I installed the AVIC-Z1 and it has been working fine for 2 months. I wired it into my ECU's speed signal wire and that has always been reporting the correct speed under the vechile diagnostics and allowing the GPS to guide properly.

Two days ago my GPS stopped working and my car began sputtering and stalling. I determined that it was a problem with the ECU and disconnected the headunit's speed sensor lead. The car ran fine again when i did this.

When the speed signal sensor wire is hooked up it reads 0.0mph most of the time, except when i'm accellerating or revving my engine, then it reads 0.7mph-4.7mph.

I checked all the connecting and replaced the entire wire that was used for the signal and get the same results. I can only assume that the headunit itself is back feeding a signal into my ECU.

Anybody else seen this or anything like it?

Since you're head unit worked fine, I'd have to think that your ECU is sending a bad signal to the AVIC. Go to the diagnostics screen of your AVIC and see if the pulses are even. Pretty unscientific, but it may be a start to find out if it's receiving consistant pulses from the ECU.

ImolaVirus said:

Since you're head unit worked fine, I'd have to think that your ECU is sending a bad signal to the AVIC. Go to the diagnostics screen of your AVIC and see if the pulses are even. Pretty unscientific, but it may be a start to find out if it's receiving consistant pulses from the ECU.

I would disagree with that. Since disconnecting the VSS wire from the Z1 fixed your car's drivability issues, I would say the problem is in the Z1. This would be a good problem to bring to Pioneer's installer help line.

Try placing an appropriate diode in line. The Z1 should not be sending anything down the VSS wire but if it is, this will prevent it and you will still recieve the signal from the ECU.

You've attached the Z1's VSS wire to the vehicles TACH wire. Post your vehicle make, year and model and I'll tell you which wire to attach to.

I just re-read your post and see that you had it working at one point. Are you 100% positive you hooked the vss wire back to the apropriate wire?

hey edrock.... i have a 2001 vw jetta glx, manual, 5spd, black. can u tell me which to hook the wire up too thanks!

Anonymous said:

hey edrock.... i have a 2001 vw jetta glx, manual, 5spd, black. can u tell me which to hook the wire up too thanks!

This is a difficult wire to find. I didn't find any solid evidence, the best I found is:

"on the blue plug to the cluster either oin 26 or 28" no color specified though one person said *maybe* green.

That said, the info above is by no means concrete, I would confirm with someone or meter it. Metering it will be difficult however since the car needs to be moving for the vss pulses to occur.

Speed Sense WHITE/BLUE (AC) DRIV FIREWALL 3 WIRE PLUG FROM TRANSAXLE
Possibly also located at cluster pin 3
Keith