2008 s60 2.5T …what should the voltage reading be on both leads with the key on? I’m seeing 2.4vdc on both measured from ea harness connector to ground. I suspect that’s low. What do I trouble shoot?

 

It's probably not a bad crank sensor - what are you trying to fix?

 

Hard start and no start condition. New crank sensor, new harness connector to it, new spark plugs (old had very eroded electrode pins), fuel pressure read with scanner at idle 43.x. Originally had P0336 code. No new codes are setting but still no start. Pulled #1 plug and it's wet, grounded it - no spark. Earlier I did this, with the new plugs, and at that time it had great spark and actually started on 4 cylinders. After one session of cranking and no start the cooling fan came on at full speed, Stopped after a min or so. Also sometimes during cranking over, tach needle will jump up and down. Thoughts?

 

Can you pull live data from the Engine temp sensor - fan coming on at the wrong time and wet spark plugs are a clue. Have replaced plenty of cooling temp sensors, some for no code starting problems (usually as a last resort, don't like to guess at what's bad) - but I don't think any of them were the new style square thermostat housing. How are the connections to the temp sensor? (a new sensor comes with the thermostat (and the whole housing too!)

 

yes I should be able to get live eng temp reading, whenever it decides to start again. When I said plugs were wet, I meant with gas.

 

Live data shows appropriate eng temp rise. Also I discovered the eng will start with the crank sensor removed and wiring disconnected. That surprised me. Back to my original question though. Does anyone know what the reference voltage should be on the sensor leads? I can't find it online

 

Are you messing with this part?

If so here's info - I would check resistance and if it's ok - move onto another theory. Engine speed sensors were a common failure on the red block cars. So with that experience all my techs would say they were bad on the 1991+ aluminum block cars when they could not figure out what the real problem was. (bad air mass meters have always been a wrong diagnosis also!) So - I had two of them in stock (since they did not fix the problem, the old ones went back in) and on the shelf for many xx years when I sold 4 years ago. I can say my shop has never seen a bad engine speed sensor on a 1991 + aluminum block car. I'm in the south not subject to corrosion and that may be why. Yes they changed part numbers in the 2000's. So it's possible. Another possibility (if it's really crank position sensor related) is a damaged flywheel/ring gear. Usually caused by a foreign object in the bell housing (usually an errant bolt). Normally that damages the speed sensor itself. Have seen that a few times.

 

thank you for your narrative and the pics. Yes, part #11 is what I'm dealing with. Is that info stating the voltage to ground on EACH lead coming from wherever, going to the crank sensor is 2.5 volts? I'm seeing 2.4 from EACH lead to ground (measured with multi tester and not sine wave instrument), ignition on, engine off. I assume 2.4 is close enough. So......if the crank sensor is good, voltage to it is good and if you read through the thread with what I've already written, where should I go next in determining the root cause of the hard and no start condition.

 

I fully agree with hoonk- the crank sensor is not at all a common failure.

is the starter original? If so, that would be my guess. They can draw high current and that creates interference with the RPM sensor.

 

Hummm........can't I simply check amp draw to the starter during crank over to check that possibility? If yes, what should that reading be?

 

2.5volts - I don't know - never went that direction in a diagnostic procedure.

Next step for a hard start (did it start right up with the engine speed sensor disconnected?) - have to think about that (any recurring codes stored?)

 

No other codes and yes, to my surprise it started with the sensor removed and disconnected. Go figure. Looking forward to you thoughts after you think on it for awhile.