Hi guys. My 97 DX Coupe threw a CEL for the VSS. I replaced the VSS, but no change. I've probed it with a multimeter, but I don't really know what I'm doing. Im only getting 5.5v on the harness side to the blue & black wire. I think the book indicated it should be battery voltage (currently 14v). Then it has me checking continuity, harness side. I can't seem to get any kind of steady change in the multimeter running the harness to ground. The best I can manage is a momentary flash of about 150ohms before it goes back to infinity. I skipped part three which is checking the VSS, since I already replaced it. I did however perform an idiot check: The pin that runs off the diff and spins the magnetic rotor in the VSS does turn when the wheel turns. If it matters, I have a 92-95 transmission in my car. VSS did work before the trans swap.

I'm an electrical dimwit. Would someone point me in the right direction? Is there a way to hotwire or ghetto rig this thing back to life? And what fuse circuit is the VSS on?

 

Fuse 15. Since you have a 1997, look up the fuse 15 problem. Basically the wires on the back of the engine short out where they come across to the alternator and VSS. The 3 wires to the VSS are 12 volts with the key on, ground, and the output which pulses between 12 and ground as the wheels turn.

 

Fuse 15 is not blown. Still not fixed. I'm kinda at a loss... my car's off the road b/c of this stupid ****. I don't even care if the speedo works, but the CEL is keeping me from passing inspection.

 

You have a 1997 you have to check for physical damage to the harness behind the engine where it goes across the intake manifold brace. This is a known problem that started with the 1996 model.

 

suppose to only get 5v, not 5.5v

 

The VSS runs directly on ignition switched 12 volts from the fuse 15 circuit.

 

CEL for the VSS? Does the VSS go through the ECU in OBD2 cars? When I diagnosed my broken speedometer on my 92, it was strictly between the cluster and the sensor.

Anyways, is your speedometer not working? Did you pull your cluster and check the solder joints on the back of the cluster? https://honda-tech.com/forums/honda-.../#post51227153 (keep in mind that's for an OBD1 car so it may be different)

 

Ghetto rigging ftw! Lol

You could just run a +12v supply wire from your under hood fuse box (should be able to tap into one of the extra slots with a male spade terminal), get one of those little fuse holders to hold a properly rated fuse, run a new ground wire, and run a wire to the back of your gauge using a small ring terminal under the head of the screw that supplies the VSS signal to the speedometer; all of these wires would need to be spliced into the connector for the sensor.

 

 

Wont that still throw the CEL code? I mean, it wont if the 12v supply is the problem, but if the problem is on the signal wire, the ECU still needs to see that right?

 

Yes it would still throw CEL code. The ECU needs to see a signal from the VSS.

Test with an ohm meter with the car battery disconnected. The yellow and black wire should have continuity to the yellow and black wires on other fuse 15 systems: the alternator, the purge solenoid, the oxygen sensors. The black wire should have continuity to ground. These wires have splices inside the engine harness. You may need to remove the engine harness from the car, unwrap the tape and fix the splices. But fix it right, don't try to rig stuff.

 

If you do it like I'm saying, it may actually feed back through the cluster to the ECU. I'd have to check the wiring diagram.

 

You get the MIL code because the ECU doesn't get a VSS value greater than 0 mph. The code is set once the car is traveling at a speed greater than 45 mph and then slows below that speed. So, if you repair the VSS signal to the ECU, you should be fine to pass inspection. I don't think the speedometer needle sitting at zero will be a problem... and I am fairly confident that it will not set off a code.

 

Update: Pulled multimeter back out idk what I was doing wrong before but here I have:

1.9ohms between sensor ground and battery negative. I'd like to see this less than 1, but it's acceptable I guess...
5.5v supply voltage with 14v across the battery, car running (should be at least 12v)
4.85v supply voltage with 12.5v across the battery, car not running (Should be at least 12v)

I think this indicates a leaky supply voltage. Under the car now looking for damage behind the intake... wish me luck.

 

Well, eveything looks pretty good. I'm kinda suspicious that it's sitting at 5v. That's a really common voltage for electronics to run off of.
It would be really helpful if someone could check their own voltage. My manual is for '92-'95 and indicates 12v. The speed sensor is also a fifth gen and would require 12v. However, if in the 6th gen (my car), they changed it to run on 5v, then I'm supplying the correct voltage, I dont have wiring problem and this sensor is just never going run without a few extra pixies.

TLDR: IF YOU HAVE A '96-00 Civic please test supply voltage to your speed sensor for me!

 

It is a 12v circuit. Check continuity between the black/yellow voltage supply wire at the VSS plug to the junction plug under the intake manifold. Closely inspect the wire visually for any damaged strands or cracked insulation. If all looks good, check the voltage on adjacent wires in the junction plug as well as the feed wire for it. Remember that all of the wires at this junction should be the same color. If not, maybe it is incorrectly installed in the wrong location. Also, the only 5v circuits in a '96-00 Civic are the MAP, TPS, ECT and IAT... all other circuits will be 12v.

 

 

Guys, I finally have it repaired! It turns out the spade for the 12v supply snapped off. So it looked like there was a spade there, but a tiny bit of it was missing! So dumb! But I spliced on a new connector and now it works again. Thanks for the input!