Code 42

[Previamanvan]

So I've been trying to remedy this problem since I bought this van. I bought it with a flashing O/D light. It reads code 42. I wouldn't really worry about it since the speedometer works but I don't have O/D at all. And I'm getting horrible gas mileage. I tried replacing the speed sensor on the passenger side of the transmission and it didn't fix it. I read a forum about it being an ECM problem. So I picked up a cheap one and put it in and it didn't fix it. My Hispanic mechanic seems to think it's the O/D solenoid which sits with the torque converter. He wants $1600 to fix it. I'm not sold on that nor will I pay that too fix this wonderful van. I know there's got to be a solution that's cheaper and easier than this but I can't find it. Any ideas?

[Previamanvan]

Anybody up to bounce some ideas around with? Really stumped over here.

[tbkilb01]

Code 42 popped up on my 92 and ended up being a worn speed sensor no.1 speedometer GEAR. I replaced it with another and the flashing never came back after canceling out the diagnostic code. (Removing the fuse EFI-15A for 10 seconds). It Never really affected the operation of the transmission..But my speedometer/odometer stopped. Afterwards only odometer works...Ive yet to check wiring. Do you have your shop manual? Did you manual shift through gears?

[zak99b5]

Code 42 indicates an issue with the VSS, it's wiring, or the ECU. You eliminated the VSS and ECU as issues already by replacing them. Have you checked the wiring of the speed signal to the ECU?

[Previamanvan]

Code 42 popped up on my 92 and ended up being a worn speed sensor no.1 speedometer GEAR. I replaced it with another and the flashing never came back after canceling out the diagnostic code. (Removing the fuse EFI-15A for 10 seconds). It Never really affected the operation of the transmission..But my speedometer/odometer stopped. Afterwards only odometer works...Ive yet to check wiring. Do you have your shop manual? Did you manual shift through gears?

Was that the VSS on the passenger or drivers side of the transmission? My speedometer and odometer both work fine actually. Only thing that leads me to suspect the overdrive not working is I can't go over 60 without getting horrendous gas mileage. I did notice the other day though that I'd accidentally hit the OD button and it wouldn't shift around 50 mph or so and when I turned it back on it did. Maybe it's been working all along and this thing just can't do over 60? I do have a shop manual and I've never shifted through gears. I checked wiring what I could see of the connectors underneath. Found a small amount of some corrosion starting but I rubbed the connector clean and still nothing. This thing really stumps me.

[Previamanvan]

Code 42 indicates an issue with the VSS, it's wiring, or the ECU. You eliminated the VSS and ECU as issues already by replacing them. Have you checked the wiring of the speed signal to the ECU?

Well from what I can deduct from a few sources, it looks like the signal makes it fine to the speedometer since it does work but that it doesn't make it to the ECU somehow. Replacing it was the answer so I though. I guess I need to check the wiring from the speedometer to the ECU? I'm an aircraft mechanic so this shouldn't be too hard but it seems weird that wiring that sits inside this thing and not outside could be the culprit. Maybe a bad solder connection?

[zak99b5]

On a B5 Passat (1998) I had a CEL for implausible signal for vehicle speed.

Speedometer worked fine.

VSS in the tranny was replaced. Still same fault code.

Signal went from VSS to cluster (to drive the speedo) to the ECU.

Cruise control also uses the VSS signal, obviously. Somehow, those wires were shorting or founding out, so the ECU never got the signal. I took those wires out of the circuit, and the ECU was happy.

Not it saying this is how it is with your Previa, but these sorts of issues can, and do, occur.