DTC P0117 or P0118
Diagnostic Instructions
DTC Descriptors
DTC P0117: Engine Coolant Temperature (ECT)
Sensor Circuit Low Voltage |
DTC P0118: Engine Coolant Temperature (ECT)
Sensor Circuit High Voltage |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Signal
|
P0117 00
|
P0118 00
|
P0118 00
|
-
|
Low Reference
|
-
|
P0118 00
|
-
|
-
|
|
|
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.
|
Signal
|
139°C (282°F)
|
-40°C (-40°F)
|
-40°C (-40°F)
|
Low Reference
|
-
|
-40°C (-40°F)
|
-40°C (-40°F)
|
|
|
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
|
High
|
High
|
Warm
|
Low
|
Low
|
|
|
Conditions for Running the DTC
• |
The engine speed is greater
than 1 000 RPM. |
Conditions for Setting the DTC
P0117
The ECM detects the ECT voltage is below the threshold.
P0118
The ECM detects the ECT voltage is above the threshold.
Action 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
• |
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 . |
• |
If the engine has sat
overnight, the intake air temperature (IAT) sensor and the ECT
sensor values should display within 3°C (5°F). |
• |
After starting a cold engine,
the ECT sensor temperature should rise steadily, then stabilize
after the thermostat opens. |
• |
High resistance in the
circuits of either the ECT or IAT sensor may set a DTC.
|
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
1. |
Engine running for 60 s.
Observe the DTC information with a scan tool. DTCs P0117 and P0118
should not set. |
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 B34 Engine Coolant Temperature
Sensor. |
2. |
Ignition OFF, test for less
than 5 Ω between the low reference circuit terminal 2 and
earth. |
⇒ |
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. |
3. |
Ignition ON, verify the scan
tool ECT Sensor is at -40°C (-40°F). |
⇒ |
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. |
|
Caution: If
the fuse in the jumper wire opens, the signal circuit may have a
short to a voltage or a short to ground and the sensor might be
damaged. |
4. |
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). |
⇒ |
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. |
5. |
If all circuits test normal,
test or replace the B34 Engine Coolant Temperature Sensor.
|
Component Testing
Static Test
1. |
Ignition OFF, disconnect the
harness connector at the B34 Engine Coolant Temperature
Sensor. |
2. |
Test and record the resistance
between the signal circuit terminal 2 and the low reference circuit
terminal 1 at various ambient temperatures. Compare those
measurements to 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.
|