1998 S70 Check Engine Light but No Code

ferocity02 · Post by **ferocity02** » 27 Oct 2015, 12:15

Yes another problem thread with my 98 S70 GLT... a couple days ago I took apart the PNP/Range switch to fix no reverse lights. All I did was clean it out and smooth out the contacts, along with some new dielectric grease. While the switch was taken apart (along with the MAF sensor unplugged and some vacuum solenoid thing attached to the rear of the airbox unplugged) I turned on the ignition (engine off) to verify the PNP switch was working and reverse lights came on. During this process a trans fault was present I figured because the PNP switch did not match the gear selector.

I put it all back together and still had a transmission fault (flashing up arrow) and a check engine light. After sitting overnight the trans fault was gone but the check engine light was still present. I pulled the battery for about 4 hours and it didn't clear it.

When I scan for codes nothing shows up. When I clear codes it does not go away. The emissions readiness tests are not completing either (I know they are notoriously difficult to complete on this car but at least the easy ones should go).

The check engine light is on with ignition on engine off, then turns off once the engine starts, then turns back on about 5 seconds after starting and stays on.

Am I correct in assuming this is something the dealer needs to scan for? I need to smog in about 3 months and a Check Engine light is an instant fail.

Post by **regent** » 27 Oct 2015, 15:05

Do you have access to VIDA/DiCE; if not - an indie that has it may read the code(s) for less $$ than what the stealership charges (110 bucks in CA I believe)

Apart of reading codes, if I am reading correctly, you used 'Some New Dielectric Grease' on the contacts??? 'Dielectric' is exactly the opposite of 'conductive' and I'm afraid this could be the source of your intermittent poor contact. There are contact cleaners and contact lubricants that leave a non-corrosive conductive film on the contact surfaces. I would double-check that New Dielectric Grease and clean the contacts afresh if necessary, and then apply the correct stuff.

ferocity02 · Post by **ferocity02** » 27 Oct 2015, 15:26

regent wrote:Do you have access to VIDA/DiCE; if not - an indie that has it may read the code(s) for less $$ than what the stealership charges (110 bucks in CA I believe)

Apart of reading codes, if I am reading correctly, you used 'Some New Dielectric Grease' on the contacts??? 'Dielectric' is exactly the opposite of 'conductive' and I'm afraid this could be the source of your intermittent poor contact. There are contact cleaners and contact lubricants that leave a non-corrosive conductive film on the contact surfaces. I would double-check that New Dielectric Grease and clean the contacts afresh if necessary, and then apply the correct stuff.

I do not have VIDA/DiCE.

I used dielectric grease because I did not want to use anything conductive or else the grease would conduct across rails that should not be touching, causing shorts... if that makes sense. As far as I know the PNP switch is working fine now (unless the mystery check engine light is related to it). The couple of DIY's I found say to use dielectric grease. The conductors are spring loaded so their contact with the rails shouldn't be inhibited by the grease.

ferocity02 · Post by **ferocity02** » 27 Oct 2015, 16:04

I found a table with PNP switch specs in a document that someone posted in one of my other threads. It's for a 95 850 but hopefully applies to my 98 S70. Seems pretty easy to measure with a multimeter at the TCM connector. I'll give it a shot.

Post by **erikv11** » 27 Oct 2015, 21:28

Grasping at straws here but one very common source of transmission codes (which many scanners do not read) when it seems that nothing is wrong, is the TPS. It can set a transmission code and flash the up arrow, one or the other or both. Did the TPS connector maybe get dislodged while you were working in the area there near the PNP? Do you have a spare that you can swap in?

ferocity02 · Post by **ferocity02** » 30 Oct 2015, 12:08

erikv11 wrote:Grasping at straws here but one very common source of transmission codes (which many scanners do not read) when it seems that nothing is wrong, is the TPS. It can set a transmission code and flash the up arrow, one or the other or both. Did the TPS connector maybe get dislodged while you were working in the area there near the PNP? Do you have a spare that you can swap in?

TPS is plugged in. Car behaves perfectly normal except for the Check Engine light.

Turns out I cannot test the PNP switch at the TCM connector because the TCM needs to be plugged in for the truth table to work. You need a special tool to do it which costs like 500 euro... What I'll have to do is remove the PNP switch and check for continuity across its connector pins in the various gears using a wiring diagram. And then test the continuity of the wiring from the TCM connector to the PNP switch connector.

Local dealer wants 1 hour @ $125/hr to read the code... ridiculous.

Is there VIDA/DICE out there that will work on a 1998? Most seem to be 1999+

Post by **erikv11** » 30 Oct 2015, 15:15

There are lots of commercial code readers that can grab transmission codes, or the inexpensive route is to go with VOL-FCR.

ferocity02 · Post by **ferocity02** » 30 Oct 2015, 15:26

erikv11 wrote:There are lots of commercial code readers that can grab transmission codes, or the inexpensive route is to go with VOL-FCR.

VOL-FCR seems to be more expensive than VIDA/DICE, but it seems that it can handle a 1998 model. Are there any other tools/software like this that could handle a 1998?

What commercial code readers will work?

I am using the Torque app on my Android and it works well but seems to only handle basic OBDII codes.

Post by **erikv11** » 30 Oct 2015, 16:29

Tons of info in this forum (and others!) about how to get VOL-FCR for very cheap (OK very cheap if you already have a PC laptop), do some digging if you need to but at a glance this link seems to cover it pretty well: https://www.matthewsvolvosite.com/forums ... =1&t=68710

ferocity02 · Post by **ferocity02** » 31 Oct 2015, 19:22

Thanks for the link. I'll have to see if I can get the cable and software.

I was able to do some continuity checks on the PNP switch and it appears to be in 100% working order in all gears.