Replacement of Leaking VTEC Oil Pressure Switch on the 2003 Accord

Following the leak I had from the VTEC solenoid spool valve assembly which I aimed to repair by replacing the filter on the assembly (catch that DIY here), the leak continued. With the engine running and looking down at the VTEC spool valve assembly, I could just see the oil flowing slowly from the base of the VTEC oil pressure switch to the rear of the assembly.

VTEC oil pressure switch leak

Oil leak from VTEC oil pressure switch as seen from under the vehicle

My research online pointed to a worn VTEC oil pressure switch o-ring as the almost definite cause. I changed the o-ring in question, but the leak continued. I then felt this was because I used an aftermarket o-ring. I ordered for the OEM VTEC oil pressure switch o-ring from Honda and fitted that. That didn’t stop the leak either. With this, I turned my attention elsewhere. A quick feel of the junction between the metal and plastic parts of the VTEC oil pressure switch got oil on my finger. Voila!!! The leak was coming from this exact junction.

VTEC oil pressure switch leak

VTEC oil pressure switch leaking from the highlighted point

Enough of the history. Hope it helped. Its dirt time! For the purpose of making the procedure complete, I would address this DIY as though I hadn’t changed the o-ring for the switch earlier.

Materials: 22mm deep socket, ratchet with extension (30cm is more than adequate), 10mm socket or spanner, torque wrench (recommended, but won’t stop you from carrying out the repair if unavailable)

VTEC oil pressure switch

Materials for replacing VTEC oil pressure switch


1. Detach the electric connector of the VTEC pressure switch and the 2nd electrical connector attached to the VTEC solenoid spool valve assembly.

2. Using the 22mm deep socket, extension bar and ratchet, break the seal on the pressure switch, but leave it in place. This would make it easier for you to loosen the part when you remove the whole assembly from the cylinder head.

VTEC oil pressure switch

Breaking the seal of the VTEC oil pressure switch

NB: If you had recently replaced your VTEC oil pressure switch o-ring you can actually finish the procedure without bringing down the spool valve assembly. Simply take out the old part and continue with steps 7&9. If you are replacing the o-ring I advise bringing down the assembly to prevent dirt from getting into the groove for the pressure switch.

3. Remove the VTEC solenoid spool valve assembly from the cylinder head. All steps can be found in this earlier post

4. Remove the old VTEC oil pressure switch from the assembly.

5. Remove the old pressure switch o-ring from its groove and discard. If this is difficult to do by hand, use the curved tip of say a 1mm copper wire to remove the old o-ring.

Removing the VTEC oil pressure switch o-ring

Removing the old o-ring

VTEC pressure switch o-ring

Old & new o-ring. L-new, R-old. The old had flattened over time

6. Insert the new VTEC oil pressure switch o-ring in its groove.

 o-ring for VTEC

New VTEC oil pressure switch o-ring in place

7. Screw on the new part (PN: 37250-PNE-G01) by hand. I bought a used part from Mgbuka Obosi motor parts market. (Watch out for the post on buying good used parts!)

iVTEC pressure switch

Replacement switch. It came with the red OEM o-ring!

8. Refit the VTEC spool valve assembly onto the cylinder head (once again, steps are found in this previous post)

9. Torque the new VTEC oil pressure switch to 22Nm using the torque wrench and follow reverse steps.

Torquing VTEC oil pressure switch to 22Nm

Torquing VTEC oil pressure switch to 22Nm


  • Corey

    whats the torque on the oil pressure switch?

  • Onyeka

    Hello Bro! I have the same problem.. please where can I order the oring from? Crv 2004

    • You can get o-rings from where the markets in your area that sell car parts. Just take the old one along. This should work. However, if you have the bandwidth, you can check to order from the US.

  • MaryAnn Schostag

    I just had this same problem with my 2003 Honda Accord (diagnosed code P2646) replaced it and car is still doing jerking a 3000rpms and worse gas mileage than before replacing. Can anyone help me figure out what exactly the problem is?

    • Hello Maryann,

      Sorry to hear the issue with your car. One of the first steps in troubleshooting a P2646 code is to check oil level and it’s condition. A low oil level will give this code. Using wrong oil weights or going extended oil changes are also culprits. Often this code goes with just a simple oil change. However, see if any of the points highlighted above applies.
      Hope this helps. Do let me know how it goes or specific answers to the issues I mentioned to above.

  • Pingback: Help me ID this oil leak - Page 4 - Drive Accord Honda Forums

  • Malcolm

    So are there 2 o-rings that I should have? One going to the VTEC spool assembly (black) and one with the oil pressure switch itself (red)?

    • Thanks for being here Malcom. There’s just one o-ring. I didn’t use the red one in the picture. Once you insert the o-ring as shown in image 7, you screw on the VTEC oil pressure switch without any attached on it.

  • Steven

    Did this help with the leak?

    • Absolutely Steven!
      Prior to the replacement when I start the car and wait for about 30 secs, I would see the oil leaking out before my very eyes. That’s no more.

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