DTC P0117 or P0118 (LF1, LFW)
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DTC P0117 or P0118 (LF1, LFW)
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DTC P0117
Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage
DTC P0118
Engine Coolant Temperature (ECT) Sensor Circuit High Voltage
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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ECT Sensor Signal
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P0117
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P0118
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P0118*
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P0116
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Low Reference
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-
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P0118
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P0118*
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P0116
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* Sensor or ECM damage may occur if the circuit is shorted to B+
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ECT Sensor
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Circuit
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Short to Ground
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Open
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Short to Voltage
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Operating Conditions:
Engine operating in closed loop.
Parameter Normal Range:
-39 to 142 °C (-38 to 288 °F). Varies with coolant temperature.
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ECT Sensor Signal
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150°C (302°F)
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-40°C (-40°F)
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-40°C (-40°F)*
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Low Reference
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-
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-40°C (-40°F)
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-40°C (-40°F)*
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* Internal ECM or ECT sensor damage may occur if the circuit is shorted to B+
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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:
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ECT
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ECT Resistance
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ECT Signal Voltage
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Cold
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High
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High
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Warm
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Low
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Low
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Conditions for Running the DTC
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P0117
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•
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The engine is operating.
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•
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The start up intake air temperature (IAT) is less than 72°C (161°F).
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OR
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The start up intake air temperature (IAT) is greater than 72°C (161°F).
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The engine run time is greater than 59 s.
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The DTC runs continuously once the above conditions are met.
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P0118
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•
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The ignition is ON or the engine is operating.
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•
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The DTC runs continuously once the above condition is met.
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Conditions for Setting the DTC
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P0117
The ECM detects that the ECT is greater than 140°C (284°F) for greater than 1 s or a cumulative of 10 s.
P0118
The ECM detects that the ECT is less than -39°C (-38°F) for greater than 1 s or a cumulative of 10 s.
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Action Taken When the DTC Sets
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DTC P0117 and P0118 are Type B DTCs.
The ECM may activate the Cooling Fans at high speed.
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Conditions for Clearing the MIL/DTC
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DTC P0117 and P0118 are Type B DTCs.
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If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
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After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens.
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High resistance in the circuits of either the ECT or IAT sensor could set a DTC.
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DTCs must be cleared before Engine Cooling Fan's are Commanded Off.
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Schematic Reference
Engine Controls Schematics (3.0L (LF1))
Engine Controls Schematics (2.8L (LAU))
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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Engine idling for 1 min. Check the DTC information with a diagnostic tool. DTCs P0117 and P0118 should not set.
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2.
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Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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1.
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Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
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2.
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Warning
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Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.
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Note
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The control module or the sensor may be damaged if the circuit is shorted to battery positive voltage.
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Ignition Off, all vehicle systems Off, this can take up to 2 minutes. Check if there is less than 5Ω between the low reference circuit terminal A and ground.
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3.
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If greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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4.
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Ignition ON, verify that the scan tool ECT sensor parameter is at -40°C (-40°F).
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5.
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If greater than the specified range, test the signal circuit's pin B for a short to ground. If the circuit tests normal, replace the K20 ECM.
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6.
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Note
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If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
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Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the ECT sensor parameter is greater than 142°C (288°F).
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7.
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If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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8.
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If all circuits test normal, test or replace the B34 ECT sensor.
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1.
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Ignition OFF, disconnect the harness connector at the B34 engine coolant temperature (ECT) sensor.
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2.
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Note
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A thermometer can be used to test the sensor off the vehicle.
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Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the
Temperature Versus Resistance - Engine Coolant Temperature Sensor
table and verify that the resistance is within 5 % of the specification.
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3.
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If not within the specified range, replace the B34 ECT sensor.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
