Honda

Have Honda Questions? Ask a Honda Repair Expert.

Ask an Expert,
Get an Answer ASAP!

Honda
This answer was rated:

my car is reading p2646 and p2647 which is vtec oil pressure

switch circuit low voltage and...
my car is reading p2646 and p2647 which is vtec oil pressure switch circuit low voltage and high voltage. What would cause that? How do i fix?
Show More
Show Less
Ask Your Own Honda Question
Answered in 17 minutes by:
1/15/2009
AutoTech08
AutoTech08, Workshop owner
Category: Honda
Satisfied Customers: 973
Experience: Diploma in Automotive Engineering, 30 years working experience.
Verified

Hi there,

 

What is the year, model and engine variant?

Ask Your Own Honda Question
Customer reply replied 8 years ago
2005 Honda Civic SI - K20A3

Hi,

 

Possible causes are low engine oil pressure due to :

1. Insufficient engine oil level.

2. Weak oil pump or clogged oil lines.

 

You would need to check the engine oil level, test oil pressure and VTEC switch circuit and operations, wireharness and PCM. to verify which is the cause.

Ask Your Own Honda Question
Customer reply replied 8 years ago
woulndt i get an oil light if it was oil pressure or something

Hi ,

 

Yes, if oil pressure is low, the indicator lamp should show, however if the switch is inaccurate, it might not show.

 

If the oil passage to the VTEC valves are clogged, oil pressure would not show anything.

Ask Your Own Honda Question
Customer reply replied 8 years ago
The effect it is having on the car is that while driving once i reach 4 grand the car sort of shuts down. I can no longer accelerate almost as if I reached the rev limiter or governor. It happens in every gear but is not consistent. When I start the car it happens in every gear or not at all. I changed the VTEC oil pressure switch and reset the ECU but it didnt solve the problem. Does this seem to coinside with what you think I should check?

Hi there,

 

The symptoms shows the VTEC valve is not operating and providing the fault code. Since the valve has been replaced, the next thing to check would be the oil pressurre at the valve and PCM.

 

DTC P2646: VTEC OIL PRESSURE SWITCH CIRCUIT LOW VOLTAGE

Special Tools Required.

 

Pressure gauge adapter 07NAJ-P07010A
A/T low pressure gauge w/panel 07406-0070300
A/T pressure hose 07406-0020201
A/T pressure hose, 2,210 mm 07MAJ-PY4011A
A/T pressure adaptor 07MAJ-PY40120
Oil pressure hose 07ZAJ-S5A0200

 

1. Turn the ignition switch OFF.

 

2. Check the engine oil level.

Is the level OK?

YES: Go to step 3.

NO: Adjust the engine oil to the proper level.

 

3. Turn the ignition switch ON (II).

4. Reset the ECM

5. Start the engine. Hold the engine speed at 3,000 RPM with no load (in neutral) until the radiator fan comes on, then let it idle.

6. Test-drive under following conditions: Accelerate in 1st gear to an engine over 5,000 RPM. Hold the speed for at least 2 seconds.

Is DTC P2646 indicated?

YES: Go to step 7.

NO: Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the VTEC oil pressure switch, the VTEC solenoid valve and the ECM.

7. Turn the ignition switch OFF.

8. Remove the VTEC oil pressure switch (A) and install the special tools as shown, then install the VTEC oil pressure switch (A) to the oil pressure gauge adapter (B).

NOTE: Install the part in the reverse or order of removal with a new O-ring.

 

graphic

 

9. Disconnect the VTEC solenoid valve 2P connector.

10. Start the engine. Hold the engine speed at 3,000 RPM with no load (in neutral) until the radiator fan comes on, then let it idle.

11. Attach the battery positive terminal to VTEC solenoid valve 2P connector terminal No. 2.

12. Start the engine, then connect the battery negative terminal to VTEC solenoid valve 2P connector terminal No. 1, and check the oil pressure at an engine speed of 3,000 RPM.

Is the oil pressure above 390 kPa (4.0 kgf/cm 2 , 57 psi)?

YES: Go to step 13.

NO: Inspect the VTEC solenoid valve

13. Disconnect the VTEC oil pressure switch 2P connector.

14. At VTEC oil pressure switch side, check for continuity between VTEC oil pressure switch terminals No. 1 and No. 2 in the condition of step 12.

 

graphic

 

Is there continuity?

YES: Replace the VTEC oil pressure switch.

NO: Go to step 15.

