DTC Advanced Diagnostics: P2652
DTC P2652:Rocker Arm Oil Pressure Switch B (Bank 1) Stuck on

General Description
With VCM

Mode
PCM sends command to the rocker arm oil control solenoid
Rocker arm oil pressure switch
(detected oil pressure)
Solenoid A (Bank 1)
Solenoid B (Bank 1)
Solenoid A (Bank 2)
Switch A (Bank 1)
Switch B (Bank 1)
Switch A (Bank 2)
6 Cylinder Mode
(Low VTEC Range)
OFF
OFF
OFF
ON (low)
OFF (low)
ON (low)
6 Cylinder Mode
(High VTEC Range)
ON
OFF
ON
OFF (high)
OFF (low)
OFF (high)
3 Cylinder Mode
(3 Cylinders are paused)
OFF
ON
OFF
ON (low)
ON (high)
ON (low)

The variable cylinder management (VCM) system activates the rocker arm oil control solenoid B (bank 1) with a command from the powertrain control module (PCM), and it charges/discharges the hydraulic circuit of the cylinder pause VTEC system mechanism that pauses the intake and exhaust valves on the rear banks. The PCM monitors oil pressure in the hydraulic circuit of the VTEC mechanism using the rocker arm oil pressure switch B (bank 1) downstream of the rocker arm oil control solenoid B (bank 1). 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 B (bank 1), the system is considered faulty, and a DTC is stored.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status
Execution
Once per driving cycle
Sequence
None
Duration
5.0 seconds or more
DTC Type
One drive cycle, MIL on
OBD Status
PASSED/FAILED/NOT COMPLETED (STILL TESTING)

Enable Conditions
Condition
Minimum
Maximum
Elapsed time after starting the engine
2.0 seconds
–
Elapsed time after cylinder pausing
2.0 seconds
–
Elapsed time until VPS can be allowed its initial operation
5.0 seconds***
–
5.0 seconds****
Elapsed time after reversion from low oil pressure condition
5.0 seconds
–
Engine coolant temperature
[ECT SENSOR 1]
167 °F (75 °C)
–
Estimated rear WU-TWC (bank 1) temperature
1,022 °F (550 °C)
–
Estimated front WU-TWC (bank 2) temperature
–
1,562 °F (850 °C)
Estimated front WU-TWC (bank 2) seal mat temperature
–
1,562 °F (850 °C)
Engine speed
[ENGINE SPEED]
1,250 rpm
3,300 rpm
Engine speed [ENGINE SPEED] that can be operated in VPS by uncontrolled the oil pressure
510 rpm*****
–
1,320 rpm******
Oil pressure
83 kPa (0.9 kgf/cm2, 12.1 psi)
–
Vehicle speed
[VEHICLE SPEED]
12 mph (19 km/h)
–
Fuel feedback
Closed loop at stoichiometric
Throttle position
Other than wide open throttle
Other than fully closed
Monitoring priority
P0139, P0159, P0401, P2A00, P2A03
No active DTCs set (prevents monitor from running)*1
P2649, P2654
No active DTCs set (prevents monitor from running)*2
P2654
***: When starting the engine at an engine coolant temperature [ECT SENSOR 1] is 68 °F (20 °C)
****: When starting the engine at an engine coolant temperature [ECT SENSOR 1] is 176 °F (80 °C)
*****: When the engine coolant temperature [ECT SENSOR 1] is 172 °F (78 °C)
******: When the engine coolant temperature [ECT SENSOR 1] is 221 °F (105 °C)
*1:
 
'13
 
*2:
 
'14-17
 

Malfunction Threshold
When the rocker arm oil control solenoid B (bank 1) is OFF, the rocker arm oil pressure switch B (bank 1) remains ON.

Logic Decision
Rocker Arm Oil Pressure Switch B (Bank 1)
ON
OFF
Rocker Arm oil Control Solenoid B (Bank 1) Command
ON
Normal
Failure (P2651)
OFF
Failure (P2652)
Normal

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 B (bank 1) stuck
Rocker arm oil pressure switch B (bank 1) failure
Rocker arm oil pressure switch B (bank 1) VCMSW line short
Rocker arm oil control valve failure
Oil passage clogged

Confirmation Procedure
Operating Condition

1.
Start the engine. Hold the engine speed [ENGINE SPEED] at 3,000 rpm without load (in P or N) until the radiator fan comes on.
2.
Let the engine idle for at least 5 seconds.
3.
Drive the vehicle on a flat road in 4th gear at a steady speed of 12 mph (19 km/h) or more at a steady engine speed [ENGINE SPEED] between 1,250 - 3,300 rpm for at least 5 seconds.
Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
Select the VTEC+VCM TEST in the INSPECTION MENU with the HDS, then select the CDVEB TEST with the HDS.

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.

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 battery.