Hello - New to the forum but been working with cars for a while now.


Purchased a super cheap, non-running (no crank) 99 S80. The rust free body was too much to resist in Minnesota.


I have read the below posts and a large number of others on here and other outlets online. I am stumped. I will run down where I am so far.


Battery - DOA - replaced with new, no change
Starter - Jumped the Solenoid - engine turns over without issue
Starter Relay - supplied power/ground and clicks and makes connection
Ignition Switch - voltage checks out in position I, II, & III


Antenna Ring on column - Unsure how to test
Park/Neutral Switch - Unsure how to test
Immobilizer - No messages on dash, but not sure how to test beyond that


Wiring at Relay -
1/86 - 12v when key in position III (Good)
3/30 - Constant 12v (Good)
5/87 - Has continuity to starter solenoid (Good)


2/85 - Key Pos III (should be ground supplied by ECM)
Will show 12v on multimeter when used as ground
will NOT light up incandescent test light when used for ground

 

85 is grounded by the CEM, not ECM.

So when connecting a volt meter between 30 and 85 with the relay removed, you have battery voltage when the key is in position 3?

 

I was checking the voltage on 30 via a body ground. It should ground through the starter when the relay is activated, correct?

I tested 85 with the 12v feed on the firewall. I could use the 12v constant at 30, would that matter?

 

Correct, the circuit grounds through the starter when the relay is closed.

And you can use any 12v source for checking 85. I'm just trying to confirm you used 12v. So with the relay removed and the meter on 12v and the terminal where 85 would go, the meter reads 12v when the key is in position 3?

 

Correct, in position 3, showing 12v on meter when using the 12v lugs at the DS firewall and using 85 as my ground.

It does not light up my test light though when using the same 12v source and 85 as ground.

Edit:
Jumped the 85 to ground and can get a crank (no start) with key in position III.
All fuses check good

So I guess the question is what modules, sensors, checks does the CEM require before supplying ground?

 

If the CEM isn't grounding the relay, you're going to need VIDA and a DiCE to check codes and make sure the network is good. But if you have 12v when going between the power and terminal when in position 3, the CEM is grounding it.

 

That is the oddest thing. I can read 12v but it won't light a test light.

I can also get it to crank if I supply a ground to the relay post via jumping it to a body ground, so the ground is the missing component to the situation.

Downloaded VIDA, gotta figure out the most affordable solution for hardware.

Is there component that often fails? I could swap 5-10 used parts before paying for diagnostic hardware.

 

It's a 99 S80. Diagnostic equipment will certainly be used plenty if you keep that car. CEMs fail on those and a replacement would probably exceed the value of the car. You can't swap a used one. Could be why you got it so cheap. Same with TCMs.

 

Is it worth keeping it then? I suppose I don't know for sure that is the issue.

 

Hard to say without knowing what the problem is. Why was the car so cheap? Probably because its expensive to fix.

If someone gave me a 99 S80 for free, I would probably siphon the gas and scrap the rest. And I get a nice parts discount, access to VIDA and my labor is free.

 

Parting it out had crossed my mind. Its all in good shape

Just ordered a knockoff Dice. Im curious to know if i can fix it.