15. Turn the ignition switch OFF.

16. Disconnect the battery terminals from the VTEC solenoid valve terminal connector.

17. Disconnect ECM/PCM connector B (24P).

18. Check for continuity between ECM connector terminal B9 and body ground.

 

graphic

 

Is there continuity?

YES: Repair short in the wire between the ECM (B9) and the VTEC oil pressure switch.

NO: Go to step 19.

19. Check for continuity between VTEC solenoid valve 2P connector terminal No. 1 and body ground.

 

graphic

 

Is there continuity?

YES: Go to step 20.

NO: Repair open in the wire between the VTEC solenoid valve and G101.

20. Check for continuity between ECM connector terminal B15 and body ground.

 

graphic

 

Is there continuity?

YES: Repair short in the wire between the ECM (B15) and the VTEC solenoid valve.

NO: Go to step 21.

21. Connect the VTEC solenoid valve 2P connector terminal No. 2 and body ground with a jumper wire.

 

graphic

 

22. Check for continuity between ECM connector terminal B15 and body ground.

 

graphic

 

Is there continuity?

YES: Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.

NO: Repair open in the wire between the ECM (B15) and the VTEC solenoid valve.

 

 

 

 

 

 

 

 

 

 

AutoTech08
AutoTech08, Workshop owner
Category: Honda
Satisfied Customers: 973
Experience: Diploma in Automotive Engineering, 30 years working experience.
Verified
AutoTech08 and 87 other Honda Specialists are ready to help you
Ask your own question now
Ask AutoTech08 Your Own Question
AutoTech08
AutoTech08
AutoTech08, Workshop owner
Category: Honda
Satisfied Customers: 973
973 Satisfied Customers
Experience: Diploma in Automotive Engineering, 30 years working experience.

AutoTech08 is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Thank you very much for saving my daughter and her family a lot of money on her Honda. You are definitely on my list for future help. Thanks, again.

FredUSA

I just heard from my mechanic. You were right...a $45.00 job. THANK YOU!! Your response was received in less than 10 minutes!!

Linda B.USA

Your answers were clear and the diagrams were perfect. Dealer wanted $87 for an hour of labor and even I did it in 15 minutes.

EdUSA

HONDA PLATINUM was great. I really appreciate his help. I was ready to trade my new Honda until he told me to wait until I got 3,000 miles on it and my gas mileage would get much better.

SummerUSA

I took the Power Steering O-Ring service bulletin linked from JustAnswer to my Acura dealer, and not only did they no-charge the o-ring, they also replaced the power steering pump at no cost.

Gary RStevenson Ranch, CA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

< Previous | Next >

Meet the Experts:

Kyle N.

Kyle N.

Honda Master Tech

3,635 satisfied customers

Honda Dealer Tech, ASE Master Auto Tech

John G.

John G.

Honda Technician

2,643 satisfied customers

Dealership tech since 1982. ASE and Honda Master Technician.

Chris (aka-Moose)

Chris (aka-Moose)

Technician

511 satisfied customers

16 years of experience

Marty

Marty

Bosch Master Tech

123 satisfied customers

Bosch Certified Master Technician

Amedee

Amedee

Former ASE Master Technician

1,391 satisfied customers

ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector

Ron

Ron

ASE Certified Technician

381 satisfied customers

ASE Certified Tech 34 years.

