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“Legendary” p2646 code. Curious and Confused as can be.
so ima start this off by saying I’m new to cars and engines and all that type of knowledge but I’d say I got a grasp on things in passed year or 2 with it after doing some learning. I bought a 2005 Honda accord 2.4l LX-g with 260k kms(idk if G means anything). At the time of sale there was no codes or anything popping up.
I’m now assuming that upon the sale he went and erased any codes or anything because I took my Autel AutoLink AL619 OBD2 Scanner with and no stored or pending codes.
Then I was driving the car to get a tire replaced & get an alignment done, on the way there I was on highway, I live in Canada and highway is 100-110 in my province so I was casually doing so. With doing that means the cars RPMS goes above 3000. While driving the cars engine light then came on and went into limp mode causing the whole car to jerk and feel like it’s choking on itself.
so of course before just taking it to shop I went ahead and wanted to see if I can fix it myself, so I connected my scanner to see what the code was throwing and it gave me P2646 A rocker arm actuator system performance or stuck off bank 1. So I started doing research.
everywhere I looked from These forums to YouTube fixes to other sources of forums. They all said to Replace oil pressure switch & spool gasket’s on the variable valve timing solenoid and the other spool gasket, replace the actual Valve timing solenoid, and of course replacing the whole unit itself, or has dirty oil (I did an oil change alread). The “unit” I’m speaking of is this
Ive replaced all above but the code came back, in the time span of all these parts coming in and me getting my actual hands on them I took my car to shop for new alignment and balances for all 4 tires, they ended up telling me It pretty much has something to do with my valve timing? Which I thought maybe it had something to do with the variable valve timing? But anyway I ended up putting all the new parts in (the ones you see above *not exactly those are stock images obv*) and it did NOT fix the p2646 code. Now in the process of me putting the variable valve timing unit itself back on, I lost one of the bolts that go in the back of the heat shield. So I replaced it with bolt same size just not exactly the same bolt, now I have a slight oil leak not enough to lower my dipstick level within a week of driving back n fourth to work and while at work (I work construction). But since I LOST THAT BOLT the p2646 code hasn’t came back and I haven’t gone into limp mode & I’ve been kinda pushing er to try and make it turn on cause I have another shop that’ll look at it.. but it hasn’t came back in passed 3 weeks and I’m just lil confused and dazed. Why hasn’t the code come back? Is the oil leak why it hasn’t came back? Did it get all the “dirty” oil out that it needed? Is that possible? It is getting colder now.. is it just the fact it’s cold even tho the oil gets to proper temp? I know Hondas are know for oil leaks but this one didn’t have any prior to that bolt (which I plan on getting OEM one from Honda) any answers will help, this is my first post on here I hope it can get some answers and maybe help others.
Last edited by Ardent; Dec 1, 2024 at 01:29 PM.
Reason: Added more information
Did you by chance look at the monitors? If most of them are not set you know they had a power loss whether knowingly doing it or not.
3000 RPM is a problem??
Codes may be active until the system passes self test twice.
Did you by chance look at the monitors? If most of them are not set you know they had a power loss whether knowingly doing it or not.
3000 RPM is a problem??
Codes may be active until the system passes self test twice.
sorry can you explain more? Monitors? As in on my scanner? I’ve had shopped checked and I watched them scan all “12 computers” in the car and no codes were stored or anything. 3000rpms is when it goes limp mode and it’s hard to drive on highways with construction work and travelling cause most speeds around me are 110-100 but doing so causes me to go above 3000 rpms which I cant when limp mode happens or it’s just chokes on itself.
If it went into limp mode you will have codes. Something is funny.
I bet we have a tranny codes.
I watch them take my car plug something in the obd2 then they upload it to computer and look at all computers in the car… it scanned all 12 conputers, tranny fluid is fine and has been fine, my scanner and the mechanic scanner says no codes for anything only code I have is low voltage battery which is not even effective I was told just told my alternator can go eventually
NO - Adjust the engine oil to the proper level, then go to step 21.
2. Turn the ignition switch ON (II).
3. Clear the DTC with the HDS.
4. Do the VTEC TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES - 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/PCM. E
NO - Go to step 5.
5. Turn the ignition switch OFF.
6. Disconnect the VTEC oil pressure switch 2P connector.
7. Turn the ignition switch ON (II).
8. Check the VTEC PRES SW in the DATA LIST with the HDS.
Is SWITCH ON indicated?
YES - Go to step 14.
NO - Go to step 9.
9. Turn the ignition switch OFF.
10. Remove the VTEC oil pressure switch (A) and install the special tools as shown, then install the VTEC oil pressure switch to the oil pressure gauge adapter (B).
NOTE: Install the switch in the reverse order of removal with a new O-ring.
11. Turn the ignition switch ON (II).
12. Do the VTEC TEST in the INSPECTION MENU with the HDS.
13. Check the oil pressure.
Does the oil pressure increase to at least 392 kPa (4.0 kgf/sq.cm, 56.9 psi)?
YES - Replace the VTEC oil pressure switch, then go to step 21.
NO - Inspect the VTEC system. If it is OK, replace the VTEC solenoid valve, then go to step 21.
14. Turn the ignition switch OFF.
15. Jump the SCS line with the HDS.
16. Disconnect the VTEC oil pressure switch 2P connector.
17. Disconnect ECM/PCM connector B (24P).
18. Check for continuity between ECM/PCM connector terminal B1 1 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (B11) and the VTEC oil pressure switch, then go to step 19.
NO - Go to step 27.
19. Reconnect the VTEC oil pressure switch 2P connector.
20. Reconnect ECM/PCM connector B (24P).
21. Turn the ignition switch ON (II).
22. Reset the ECM/PCM with the HDS.
23. Do the ECM/PCM idle learn procedure. Programming and Relearning
24. Do the VTEC TEST in the INSPECTION MENU with the HDS.
25. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P2646 is indicated, check for poor connections or loose terminals at the VTEC oil pressure switch, the VTEC solenoid valve, and the ECM/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - Go to step 26.
26. Monitor the OBD STATUS for DTC P2646 in the DTCs MENU with the HDS. Does the screen indicate PASSED?
YES - Troubleshooting is complete.
NO - If the screen indicates FAILED, go to step 1 and recheck. If the screen indicates NOT COMPLETED, go to step 24 and recheck.
27. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
28. Do the VTEC TEST in the INSPECTION MENU with the HDS.
29. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P2646 is indicated, check for poor connections or loose terminals at the VTEC oil pressure switch, the VTEC solenoid valve, and the ECM/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. pro multis · About Operation CHARM
“Legendary” p2646 code. Curious and Confused as can be.
