1998 S70 Fixed Transmission Range Switch... Now Trans Fault

[Ozark Lee]

I don't believe in coincidences. If the car ran fine before the PNP was disassembled to fix the reverse lights but now the transmission is in limp mode immediately after that then the problem has to be somewhere in the PNP switch itself or in its cabling. You can use an ohmmeter at the connector end to check for continuity in the various gears selected to find the problem.

I cannot post schematics for you (someone else can but not me) but the switch is the same as an 850 and you can glean information from the 850 factory service manual. There is a truth table and the wire colors in a couple of places in it.

https://www.matthewsvolvosite.com/downlo ... vo_850.zip

...Lee

[ferocity02]

UPDATE: After sitting overnight the transmission fault is gone, and the trans shifts normally now. BUT, the CHECK ENGINE light is still on. It comes on a couple seconds after starting the car. When I scan for codes nothing comes up. When I clear codes the light doesn't turn off. So I pulled the battery cable and will let it sit today and see if that clears it.

I'm thinking that powering on the car while working on the range switch caused a fault that took a drive cycle to clear.

[cn90]

From your other reply (in the other thread), it seems that the culprit was the copper contact that was worn in an angled manner.

I last did this 3 years ago. See the post from 23 Dec 2012:

https://www.matthewsvolvosite.com/forums ... 1&start=42

The bottom line is:
- Mount the copper contact on a vise-grip and file it nice and square.
- The OUTERMOST copper contact had the most wear, so I swapped position with the INNERMOST position (which has the least wear and tear). Remember that this is all common sense, look at the "railroad tracks", the one farthest from the center has to go through more distance.

Three (3) years later, things work just fine.

[ferocity02]

UPDATE:

The CEL was caused by a trans fault for a low signal from the gear selector switch. This is probably because I turned on the ignition with the PNP switch unhooked. Oops! The ECU also had code EFI-666 which indicates the presence of a trans fault which causes a CEL. I cleared both the trans code and the ECU code and so far so good. I used Vol-FCR to do this.