Civic electrical problem

SLOW_DEATH_HONDA

MEMBER
HONDA CIVIC

1997 Honda Civic DX 207,000+ miles.

This issue started as a jumping speedometer that eventually blew a fuse. After two fuse changes, the speedo eventually stopped working without blowing anymore fuses. Shortly thereafter, the car will occasionaly stall when cold and stopping at a light and the idle seems to drop below the normal level.

The only error code generated is code 17 (speed sensor circuit malfunction).

I recently replaced the speed sensor with no change to the issue. I have ordered and am going to change the speedometer as soon as it arrives suspecting a bad cluster.

But this morning, a new issue popped up I believe is related. When I step on the brake or activate the turn signal, the radio loses power momentarily. I believe the taillights might be lighting after a short delay when pushing the pedal.

Could this be an alternator or generator problem? A short in the harness that is getting worse? Grounding problem?

Any help is appreciated.

4 Replies

BRUCE HUNT

MECHANIC
3,753 POSTS

You took the avenue I was heading down. I suspect the alternator. I would run the engine and check the voltage output at the battery. It should be in the 14 volt range.

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Monday, October 1st, 2007 AT 11:47 AM

SLOW_DEATH_HONDA

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Thanks for the response, Bruce. I negelected to include that I checked the alternator. 14+ volts at idle, 14+ with every accessory I could turn on at the same time: wipers, defrost, AC full blast, radio, turn signals, high beams.

I would think that could be considered a passed test.?

As an update, I have a battery cut off switch installed to quickly reset error codes. I mucked around with the switch and ground connections to the body and the intermittent radio problem seems to be gone for the moment. (I made the mistake of not starting the car after sitting for a few hours before messing around under the hood so I am not sure if I had a hand in repairing it or if it would have magically been gone on its own.)

I got the used speedo last night and put it in and no change.

Maybe the speedo and this problem are related to a short in the harness under the engine? I have read where some have found shorts from chaffing under there. I will be crawling under soon.

Since I have now replaced every component (I think) in the chain except for the wiring, that's got to be it, right? :Evil:

Oh yeah, I also replaced the ECU with a used unit as well as these have been known to be bad on this model year.

Anybody have any other suggestions?

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Tuesday, October 2nd, 2007 AT 8:57 AM

BRUCE HUNT

MECHANIC
3,753 POSTS

Wow, no not really. You seem to have it covered.

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Tuesday, October 2nd, 2007 AT 2:36 PM

SLOW_DEATH_HONDA

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3 POSTS

In case anyone with a similar problem finds this thread, here is what the solution was. This solution would have been much harder to find without the service manual for this car found on the internet.

There was a short in the wiring somewhere between the fuse box and the VSS (Vehicle Speed Sensor) so that the positive power lead was not supplying voltage. (For this car it was specifically between connectors C101 and the VSS, there is 1 connector between those, C115, but it is in the middle of the engine above the block but under the carb. Nearly impossible to get to without dismantling the carb.)

What I did was verified power in connector C101 then ran a jumper wire from there to the wire just at the VSS connector bypassing the failing circuit.

This restored power to the VSS and allowed for the speedometer to function and the error code to clear.

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Monday, October 8th, 2007 AT 8:28 AM