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DTC P0117 or P0118

Diagnostic Instructions
    • 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.

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

ECT Sensor Signal

P0117 00

P0118 00

P0118 00*

-

Low Reference

-

P0118 00

P0118 00*

-

* Internal ECM or sensor damage may occur if the circuit is shorted to B+.

Typical Scan Tool Data

ECT Sensor

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Engine operating in closed loop.

Parameter Normal Range: Varies with ambient air temperature, within a range of -39 to +120°C (-38 to +248°F)

ECT Sensor Signal

150°C (302°F)

-40°C (-40°F)

-40°C (-40°F)*

Low Reference

-

-40°C (-40°F)

-40°C (-40°F)*

* Internal ECM or sensor damage may occur if the circuit is shorted to B+.

Circuit/System Description

The engine coolant temperature (ECT) sensor 1 is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 V to the engine coolant temperature (ECT) sensor 1 signal circuit and an ground for the low reference circuit.

The following table illustrates the difference between temperature, resistance, and voltage:

ECT

ECT resistance

ECT signal voltage

Cold

High

High

Warm

Low

Low

Conditions for Running the DTC

P0117 00

    • The ignition is ON or the engine is running.
    • The battery voltage is greater than 9 V.
    • The DTC runs continuously when the above conditions are met.

P0118 00

    • The engine run time is greater than 60 s.
    • The inlet air temperature (IAT) sensor is greater than 0°C (32°F).
    • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P0117 00

The ECM detects that the engine coolant temperature (ECT) sensor 1 signal is less than 0.27 V, which is warmer than 137°C (279°F) for greater than 2 s.

P0118 00

The ECM detects that the engine coolant temperature (ECT) sensor 1 signal is greater than 4.96 V, which is colder than -39°C (-38°F) for greater than 2 s.

Action Taken When the DTC Sets
    • DTCs P0117 00, and P0118 00 are Type B DTCs.
    • The cooling fans will be commanded ON.
    • The A/C compressor will be commanded OFF.

Conditions for Clearing the DTC

DTCs P0117 00, and P0118 00 are Type B DTCs

Diagnostic Aids

Note: The engine coolant temperature (ECT) sensor 1 is mounted on the engine and the engine coolant temperature (ECT) sensor 2 (radiator coolant temperature (RCT) sensor) is mounted on the radiator.

    • The engine coolant temperature gauge will display full cold when an ECT DTC sets.
    • After starting the engine, the engine coolant temperature (ECT) sensor 1 temperature should rise steadily, then stabilise after the thermostat opens.
    • Test the engine coolant temperature (ECT) sensor 1 at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Ignition ON, observe the ECT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions.
  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.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the B34A Evaporator Temperature Sensor 1.
  2. Ignition OFF for 90 s, test for less than 5 Ω between the low reference circuit terminal 2 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool ECT Sensor parameter is colder than -39°C (-38°F).
    4. ⇒If warmer 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.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT Sensor parameter is greater than 128°C (262°F).
    5. ⇒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 Engine Control Module.
  5. If all circuits/connections test normal, replace the B34A Engine Coolant Temperature Sensor 1.

Component Testing

Static Test

Measure and record the resistance of the B34A Engine Coolant Temperature Sensor 1 at various ambient temperatures, then compare those measurements to the Temperature Versus Resistance : IAT  → ECT table.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Engine Coolant Temperature Sensor Replacement : Thermostat Housing → Radiator
    • Control Module References for ECM replacement, setup, and programming
   


© Copyright Chevrolet. All rights reserved
   


© Copyright Chevrolet. All rights reserved