[sundog925]

Hey all.

Following this thread pretty closely.

I have a 09 automatic EX and its exhibiting everything mentioned here.

Ride was going as normal after getting the car out of the body shop and after utilizing cruise control as normal, going uphill, car shifts past 2500rpm and then suddenly cruise control disengages, CEL and VSA lights both come on with really bad dogging. Accelerating does nothing and had to pull off the side of the road. Made it work, then problem replicated after around 10 mins of driving, and stop and go at stop signs, seems to be happening around the 2000-2500rpm mark.

Took the car to auto zone, retrieved the codes:

-U0107 TAC MODULE COMMUNICATION (indicates the PCM did not receive a message from the throttle actuator control module within a predetermined period of time)

-P2646 VTEC OIL PRESSURE SWITCH CIRCUIT MALFUNCTION

Next, took it for an oil change, in which after the tech noted the CEL turned off and now I can't get the problem to replicate.
Very strange, still have an appointment with Honda on wednesday, will take the paper with me.

After reading through the thread, it seems it could be a variety of problems. So hopefully this was just a one-off.

 

[sundog925]

Follow Up:

Dealership did a diagnostic, was told the throttle body is malfunctioning and needs replacing. They were able to reproduce the problem they said, I wasn't able to since it started happening. Also, they only pulled U0107 from the car.

They quoted 1019$ for everything.

What made me uneasy was they unplugged my dash cam and put the wires in the glove box.

WTF? Why would they do that? Super suspect to me.

Luckily I know a reputable shop to do the work, don't trust the dealer now.

 

[bork]

I was getting good at coasting and cycling on & off also, but eventually that didn't work either. My last sensor so far has been ok now for a month. It was the old original I exercised with the air gun while checking continuity. The new sensor definitely showed sporadic readings.

Still running great since 4/8/2019! (even in heavy rain storm)

 

[RegalT]

Funny Im reading this today... E just threw the 2646 error this Morning... this will be the second time I am replacing this in two years. Why wasnt there more than just a Tech Bulletin on this... should have been a dam Recall... well there goes $100 and hours worth of work. last time the bolt striped on me and and it took all damn day.

 

[zebra007]

After I did a head gasket I went through this. I changed the oil and cleaned the screen and had it come back. Checked the screen again, it had some gunk on it, cleaned it again. The oil was very clean but I changed it again anyway. Problem went away. Still using original solenoid 200K+ miles. If the wire connector is not seated if will trigger the code. Not sure if it was mentioned but no one should be using any gasket sealer or anything on the body of the valve. There is an O-ring that works just fine. I'm not sure if the solenoid is grounded through the wires or the surfaces.

This seems like one areas OEM parts are worth the extra cost.

 

[theorangebrick]

Re: Malfunction Light and Code 2646




According to the service manual code 2646 is for rocker arm switch (VTEC oil pressure switch) low voltage.

This is second ele for me but first time with P2646. So here is what I did first. I checked all 3 screens. Don't forget the one behind the power steering. I was stumped all were clear. Then I checked voltage. Everything checked out. Code says VOLTAGE but instead I focused on what other mechanics told me....pressure. Ugh. Changed pressure sensor, spool valve assembly and still had limp mode at 2800rpms.Had 2 mechanics tell me to just sell it, "its a pressure problem" , both said the engine was done. I was willing to give up yet. Why? This happened out of the blue. I has just bought from a local. All records indicated dealer work was done on time so why would motor be blown? I wasn't buying it. Studied all this threads, talked to multiple Honda Techs, no one had anything different than what I had done...still limp mode. Ugh. On a fluke, I went back to the voltage verbiage in code manual. decided to change every single fuse in the fuse box under the hood as a start. Guess what?!!! She was back to running solid a few seconds later....but no yet consistently. Here was the pattern I noticed....process of elimination pointed to a 15amp fuse on the line with a 10amp. I am pretty sure its somehow related to the ECU but frankly everyone is calling it something different. If I pull that fuse and start car without a/c blower or radio on, she runs like a clock...80mph no issue no code. As soon as I shut her down for a few hours, I get the code again. So back again, I pull the fuse, wait a few seconds and put back in. I start with no a/c and radio....I go 80 miles at 75 mph 3.8rpms. No code. So, I don't have the EXACT solution yet but a partial one....it is voltage related and somehow to this 15amp fuse. Cost was under 2,00. I'd start there next time! In mean time anyone have any ideas on what the cause is? Could this be related to the ECU? What am I not doing correctly to reset? If it doesn't reset, could there be a relay issue?

