FYI - Engine Light VTEC System Mystery (& 4WD lost)

[Dnick]

FYI a problem I had (temporarily) when driving up to Sierras (300 mi trip) in the summer. It was 110+ degrees, long steady grades, truck was fully loaded (camping gear, etc., NOT overloaded), & constant highway speeds (75-80 MPH). During one of those long (not super steep) grades, the engine light ("malfunction indicator lamp") came on . . . and I noticed the VTM-4 lamp was on also - all other gauges normal. I pulled over to do a cursory check for obvious problems (fluid leaks, etc.) & found nothing wrong. I throttled back & made my way to convenient turn off & called a dealer. They advised if all seemed OK, I should proceed & check at next convenient dealer location. I was dubious, but relented. It was late Friday in the 'boonies', so I couldn't get to an open dealership 'til Monday. Then, they could only do quick diagnostic (no appointment time), and the 'computer' just said "VTEC system" failure.
I made an appointment for several days later (when they said they could take time to troubleshoot . . . this was a small dealership in a small town - the Honda dealer is also a Pontiac Dealer & Toyota Dealer)
Prior to my getting back there, I experienced a troubling hesitation under full throttle at 'shift points', which I thought was the tranny not wanting to shift. This problem went away when I backed off on the throttle (would then shift to next gear). It turns out this was not hesitation shifting, but was like a "governor" throttle effect at certain RPM level (about 4300 if I recall correctly). It was the engine reaching the VTEC 'kick-in' point, but the VTEC system was not working, so engine would just 'bounce' at that RPM until throttle was backed off.
I also, unfortunately, found that my 4WD system was absolutely not working (got stuck off road temporarily & had front wheels spinning with 'dead' rear wheels). It seems the VTM-4 sytem goes out with the VTEC system. (that's why the VTM-4 light came on with the engine light . . . and no, the VTM-4 light was not blinking . . . which would indicate VTM-4 fluid temperature is too high . . . it just came on & stayed on . . . actually it would go off each time I started the car, but would come on within 20 seconds or so . . . and it would go out when I activated the switch . . . but again, only for a few seconds after which it would come back on again)
So I went back to the dealer for my appointment & dropped off the truck. 'Went back in the afternoon to pick it up & they said "all fixed" . . which it was. The problem is, they couldn't tell me what happened. They read the code (VTEC system failure), reset the system (computer, sensors or whatever), and presto: no problem. This bothered me, so when I got back to So. Cal. I took to our local dealer & they checked things out . . clean bill of health. They verified the previous failure codes (from onboard memory or Honda files or something) & agreed that the symptoms matched the "VTEC system" failure mode . . . but couldn't tell me what triggered it. I'm guessing possibly a fluid temperature threshold or something like that????
Is anybody in this forum techno-smart enough to know what would trigger that kind of a diagnostic code failure??
Anyway, I have to say that even as a long standing Honda freak, I was concerned that with only about 900 miles on the truck, I was annoyed that I would have that kind of a problem. I can say now, that it has not recurred, and they did only have to reset the system. The mechanics speculated that "anything" could have caused it . . . temporary dirt blocking a sensor or ??? I didn't buy it, but I've gotten over it.
So, I'm putting this out there in case any of you fellow members witness the same, you might not need to panic. . . could be the system just needs to be reset. Sounds like it should be a very infrequently occuring problem, but "heads up".

BTW, 4WD worked fine once system was reset. The only thing I was cautious of, on some very precarious mountain trails, was ground clearance (had to be careful there on some very rutted, high center trails). I must say that when I did get onto some of the better off road trails, this Ridgeline is the best vehicle I have ever ridden over bad washboard roads.
But I went everywhere I wanted to except for high center trails or until we hit the high snow line (this is where the snow was still half way up the pine trees & there was no passage even if you had a real rock crawler). We had fun despite to problems - its just a good thing I had two weeks to spend up there!

[bonerep]

Too bad about the VTEC failure. The rest of the trip sounds great. I'm heading to the mountains for Thanksgiving and I am looking forward to it. What dealer do you use @ home?

[Dnick]

Originally Posted by bonerep

Too bad about the VTEC failure. The rest of the trip sounds great. I'm heading to the mountains for Thanksgiving and I am looking forward to it. What dealer do you use @ home?

Hoehn in Carlsbad. Nothin' but great service so far.

[Lingered_I]

You might want to check your oil level. The VTEC system is controlled by an oil pressure switch and a solenoid valve. If the oil level is ok and you still have an intermittent problem, check the electrical connections. Standing at the front of the truck looking into the engine bay, the components are on the left hand side mounted to the same assembly that the oil filter screws into. The oil pressure connector is mounted directly to the switch, while the solenoid valve connector is in the cable coming off the valve. To check the valve, disconnect the connector and measure the resistance between the single pin and the body ground. You should get between 14 and 30 ohms. Anything else and it's likely faulty.