DTC P0117 or P0118 - LDE
Diagnostic Instructions
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
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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
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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)
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-40°C (-40°F)
|
-40°C (-40°F)*
|
|
Low Reference
|
-
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-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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- If the ignition has been OFF for 8 h or greater,
the inlet air temperature, ambient air temperature, and the engine
coolant temperature (ECT) sensor 1 should be within
9°C (16°F) of each other. Ignition ON, observe the
scan tool IAT Sensor, Ambient Air Temperature, and the ECT
Sensor 1 parameters. Compare those sensor parameters to each
other to determine if the condition is current.
- Engine running, observe the ECT Sensor 1
parameter. The reading should be between -39 to
+120°C (-38 to +248°F) depending on the current
ambient air temperature, the engine run time, and the vehicle
operating conditions.
- 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
- Ignition OFF, disconnect the harness connector at the
B34 Engine Coolant Temperature Sensor.
- Ignition OFF, test for less than 5 Ω between the
low reference circuit terminal 2 and ground.
| ⇒ |
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. |
- Ignition ON, verify the scan tool ECT Sensor 1 is
at -40°C (-40°F).
| ⇒ |
If warmer than the specified value, test the
signal circuit terminal 1 for a short to ground. If the
circuit tests normal, replace the K20 Engine Control
Module. |
Note: If the fuse in the jumper
wire opens, the signal circuit is shorted to a voltage and the
sensor may be damaged.
- Install a 3 A fused jumper wire between the
B34 Engine Coolant Temperature Sensor signal circuit
terminal 1 and ground. Verify the scan tool ECT Sensor 1
is greater than 149°C (300°F).
| ⇒ |
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. |
- If all circuits test normal, test or replace the
B34 Engine Coolant Temperature Sensor.
Component Testing
Static Test
- Ignition OFF, disconnect the harness connector at the
B34 Engine Coolant Temperature Sensor.
- Test the B34 Engine Coolant Temperature Sensor by
varying the sensor temperature while monitoring the sensor
resistance. Compare the readings with the
Temperature Versus Resistance table and verify that the
resistance is within 5% of the specification.
| ⇒ |
If not within the specified range, replace the
B34 Engine Coolant Temperature Sensor. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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