RPM / Tach Problem !!!
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Joined: Apr 2006
Posts: 121
From: Gothenburg, Sweden
Re: RPM / Tach Problem !!!
Thanks for the answers. I did some testing myself the other day, by adjusting the tire pressures. It seems both front and rear axles are involved in some kind of comparison. And I was unable to make the problem go away completely, only occur at higher speeds.
I'm not sure what to do about it. One tire has been replaced on the car, and the new tire has exact same brand and model (size, rating, all spec) as OEM. The tire pressure experiment suggests the new tire is smaller than the others, though. Strange. I'm leaning towards letting the other tires wear out, then replace all four. The problem only occurs at very high speeds.
I also do think the diagnostics is overly sensitive. The difference in circumference between the tires must be less than a fraction of a percent. The shouldn't cause a fault indication and the CVT entering some kind of limp-home program. (There is no fault indication on the display, but it seems the control units senses a fault and records it silently any way.)
I'm not sure what to do about it. One tire has been replaced on the car, and the new tire has exact same brand and model (size, rating, all spec) as OEM. The tire pressure experiment suggests the new tire is smaller than the others, though. Strange. I'm leaning towards letting the other tires wear out, then replace all four. The problem only occurs at very high speeds.
I also do think the diagnostics is overly sensitive. The difference in circumference between the tires must be less than a fraction of a percent. The shouldn't cause a fault indication and the CVT entering some kind of limp-home program. (There is no fault indication on the display, but it seems the control units senses a fault and records it silently any way.)
Enthusiast
Joined: Feb 2006
Posts: 14
Re: RPM / Tach Problem !!!
This is definitely caused by mis-matched tires.
In my case, the only time I've seen it was when driving on an icy road with chains in a snow storm, but I figured traction was bad enough that I couldn't blame the transmission for just picking an RPM and sticking with it, though it was more like 3000 RPM rather than 4500.
In my case, the only time I've seen it was when driving on an icy road with chains in a snow storm, but I figured traction was bad enough that I couldn't blame the transmission for just picking an RPM and sticking with it, though it was more like 3000 RPM rather than 4500.
Enthusiast
Joined: Jun 2009
Posts: 2
Re: RPM / Tach Problem !!!
Sorry if this is a duplicate -- I don't see my last post.
I had the same problem with my 2006 Civic. Although it was no longer under warranty, a dealer did fix it for free. Tell them to look at Honda Service Bulletin 07-041. My problem started after a tire rotation (4 tires bought together -- but 1st time they were rotated). Apparently the computers detected some minor difference in the tires and "guessed" that the vehicle was cornering, so it maintained the engine speed even when I let off the gas. Until it was fixed, I could only stop the problem by slowing down to 20 or 30 MPH or by slapping it into Neutral. (Like someone else indicated, I could not replicate the problem until the engine was warm).
Anyway, they updated the software and it works as well (or better) than ever. I am suspicious that they might have even fixed a problem I had where Cruise Control had been unable to maintain speed on inclines without racing (they applied 3 software fixes in addition to the one above).
Good luck
I had the same problem with my 2006 Civic. Although it was no longer under warranty, a dealer did fix it for free. Tell them to look at Honda Service Bulletin 07-041. My problem started after a tire rotation (4 tires bought together -- but 1st time they were rotated). Apparently the computers detected some minor difference in the tires and "guessed" that the vehicle was cornering, so it maintained the engine speed even when I let off the gas. Until it was fixed, I could only stop the problem by slowing down to 20 or 30 MPH or by slapping it into Neutral. (Like someone else indicated, I could not replicate the problem until the engine was warm).
Anyway, they updated the software and it works as well (or better) than ever. I am suspicious that they might have even fixed a problem I had where Cruise Control had been unable to maintain speed on inclines without racing (they applied 3 software fixes in addition to the one above).
Good luck
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