DTC Advanced Diagnostics: P0116 (1.5L Engine)

DTC P0116:  Engine Coolant Temperature (ECT) Sensor 1 Circuit Range/Performance Problem

General Description 

Courtesy of HONDA, U.S.A., INC.

The powertrain control module (PCM) supplies voltage to the engine coolant temperature signal circuit (about 5 V) through a pull-up resistor. As the engine coolant cools, the engine coolant temperature (ECT) sensor 1 resistance increases, and the PCM detects a high signal voltage. As the engine coolant warms, the ECT sensor 1 resistance decreases, and the PCM detects a low signal voltage. If the ECT sensor 1 output voltage does not reach a set temperature after starting the engine and driving a set time, or when the difference between the ECT sensor 1 output voltage while driving and the output voltage of ECT sensor 1 after the engine has been stopped a certain length of time does not change a certain amount, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type 

Execution	Once per driving cycle
Sequence	None
Duration	36 minutes or more
DTC Type	Two drive cycles, MIL on

Enable Conditions 

Condition	Minimum	Maximum
Engine time after starting the engine	10 seconds	-
Fuel feedback	Other than during fuel cut-off operation
Other	With a completely cooled engine (one that has been off for at least 6 hours): Judgment is made after the engine has run for at least 36 minutes or been driven at least 4 miles (6 km), turn the vehicle to the OFF (LOCK) mode and wait for at least 10 seconds, then start and run again for at least 10 seconds.
	With a partially cooled engine (one that has been off for less than 6 hours): Judgment is made after the engine has run for at least 36 minutes or been driven at least 4 miles (6 km), turn the vehicle to the OFF (LOCK) mode and wait for at least 6 hours then start and run again for at least 10 seconds.

Malfunction Threshold 

Malfunction determination 1:

With a completely cooled engine (one that has been off for at least 6 hours):

When the change in coolant temperature after 36 minutes or more of running time or 4 miles (6 km) or more of driving distance is 18 deg.F (10 deg.C) or less, a malfunction is detected.

Malfunction determination 2:

With a partially cooled engine (one that has been off for less than 6 hours):

When the difference between the coolant temperature after 36 minutes or more of running time or 4 miles (6 km) or more of driving distance the coolant temperature after the engine has been off for 6 hours and then run for 10 seconds is 18 deg.F (10 deg.C) or less, a malfunction is detected.

Possible Cause 

Confirmation Procedure 

Operating Condition 

With a completely cooled engine (one that has been off for at least 6 hours).

• Start the engine, and let it idle for at least 36 minutes or drive for at least 4 miles (6 km).
• Turn the vehicle to the OFF (LOCK) mode for 10 seconds, then restart the engine and let it idle for at least 10 seconds.

With a partially cooled engine (one that has been off for less than 6 hours).

• Start the engine, and let it idle for at least 36 minutes or drive for at least 4 miles (6 km).
• Turn the vehicle to the OFF (LOCK) mode for 6 hours then restart the engine and let it idle for at least 10 seconds.

• Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details 

Conditions for setting the DTC 

When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC, the freeze data, and the on-board snapshot are stored.

Conditions for clearing the DTC 

The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.