 

[Xangryth]

Bear with me--I retired from Chrysler - industrial electrician at their Kokomo Indiana transmission plant. I used to get very peeved when a CNC gear cutting machine operator would get a low oil pressure fault of some sort- they would call ME, not a mechanic who works on oil pumps , solenoid valves and lines- I had to literally prove the pressure switch was working as designed before they would send out the mechanics to fix the cause of the LOW OIL PRESSURE-- ugh. I used to tell those operators- if the low oil pressure light came on in your car would you call an electrician?
So, I am going to assume the Vtec switch is either bad or it's good. Good, after installing a new one and the engine running issues continue, means it really is an oil pressure issue. A new oil and filter, cleaning screens helps with oil flow, but maybe a new oil pump is also needed. As bearing clearances increase in high mileage engines,oil pressure drops and I know from past experience 50 years ago- a new oil pump , with factory spec pressure will help overcome the bearing clearance issue. If you have ever sat in an old Chevy and watched the 40lbs of oil pressure on the direct reading pressure gauge drop to 10 lbs at idle, you quickly realize you have to fix the oil pressure problem. The individual who switched from 20 to 30 weight oil had success, because the heavier oil increased oil pressure. Installing a digital readout oil pressure gauge and monitoring it may help with troubleshooting the actual root cause of the fault in the camshaft system
Also, my previous HHR started to have ABS dash light faults- I noticed if I just turned the key to on, waited about 15 seconds and then started up, there were no codes. So, next I plugged in a digital voltage readout into the 12v dash socket- I discovered the battery voltage was about 12.2V after sitting overnight- 12.5 would more like normal. Not finding any current drain, I installed a new battery. Morning voltage was 12.7-12.8 volts and the abs faults went away. Always , first rule out a weak battery before you do anything else- make sure the frame ground is good too, if in doubt, add another one.
I would love to put that P2646 oil pressure switch on my old pressure calibrator at Chrysler and find out exactly what pressure it's faulting out at- a bad running engine sure seems to indicate low oil pressure to the cam's hydraulic controls- which means the switch is telling the truth.
Finally, if you had a real oil pressure gauge on the dash and noticed the 50 lbs of oil pressure from 5 years ago had dropped to 25-30 at 200,000 miles, the garage might address the low oil pressure. If putting in 5w-30 bumped up the oil pressure and fixed the Vtec fault, then everybody would want a real oil pressure gauge so they could monitor the health of their Element's engine. Used car lots would hate the factory for putting those real pressure gauges back on cars, as buyers could check the PSI number and bypass the good running car that showed low oil pressure= an indication the engine was near it's end of life.

added: my 2002 Chevrolet Avalanche 1500 I bought with 143,000 miles 3 months ago reads 40-45 lbs maximum pressure at 2000 rpm- a new engine would read 60lbs. So on my next oil change I am going to bump the oil weight up from 30 to 40 and see if my pressure increases-
Mark

 

[Xangryth]

I did some research on vtec oil pressure- forgive me, if this is a duplicate of previous posts--
from here-- http://www.ozhonda.com/forum/archive/index.php/t-40904.html

Testing:
Remove the single pin connector from the VTEC solenoid. Remove the 10mm bolt from the oil pressure test port on the solenoid. Attach the oil pressure gauge. Warm the motor up. Run the motor at 1000, 3000, and 5000 rpm, but do not run it at no load for mare than 1 minute. Oil pressure should be 7psi or less with the solenoid disconnected. Re connect the solenoid and run the same test. It should now be 57psi or more.
me- so its 57 psi minimum or the engine won't have the correct high speed power-



The following are used on both systems (VTEC and VTEC-E) to determine VTEC operations by the Engine Management Computer.
-Engine speed.
-Vehicle speed.
-Throttle position sensor output.
-Engine load measured by the MAP sensor.
-Coolant temperature.

Oil pressure really doesn’t determine when VTEC comes on, just whether or not it will come on.

Oil pressure (HOT):
-Idle 10-psi minimum
-3000RPM 50-psi minimum

and--
ECU-MAN
30-03-2006, 07:22 PM
VTEC need 25 to 30 psi to kick in, it wont be reliable unless you have a good 50 to 70 psi.

at idle you will want to have about 15- 30 psi
3000 rpm you would want around 55- 70 psi
and--
SKREMN
02-04-2006, 04:18 PM
ok I just increased my oil pressure now it drops down to 50psi rather then 40psi when vtec kicks in
I have only just driven it once since the change but it didnt drop out of vtec
on normal driving its about 65-70 psi
and idel about 25psi
so we are pretty simular now with our readings

Tinkerbell - have you inccraesed your oil pressure from stock? stock pump? stock tention on the piston spring?

