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 16°C (29°F) warmer than the IAT sensor. Then the vehicle must be driven for greater than 6 minutes and 40 seconds at greater than 24 km/h (15 mph). If the IAT sensor then decreases greater than 5°C (9°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. |
DTC P0116 is a Type B DTC.
DTC P0116 is a Type B DTC.
• | 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 Versus Resistance table. |
• | 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. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM. |
⇒ | If warmer than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K20 ECM. |
⇒ | If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM. |
Measure and record the resistance of the ECT sensor at various ambient temperatures, then compare those measurements to the Temperature Versus Resistance table.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |
• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
ECT Sensor Signal | P0117 | P0118 | P0118 | P0118 | P0116, P0119, P0128 |
Low Reference | -- | P0118 | P0118 | P0118 | P0119, P0128 |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine Running Parameter Normal Range: -39 to +120°C (-38 to +248°F) | |||
ECT Sensor | 143°C (289°F) | -40°C (-40°F) | -40°C (-40°F) |
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F) |
The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5V to the ECT sensor signal circuit and a ground for the low reference circuit.
The purpose of this diagnostic is 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 engine is OFF. If the required engine OFF time is met at start-up, the ECM will compare the temperature difference between the actual measured ECT and a calibrated ECT model. The information for this model is derived from the previous drive cycle and includes the accumulated mass air flow (MAF), the engine run time, the ambient air temperature and the ECT at the end of the drive cycle.
If the ECM detects that the temperature difference between the measured and modeled ECT is not within an acceptable operating range of each other, then the ECM will continue to run this diagnostic to determine if a block heater was active during the engine OFF time.
• | DTCs P0112, P0113, P0114, P0117, P0118, P0119, P0128, P0502, P0503, P0601, P1621, or P2610 is not set. |
• | The vehicle has had a minimum ignition OFF time of 8 hours. |
• | The engine is running. |
• | The start-up modeled ECT is colder than 50°C (+122°F). |
• | The previous accumulated MAF is greater than 6,000 grams. |
• | The previous engine run time is greater than 600 seconds. |
OR |
• | The vehicle has had a minimum ignition OFF time of 8 hours. |
• | The engine is running. |
• | The previous ECT at engine shutdown is warmer than 75°C (+167°F). |
• | The previous accumulated MAF is greater than 6,000 grams. |
• | The previous engine run time is greater than 600 seconds. |
• | This DTC runs once per ignition cycle within the enabling conditions. |
The ECM detects a temperature difference at initial power-up that indicates that the actual measured ECT is 10°C (18°F) greater than the modeled ECT, and an active block heater has not been detected.
DTC P0116 is a Type B DTC.
DTC P0116 is a Type B DTC.
• | 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. |
• | The ECM memory which includes the ignition OFF timer is maintained by battery power. If the ECM or the battery are disconnected for less than 15 seconds the proper operation of the ECM memory and the timer can be disrupted. Always disconnect these components for greater than 30 seconds. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information.
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM. |
⇒ | If warmer than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K20 ECM. |
⇒ | If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM. |
Measure and record the resistance of the ECT sensor at various ambient temperatures, then compare those measurements to the Temperature Versus Resistance table.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |