DTC Advanced Diagnostics: P2647 (K20C2) - Honda Civic FC/FK 2016-2021

DTC Advanced Diagnostics: P2647

DTC P2647:Rocker Arm Oil Pressure Switch Circuit High Voltage

General Description

Logic Decision	Rocker Arm Oil Pressure Switch
Logic Decision	’ON’	’OFF’
Rocker Arm Oil Control Solenoid Command 'ON'	Failure	Normal
Rocker Arm Oil Control Solenoid Command 'OFF'	Normal	Failure

The VTEC system activates the rocker arm oil control solenoid with a command from the powertrain control module (PCM), and it charges/discharges the hydraulic circuit of the VTEC mechanism that switches valve timing between Low and High. The PCM monitors oil pressure in the hydraulic circuit of the VTEC mechanism using the rocker arm oil pressure switch downstream of the rocker arm oil control solenoid. If there is a difference between the oil pressure condition in the hydraulic circuit determined by the PCM command and the oil pressure condition determined by the status of the rocker arm oil pressure switch, the system is considered faulty, and a DTC is stored.

Monitor Execution, Sequence, Duration, DTC Type

Execution	Once per driving cycle
Sequence	None
Duration	2.5 seconds or more
DTC Type	Two drive cycles, MIL on

Enable Conditions

Condition	Minimum	Maximum
12 volt battery voltage [BATTERY]	10.5 V	–
Other	At idle

[ ]: HDS Parameter

Malfunction Threshold

When the rocker arm oil control solenoid is OFF, the rocker arm oil pressure switch remains OFF.

Possible Cause

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

	Rocker arm oil control solenoid failure
	Rocker arm oil control solenoid VTS line open
	Rocker arm oil control solenoid VTS line short
	Rocker arm oil pressure switch failure
	Rocker arm oil pressure switch VTM line open
	Rocker arm oil pressure switch VTM line short
	Oil passage clogged

Confirmation Procedure

Operating Condition

Start the engine, and let it idle for at least 3 seconds.

With the HDS

Do the VTEC TEST in the INSPECTION MENU with the HDS.

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 and the freeze data 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, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.