I now have 3 washers on mine

me--so he adjusted the oil pump's relief pressure to increase the output oil pressure, which fixed his Vtec cam issue

 

[Ben10]

I went deep into this issue on my '03 element with 2646 and 2647 codes. One work around is to get a $20 code reader (OBII code reader) and by clearing the code, may get some temporary relief. I let my car warm up, turn off, clear the code, and I am usually able to drive but you'll see my case is more rare.

Reading all the forums, watching youtube. I called 10 different Honda dealerships in California to get advice on what to replace first (5 minute chats with the service advisor person), and did a mix of replaced stuff myself and paid a lot of money.

One forum had a former mechanic suggestions/fixes that are listed in order of common/easy and go to rare/harder/more expensive

1. change the oil
2. clean the screens
3. replace the oil pressure switch
4. replace the solenoid assembly * (crucial that it be Honda part not some other brand).
5. wiring issue could be the problem
6. engine sludge built up may be tripping the code
7. head gasket or engine cylinder issue.

Pro tip: I recognized that replacing the entire solenoid was a job I could easily do by watching youtube, buying the part from a honda dealership on ebay was only $30 more than the sensor and included it, and would take care of the screens the pressure switch and save me some time. So I went that route.

In my case, in the end, the issue 2647 was still there after I had done items 1-5. Because the head gasket (small part, but $1000 repair because you have to take the engine apart) has a small blow / leak. I used a head gasket sealer called k seal on my mechanics recommendation since my element is so old I don't want to put more $$$ into it if I can just get by. The code comes on after the element has sat for a while (cold start) and I just clear the code after it warms up, and I don't have any more issues that day. Not ideal, but has worked for me.

 

[Xangryth]

from 2010- troubleshooting the P2647-

P2647 Rocker Arm Actuator A Bank 1 Actuator Stuck On – TroubleCodes.net

www.troublecodes.net

--this guide was before the high mileage Element engines became common- what changed? Sludge- the oil passages in the head ( from the Vtec spool valve) have to pressurize the rocker arm switch over from low to high and back to low speed - if sludge narrows the oil passage , the timing will be off- the crank sensor tells the ECM that the valves should to be in a certain position ( that RPM)- feedback from the pressure switches confirm it is so or it isn't- if the pressure switch signal is wrong- the code is set. The two things that don't get addressed are - declining oil pressure due to age ( bearing wear and pump wear) and restricted oil passages in the head due to sludge- Electrical problems are easy to diagnose= it's either on or off-
if you tried zero weight oil, as an experiment and code didn't get set on startup, that would indicate , to me, sludge in the oil passageway- if switching to a higher weight oil fixes it, then I suspect the cause is declining oil pressure due to wear and tear of the engine. Supposedly, by dropping the pan, you can shim the relief valve to increase oil pressure by 5 lbs or so on startup- lacking historical, analog pressure readings, we don't know how much the pressure has dropped due to age. I keep looking for the Honda engineering pressure data that they used to set the system up- one other detail- I just had an epiphany- Eureka! ---the Honda oil pump is over driven by a larger drive gear to boost oil pressure at higher rpms- It might be POSSIBLE for the dealer mechanic , to increase the idle speed by say 100 rpm and maybe that would increase the oil pressure enough to fix the cold start Vtec trouble code- a working oil pressure readout would show, if 100rpm made a difference in pressure- BUT, rpm an change might also set other codes- ugh! Being an industrial electrician, if I had this problem on a machine, I would go into the program and tinker with the timing register- say it's 2 seconds after startup- I would increase it to 3 seconds and see what happens, then 4- it might be an easy fix, but sure not a money maker for the Honda dealer. I doubt the mechanics have the ability to modify the ECM program like that.
if that simple fix actually works- Honda should come out with a ECM flash update for higher mileage engines- However, knowing how engineering works in car companies, there is no money allocated for older - out of warranty/production K24 Element engine, plus the software may have changed in 10 years and all the programming software used to create the ECM program ( and modify it) for the old cars, went out the window with the old windows XP computers.
We must not forget, the goal of Honda is not to get that 200,000 engine in 2019 to 300,000 miles in 2029, but to get you to just trade old faithful in for a new Honda.

