6E1–215
X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
DIAGNOSTIC TROUBLE CODE (DTC) P1115 ENGINE COOLANT
TEMPERATURE (ECT) SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE
D06RX117
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
engine control module (ECM) applies a voltage (about 5.0
volts) through a pull–up resistor to the ECT signal circuit.
When the engine coolant is cold, the sensor (thermistor)
resistance is high, therefore the ECM will measure a high
signal voltage. As the engine coolant warms, the sensor
resistance becomes less, and the ECT signal voltage
measured at the ECM drops. With a fully warmed up
engine, the ECT signal voltage should measure about 1.5
to 2.0 volts. If the PCM detects an ECT signal that is
intermittently above the range of the ECT sensor,
Diagnostic Trouble Code P1115 will set. Diagnostic
Trouble Code P1115 is a type D code.
Conditions for Setting the DTC
D
Engine run time longer than 180 seconds.
D
The ECT sensor signal is intermittently greater than
–39
°
C (–38
°
F) (4.94 volts) for a total of 10 seconds
over a 100–second period.
Action Taken When the DTC Sets
D
The ECM will not illuminate the malfunction indicator
lamp (MIL).
D
The ECM will store conditions which were present
when the Diagnostic Trouble Code set as Failure
Records data only. This information will not be stored
as Freeze Frame data.
Conditions for Clearing the DTC
D
A history Diagnostic Trouble Code P1115 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.
D
Diagnostic Trouble Code P1115 can be cleared by
using the Scan Tool’s ”Clear Info” function.
Diagnostic Aids
Check for the following conditions:
D
Poor connection at ECM – Inspect harness connectors
for backed–out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal–to–wire connection.
D
Damaged harness – Inspect the wiring harness for
damage; shorts to ground, shorts to battery positive,
and open circuits. If the harness appears to be OK,
observe the ECT display on the Tech 2 while moving
connectors and wiring harnesses related to the ECT
sensor. A change in the ECT display will indicate the
location of the fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the Diagnostic Trouble Code to
be set occurs. This may assist in diagnosing the
condition.