thebesthonda

thebesthonda

ASE MasterTechnician

2,299 satisfied customers

26 years experience

< Previous | Next >

Related Honda Questions
2002 Honda Civic Si 2.0 cranks but will not start. Have fuel
yes changed the blue fuel pump relay near the computer, and the crankshaft position sensor … read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
A Honda mechanic I have a 1987 Honda Civic SI. It has this
Please a Honda mechanic I have a 1987 Honda Civic SI. It has this problem that after it is warmed up, thel idle will fluctuate between 1000 1250 RPM's. It had this problem when I first got it then dis… read more
MASTER TECH
MASTER TECH
Master Tech
Vocational, Technical or Trade Scho
4,807 satisfied customers
Cruise control not working 2002 Civic Si hatch, Not sure
Yes. Visual check on some fuses, but still not sure which ones I need to check. … read more
Honda-Man
Honda-Man
Associate Degree
3,131 satisfied customers
I replaced my starter on my 2007 honda civic si earlier
i replaced my starter on my 2007 honda civic si earlier today and when I took it for a test drive, it isnt going faster than 20 mph. It is also idling at 2500 … read more
Matt
Matt
Engineer
Bachelor\u0027s Degree
5 satisfied customers
Have an 04 civic si hatchback.Will a K20A2 out of RSX type S
Have an 04 civic si hatchback.Will a K20A2 out of RSX type S ,swap in ,w/o mods? Broke crank in motor. Cars at my mechanic shop, waiting to hear back from me ,on engine I'm sending. Almost forgot, 5 s… read more
BOBBYSS
BOBBYSS
TECHNICIAN/ADVISOR
Associate Degree
8,343 satisfied customers
I have a 2007 honda civic si 2 door. It has the 2.0L vtec
I have a 2007 honda civic si 2 door. It has the 2.0L vtec engine. My AC seized up and trying to find a smaller belt to put on so i can bypass the AC pulley til i can afford a new ac compressor. What b… read more
rpmdiag
rpmdiag
High school
7,114 satisfied customers
I looking for underhood / dimension honda civic si 2009,
i looking for underhood / dimension honda civic si 2009 … read more
Chris (aka-Moose)
Chris (aka-Moose)
Technician
Vocational, Technical or Trade School
511 satisfied customers
I have a 2006 honda civic si with a 2.0. It cranks but wont
I have a 2006 honda civic si with a 2.0. It cranks but wont start, has 50psi fuel pressure, good spark and has injector pulse. where do i start?… read more
rpmdiag
rpmdiag
High school
7,114 satisfied customers
2009 Honda Civic SI low compression after replacing clutch
2009 Honda Civic SI low compression after replacing clutch and flywheel, does the flywheel alignment have anything to do with the engine compression?… read more
Amedee
Amedee
Former ASE Master Technician
Vocational, Technical or Trade Scho
1,391 satisfied customers
Think i blew main fuse on 2013 civic si by installing
think i blew main fuse on 2013 civic si by installing battery backwards. csn/t figure how to get it out … read more
Honda-Man
Honda-Man
Associate Degree
3,131 satisfied customers
I have no power at all in my car, consistent, 2013 civic si,
got the battery tested. i recently put an aftermarket intake in the car which had me relocate the battery. i had to extend the negative battery terminal but i did it properly and checked continuity and everything was fine but still nothing … read more
baddad1
baddad1
technician
High School or GED
5 satisfied customers
I have a 2007 Honda civic si 2.0 AC is not working. all
I have a 2007 Honda civic si 2.0 AC is not working. all fuses are good and the green lights on the dash come on. there are no fans nor clutch engagement. However, if I ground the red wire at the compr… read more
Mechanic01
Mechanic01
1,151 satisfied customers
Keep replacing distributor. 1999 honda civic si. I am a
Yes i am a diesel mechanic and i have changed plugs wires cap rotors coil and icm … read more
MASTER TECH
MASTER TECH
Master Tech
Vocational, Technical or Trade Scho
4,807 satisfied customers
Second opinion] Have 2009 Honda Civic Si V-tech 2.0 Having
Second opinion] Have 2009 Honda Civic Si V-tech 2.0 Having trouble with setting the Valves put new timing chain (head sent out to Mach. shop) it's running but loudly and doesn't have any torque. pleas… read more
acramstr
acramstr
Shop foreman
Vocational, Technical or Trade Scho
4,234 satisfied customers
Have 2009 Honda Civic Si V-tech 2.0 Having trouble with
Have 2009 Honda Civic Si V-tech 2.0 Having trouble with setting the Valves put new timing chain (head sent out to Mach. shop) it's running but loudly and doesn't have any torque. please advise thank y… read more
Eric Gardner
Eric Gardner
Fleet Manager
Bachelor\u0027s Degree
233 satisfied customers
I have a 2002 Civic SI with a p1106. Honda just replaced my
I have a 2002 Civic SI with a p1106. Honda just replaced my Ecu with a new unit but code came back after a short drive...now what?… read more
David Gieswein
David Gieswein
Lead Technician
ASE Master certified
103 satisfied customers
My 2007 Honda civic si coupe has been having issues with
my 2007 Honda civic si coupe has been having issues with losing power throughout every gear. it just started recently. my clutch is still pretty tight, but when I shift into my gears I have basically … read more
DoctorD
DoctorD
Shop Owner
Vocational, Technical or Trade Scho
652 satisfied customers
Civic si passes emissions check engine light is on repair
civic si passes emissions check engine light is on repair shop says cat converter needs to be replaced? … read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x