P2647 Rocker Arm Actuator A Bank 1 Actuator Stuck On – TroubleCodes.net

www.troublecodes.net

 

[Ben10]

from 2010- troubleshooting the P2647-

P2647 Rocker Arm Actuator A Bank 1 Actuator Stuck On – TroubleCodes.net

www.troublecodes.net

--this guide was before the high mileage Element engines became common- what changed? Sludge- the oil passages in the head ( from the Vtec spool valve) have to pressurize the rocker arm switch over from low to high and back to low speed - if sludge narrows the oil passage , the timing will be off- the crank sensor tells the ECM that the valves should to be in a certain position ( that RPM)- feedback from the pressure switches confirm it is so or it isn't- if the pressure switch signal is wrong- the code is set. The two things that don't get addressed are - declining oil pressure due to age ( bearing wear and pump wear) and restricted oil passages in the head due to sludge- Electrical problems are easy to diagnose= it's either on or off-
if you tried zero weight oil, as an experiment and code didn't get set on startup, that would indicate , to me, sludge in the oil passageway- if switching to a higher weight oil fixes it, then I suspect the cause is declining oil pressure due to wear and tear of the engine. Supposedly, by dropping the pan, you can shim the relief valve to increase oil pressure by 5 lbs or so on startup- lacking historical, analog pressure readings, we don't know how much the pressure has dropped due to age. I keep looking for the Honda engineering pressure data that they used to set the system up- one other detail- I just had an epiphany- Eureka! ---the Honda oil pump is over driven by a larger drive gear to boost oil pressure at higher rpms- It might be POSSIBLE for the dealer mechanic , to increase the idle speed by say 100 rpm and maybe that would increase the oil pressure enough to fix the cold start Vtec trouble code- a working oil pressure readout would show, if 100rpm made a difference in pressure- BUT, rpm an change might also set other codes- ugh! Being an industrial electrician, if I had this problem on a machine, I would go into the program and tinker with the timing register- say it's 2 seconds after startup- I would increase it to 3 seconds and see what happens, then 4- it might be an easy fix, but sure not a money maker for the Honda dealer. I doubt the mechanics have the ability to modify the ECM program like that.
if that simple fix actually works- Honda should come out with a ECM flash update for higher mileage engines- However, knowing how engineering works in car companies, there is no money allocated for older - out of warranty/production K24 Element engine, plus the software may have changed in 10 years and all the programming software used to create the ECM program ( and modify it) for the old cars, went out the window with the old windows XP computers.
We must not forget, the goal of Honda is not to get that 200,000 engine in 2019 to 300,000 miles in 2029, but to get you to just trade old faithful in for a new Honda.

P2647 Rocker Arm Actuator A Bank 1 Actuator Stuck On – TroubleCodes.net

www.troublecodes.net

Great article you linked

 

[Xangryth]

Great article you linked

Thanks--
asked the original owner of the 2005 Element I bought, if he had ever had any of these Vtec codes- he had not. It now has 234,000 miles- he put 150,000 miles on it in 5 years! Still uses 5-20 oil and claims the engine needs no oil between changes. I have a hunch that there is very little sludge in this motor and the piston rings aren't stuck in the grooves.

 

[okey0]

Hi all, new here due to the 2646 code. I replaced the VVT solenoid (part on backside of engine) a month ago, using a Gates part (VVS214) that i ordered from rockauto. the MIL went away immediately when this part was replaced-i didnt even have to reset the MIL. I did not do the screen cleaning that is located behind the power steering pump. Anyway, the element (2005) is in limp mode again, with code 2646 showing again. Soooooo, is it a defective Gates part, or do i really need to get in there and check that screen thats behind the power steering pump? I wouldnt think the code would be gone for a month if the screen was plugged? Also, what is the role of the oil control valve (pic below)

? It seems to be wired in with the VVT solenoid in some way, could this be causing the problem?

 

[Xangryth]

Visualize what happens when a heavy rain starts and the roof gutters fill with water- all is well, until the gutter outlet gets clogged with leaves- then the water begins overflowing the gutter. In like manner, the oil pathways going to and leaving your switch and solenoids could cause Vtec timing problems, if sludge has built up to a critical point, like a screen, or small drilled oil passageway to the valve rocker arm system..( I am assuming your oil pump is producing adequate oil pressure)
Ask Honda service if you can safely do an oil & filter change using 0-20W oil- a thinner weight oil will allow the Vtec system to operate easier on startup, to allow the engine to warm up, without setting a code. Synthetic oil has better sludge cleaning properties, too. If the code goes away, run 1000 miles and do an oil/ filter change again and go back to 5-20W synthetic. Then you will find out if the code stays away.
I am personally curious enough that I may someday build a test jig to measure the pressure settings on my V-tec pressure switch- and install a tee fitting, with a digital oil pressure meter tap, to measure the actual engine oil pressure of my engine.

