DTC P0117 or P0118
DTC P0117 or P0118 |
Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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DTC Descriptors |
DTC P0117 00
Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage
DTC P0118 00
Engine Coolant Temperature (ECT) Sensor Circuit High Voltage
Diagnostic Fault Information |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
Signal
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P0117 00
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P0118 00
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P0118 00
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-
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Low Reference
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-
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P0118 00
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-
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-
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Typical Scan Tool Data |
ECT Sensor
Circuit | Short to Ground | Open | Short to Voltage |
Operating Conditions:
Engine operating in closed loop.
Parameter Normal Range: -39 to +139°C (-38 to +282°F) Varies with coolant temperature. |
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Signal
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139°C (282°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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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 signal circuit and supplies a ground to the low reference circuit.
The following table illustrates the difference between temperature, resistance, and voltage:
ECT | ECT Resistance | ECT Signal Voltage |
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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The ignition is ON.
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The engine speed is greater than 1000 RPM.
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Conditions for Setting the DTC |
P0117
The ECM detects the ECT voltage is below the thresholdP0118
The ECM detects the ECT voltage is above the thresholdAction Taken When the DTC Sets |
DTCs P0117 and P0118 are Type B DTCs
Conditions for Clearing the DTC |
DTCs P0117 and P0118 are Type B DTCs
Diagnostic Aids |
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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 (ECT and IAT Sensor)
Temperature Versus Resistance (Exhaust Temperature Sensor)
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If the engine has sat overnight, the intake air temperature (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 may set a DTC.
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Reference Information |
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
Circuit/System Verification |
1. |
Let the engine run for 60 s. Check the DTC information with a scan tool. Diagnostic trouble codes P0117 and P0118 must not be activated.
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2. |
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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Circuit/System Testing |
1. |
Ignition OFF, disconnect the harness connector at the B34 Engine Coolant Temperature Sensor.
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2. |
Ignition OFF, test for less than 5 Ω between the low reference circuit terminal 2 and ground.
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3. |
If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
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4. |
Ignition ON, verify the scan tool ECT Sensor is at -40°C (-40°F).
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5. |
If greater than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
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6. |
Ignition ON, connect a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool ECT Sensor parameter is greater than 136°C (277°F). |
7. |
If less 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 Engine Control Module.
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8. |
If all circuits test normal, test or replace the B34 Engine Coolant Temperature Sensor.
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Component Testing |
Static Test
1. |
Ignition OFF, disconnect the harness connector at the B34 Engine Coolant Temperature Sensor.
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2. |
Test the resistance between the signal circuit terminal 2 and the low reference circuit terminal 1 at various ambient temperatures. Note the measured values. Compare those measurements to the
Temperature Versus Resistance (ECT and IAT Sensor)
Temperature Versus Resistance (Exhaust Temperature Sensor)
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3. |
If not within the specified range, replace the B34 Engine Coolant Temperature Sensor.
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Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Engine Coolant Temperature Sensor Replacement
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Control Module References
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