DTC P0116 - LLU
Diagnostic Instructions
DTC Descriptor
DTC P0116 00: Engine Coolant Temperature
(ECT) Sensor Performance
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Signal Circuit
|
P0117 00
|
P0118 00
|
P0118 00*
|
P0116 00
|
Low Reference
|
-
|
P0118 00
|
P0118 00*
|
P0116 00
|
*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
coolant temperature
|
Signal
|
150°C (302°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
sensor signal circuit and a ground for the low reference
circuit.
The purpose of this diagnostic is to determine if the input from
the ECT sensor is skewed warmer than normal. The internal clock of
the ECM will record the amount of time the engine is OFF. If the
required engine OFF time is met at startup, the ECM will compare
the temperature difference between the actual measured ECT and a
calibrated ECT model. The information for this model is derived
from the previous drive cycle and includes the accumulated mass air
flow (MAF), the engine run time, the ambient air temperature
and the ECT at the end of the drive cycle.
If the ECM detects that the temperature difference between the
measured and modelled ECT is not within an acceptable operating
range of each other, then the ECM will continue to run this
diagnostic to determine if a block heater was active during the
engine OFF time.
Conditions for Running the DTC
• |
DTCs P0112 00, P0113 00,
P0117 00, P0118 00, and P2610 00 are not set. |
• |
The ignition has been off for longer than 8 h
before the engine is started. |
• |
This DTC runs once per ignition cycle when the
above conditions are met. |
Conditions for Setting the DTC
The ECM does not detect an ECT sensor change of greater than
10.5°C (50.9°F) within a calibrated time.
Action Taken When the DTC Sets
DTC P0116 00 is a Type B DTC.
Conditions for Clearing the DTC
DTC P0116 00 is a Type B DTC.
Diagnostic Aids
• |
Inspect the ECT sensor terminals for corrosion and
for engine coolant leaking through the sensor. Engine coolant that
is leaking through the sensor will create a high resistance short
to ground. This condition results in less voltage on the ECT sensor
signal circuit, which is interpreted by the ECM as a warmer
ECT. |
• |
An inlet air temperature (IAT) sensor that is
biased colder at various ambient temperatures due to greater
resistance than is normal will increase the range between these two
sensors. Measure and record the resistance of the IAT sensor at
various ambient temperatures, then compare those measurements to
the Temperature vs. Resistance table. Refer to
Temperature Versus Resistance . |
• |
Test the ECT sensor at various temperature levels
in order to evaluate the possibility of a biased sensor. A sensor
that is biased warmer can result in a driveability condition. Refer
to
Temperature Versus Resistance . |
• |
A slight to moderate resistance in the IAT sensor
signal circuit or low reference circuit will increase the range
between these two sensors. This condition results in a greater
voltage on the IAT sensor signal circuit, which is interpreted by
the ECM as a colder IAT. |
• |
If the condition is intermittent, allow the
vehicle to cool down for greater then 8 h with the ignition
off, may help isolate the condition. Compare the scan tool Radiator
Coolant Temperature Sensor and ECT Sensor temperature sensor values
at ignition on. The Radiator Coolant Temperature Sensor and the ECT
Sensor parameters should display within 3°C (5°F). |
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
- Ignition on, observe the DTC information with a scan
tool. Verify that DTC P0112 00, P0113 00, P0117 00,
or P0118 00 are not set.
- Ignition off, inspect the cooling system surge tank
for the proper coolant level. Refer to
Loss of Coolant and
Cooling System Draining and Filling .
- If the ignition has been OFF for 8 h or greater,
the B75B Mass Air Flow/Intake Air Temperature
Sensor (IAT 1), the B111 Turbocharger Boost
Sensor (IAT 2), and the B34A Engine Coolant
Temperature Sensor 1 should be within 9°C (16°F)
of each other and also the ambient temperature. Ignition ON,
observe the scan tool IAT Sensor, IAT Sensor 2 and the ECT
Sensor parameters. Compare those sensor parameters to each other
and also to the ambient temperature to determine if the ECT sensor
is skewed.
Note: Depending on ambient
temperature, it may take up to 4 min for the temperature to
equalise.
- Engine running, 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.
- Operate the vehicle within the conditions for running
the DTC. 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
B34A Evaporator Temperature Sensor 1.
- Inspect the B34A Engine Coolant Temperature
Sensor 1 terminals for corrosion and for engine coolant
leaking through the sensor.
- Ignition OFF for 1 min, 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 parameter
is colder than -39°C (-38°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. |
- 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 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
B34A Engine Coolant Temperature Sensor 1.
Component Testing
Static Test
- Ignition off, disconnect the harness connector at the
B34A Engine Coolant Temperature Sensor 1.
Note: A thermometer can be used
to test the sensor off the vehicle.
- Test the B34A Engine Coolant Temperature
Sensor 1 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
B34A Engine Coolant Temperature Sensor 1. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|