 

[acendero]

Hello,

I had the same issue with my 05 element. Please check the following:

Locate the VTEC solenoid and check the connectors (They get corroded). Also, wiggle the cables back and forward. The black plastic rubber tends to shrink. Drive the car on the streets for some time. The check engine code will go away. Then drive it on the highway (THIS IS THE TRUE TEST)
If the problem persists, the connector itself is bad, "DONT WASTE YOUR TIME AT THE JUNKYARD NOR DEALER" You can get new connectors from aliexpress.

Search for "Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot"

I hope this helps. Since nobody at Honda could find my problem.

 

[Hammerheart]

Hello,

I had the same issue with my 05 element. Please check the following:

Locate the VTEC solenoid and check the connectors (They get corroded). Also, wiggle the cables back and forward. The black plastic rubber tends to shrink. Drive the car on the streets for some time. The check engine code will go away. Then drive it on the highway (THIS IS THE TRUE TEST)
If the problem persists, the connector itself is bad, "DONT WASTE YOUR TIME AT THE JUNKYARD NOR DEALER" You can get new connectors from aliexpress.

Search for "Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot"

I hope this helps. Since nobody at Honda could find my problem.

I've had the same issue but the fix for me was different. I thought it may be an issue with corrosion, but the only thing that worked for me was to increase the weight of the oil and add seafoam to it to clean out the top of the engine block.The previous owner replaced the solenoid completely and had the issue come back less than a week later... I am convinced that what was keeping mine from working was related to the oil pressure/viscosity itself... dunno... it's been working for about 2 months with no issues.


One thing to take note of... the windshield fluid sprayers can get leaky over time. I live in the rain forest and this means that a LOT of water gets through those little dudes and drips RIGHT ON TOP of the vtec solenoid... causing corrosion. So ya... that part seems to be getting screwed up by multiple things.

 

[Ben10]

Thanks--
asked the original owner of the 2005 Element I bought, if he had ever had any of these Vtec codes- he had not. It now has 234,000 miles- he put 150,000 miles on it in 5 years! Still uses 5-20 oil and claims the engine needs no oil between changes. I have a hunch that there is very little sludge in this motor and the piston rings aren't stuck in the grooves.

That is a lot of miles in a short time.

I talked to a friend who bought an engine with 60,000 on it and shipped it to himself for $800 and then changed it. Made me think if I have issues but want to keep my E, that's not the worst option.

 

[Ben10]

Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot

That's a great tip, not always the problem but if it is, so much better than what a lot of the mechanics have on hand.

Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot|Fuel Inject. Controls & Parts| - AliExpress

Cheap Fuel Inject. Controls & Parts, Buy Quality Automobiles & Motorcycles Directly from China Suppliers:Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot Enjoy ✓Free Shipping Worldwide! ✓Limited Time Sale ✓Easy Return.

www.aliexpress.com

 

[Xangryth]

That's a great tip, not always the problem but if it is, so much better than what a lot of the mechanics have on hand.

Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot|Fuel Inject. Controls & Parts| - AliExpress

Cheap Fuel Inject. Controls & Parts, Buy Quality Automobiles & Motorcycles Directly from China Suppliers:Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot Enjoy ✓Free Shipping Worldwide! ✓Limited Time Sale ✓Easy Return.

www.aliexpress.com

That's a great tip, not always the problem but if it is, so much better than what a lot of the mechanics have on hand.

Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot|Fuel Inject. Controls & Parts| - AliExpress

Cheap Fuel Inject. Controls & Parts, Buy Quality Automobiles & Motorcycles Directly from China Suppliers:Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot Enjoy ✓Free Shipping Worldwide! ✓Limited Time Sale ✓Easy Return.

www.aliexpress.com

That's a great tip, not always the problem but if it is, so much better than what a lot of the mechanics have on hand.

Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot|Fuel Inject. Controls & Parts| - AliExpress

Cheap Fuel Inject. Controls & Parts, Buy Quality Automobiles & Motorcycles Directly from China Suppliers:Oil Pressure Switch/ IAT ECT VTEC Sensor Connector Wire Harness Wiring Pigtail Plug For Honda Acura Civic Element Pilot Enjoy ✓Free Shipping Worldwide! ✓Limited Time Sale ✓Easy Return.

www.aliexpress.com

 

[Xangryth]

For those who want to play with the weight of their engine oil, I found the technical specs for our engine- up to 10W-40 oil is approved--

Honda K24A engine (K24Z, K24W, K24Y) | How good it is...

The difference between Honda K24A,K24Z, K24W and K24Y engines, their specs, problems and reasons. List of cars with these engines. How to build a powerful K24 turbo or non-turbo, ways of achieving 400 WHP and more.

mywikimotors.com