Wow; monkeys must have worked on this car before me. The two wires at the VSS plug were shorted together, apparently intentionally. Some bizarre test? Straightened that out, tested continuity from each of those wires to the PCM wiring plug, good, but CEL still on.

VSS may just be shorted, but then again it could have shorted out the PCM. I should have my Mitchell book tomorrow; I will test the VSS for shorts, and also the pins at the PCM, and the TCC solenoid if necessary. We'll see,

SideSaladMeal

If they were shorted together from the start, you would have had issues from the start. Not 5 miles down the road.

Well, lots happening. Fixing the plug at the VSS seems to have corrected the tranny weirdness. Tech guru tried scanning again and couldn't; but what got his attention was when I told him when backprobing the PCM, I get 4.5V at the knock sensor pin; Mitchell says it should be 1.2...he said THAT'* the kind of disconnect we are looking for. Today I bolted on a front sensor from a '95-prior, with the correct connector, and got 2.43; light still on. Left the rear disconnected; wiring diagram seems to show 2-into-1 wire, which I assume means EITHER front or rear out of range triggers something in the PCM. Do they both have to be hooked up? Can I hook the two wires together? That rear one looks impossible to swap with engine in car. Mitchell says 2.5V is the most you can even get on the '95.

Went to just check to see what hex size the O2 sensor is, and it was LOOSE. Unscrewed it all the way out by hand. It didn't look horrible but who knows...after I tightened it, my O2 voltage at the PCM went to totally normal, even in what I assume is 'open loop'. Before this, it was way high. Oh; Friday I found the #5 plug mashed so that it had almost no gap.

After all of this, my CEL is still on. So I'm ready to finally buy the Actron but this voltage discrepancy on the knock sensor still bugs me. --

Meal4Niners?

I'll just stand here in the corner patiently tapping my foot waiting for the Easter Bunny, Santa or somebody to bring you a scanner.

As far as the knock sensors, I think they are individually pinned at the PCM. Otherwise, how would the PCM know which bank is knocking?

Your wise counsel has borne fruit...just won an eBay best offer for the scanner, with cables. Should be here in a few days.

Continued to play around though, of course. Yesterday I tried to remove knock sensors from THREE '95 Bonnies. So here'* the thing...when they've been on there for like 19 years, and were installed with thread sealer, THEY AIN'T COMING OFF...the hex section busts loose from the rest of the unit and spins. At $33/ea new, I'll let the Actron gods tell me they're bad. Did score the correct oil level sensor plug and installed that.

Today continued to test for voltage at the PCM and everything checks out except WD13, service engine soon light, gets .21V instead of 12V with engine running. I hotwired it and it didn't make the light go out. Bizarre. Oh, and I assume with KOEO I should have a light on for that? I don't. Other one is WD3, A/C refrigerant pressure switch, measuring negative voltage. This thing controls the fans somehow. Checked for short and open, nothing doing. So nowhere to go on those two unless somebody has some insights.

AllIWantforDinnerisActronMeal

Guess I'm a real Bonnie ADDICT (do they have 12 steps for this?), but hey, does anybody know how the MIL circuit function works on the '95? I'm looking at the wiring diagram and the gauge/light gets 12V from the fusebox, but the other side of the light is the one that goes to the PCM at pin WD13 and Mitchell calls that 'malfunction indicator control' so that comes FROM the PCM TO the light, yes? To light it up when there is a problem or a mileage milestone occurs maybe? Mitchell says that pin should have battery voltage with engine running and I don't have that. Also, I assume you normally get 'service engine soon' light when with KOEO? If the bulb is burned, does that mess up the whole circuit? Thanks for all of the help,

MealMeal

the pcm provides a ground to turn on the light. since your light is on it would show 0v. if the bulb is burned out it detects that and will give you a code for it when you hook it up to the scanner. key on you should get 12v from the source to the plug if you take it loose from the pcm. if you do your bulb and that circuit is good

Thanks, Justin. I need to take a step back; are you saying the MIL and the 'check engine light' are one and the same? I thought the MIL and the 'service engine soon' are the same thing, but separate from the check engine light. Am I wrong there? I have the check engine light on. I do not have any SES light even with KOEO. Is there a separate SES light on the '95 Bonneville? Thanks man,

Mealticket

mil,ses,and check engine are all the same thing.usually if referring to the MIL though they are referring to the light itself. and ses or cel would be referencing the code set when the light is on. for future reference the only other different light would be if you got a abs or traction control fault

Received my CP9145, ran it, got 1 code: P0325...KNOCK SENSOR! If I had been able to get the sensors from the wrecks the other day, I likely would not have had to buy the scanner...I got a detailed procedure for the code from my guru but it clearly shows anything over 2V throws the code, so I really don't need to do any more diagnostics. I already know the voltage is over 2. Just need the sensor(*). Stay tuned,

MealSoon