2001 SL2 just died :(
 

First off...Hi my name is Brian. I'm obviously new to the boards and I could use some help. Thankfully google brought me here to you guys :)

I drive a completely stock 2001 Saturn SL2. I went out for a drive the other day and got about 200 yards before my engine just died randomly. I took the car to a local auto shop and they believe the ECU is bad. There is no spark and no communication with their scan tool.

What I'm not sure about is how the car can turn over if the ECU is bad. I was thinking that the timing chain might have possibly skipped and now my timing is off causing the car to not start, but I've been told the timing chain should be good for a couple hundred thousand miles at least. Just wondering if anybody has had this issue before or you give me your insight on the problem. Thanks in advance!
-Brian

Sudden death while driving + no spark afterward usually indicates the crankshaft position sensor (CPS) has failed.

Resistance across the CPS should be between 700-900 Ohms.

Even if it is seemingly in spec, if the signal it is sending to the PCM is distorted, it will inhibit spark (by design), as the PCM will not allow spark at the cylinders since it does not know where the crank is in its rotation.
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Are you getting fuel to the cylinders?
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As for the lack of communication through the ALDL --- check the fuse and the wiring.
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PCM failure is not overly common on the S cars.

If your timing chain jumped you likely would hear the crunching of your valves -- or the aftermath of said event -- as these are interference engines.

^Thanks a lot for the insight. I've been reading a lot about the issue and it does sound like the CPS could be the problem (lets hope it is). I'm going to replace this right away.

A couple quick questions...
PCM: ?
ALDL: ?

Thanks,
-Brian

PCM = Powertrain Control Module == ECU

ALDL= Assembly Line Diagnostic Link == the connector where you hook up the scan tool under the dash

Didn't mean to be cryptic (forgot you were a noob)

^hey watch it bucco haha. I'm a newb to saturns. When it comes to dsms and subarus I'm a step ahead of ya ;) ECU's and OBD II's are more my lingo haha.

Update:

I just spoke with the shop and I asked what he thought about replacing the CPS. I also questioned a little more about how their scantool worked. Since the car wont start, and when the keys are in accessory, all the lights (including the CEL) are on. He informed me that when they tried to scan the car there was no response from the ecu. If the CPS was out, wouldn't that throw a code that the scantool would in return read? He went on to say that along with no spark, there was also to pulse to the injectors. Obviously, no spark + no fuel = no good.

If in fact it is the ecu, is that something I can put in myself? I was told that the dealership would have to reflash the ecu, is this true?

Thanks again,
-Brian

Brian,

The reason I asked if you had fuel at the injectors is because whent the CPS goes on these cars, once the PCM fails to get a signal from the CPS, it often blocks the pulse to the injectors since it doesn't want anything to fire without knowing where the crank is in its rotation.

You need at least a partially functional PCM for that decision to be made.....

One could of course argue that there is no fuel b/c the PCM is dead and not sending the pulse....but then how do all those dash lights come on when you turn the key? (That's part of a diag loop and you need at least a partially functional PCM for that too.....)

And do they all stay on, or do they come on and all turn off except oil, battery/charge, and maybe MIL (CEL)?

Dead CPS does not always set a code....
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They'll also find that they are much more likely to get a response from the PCM to the scan tool f they they turn the key to "ON", not "ACC" -- they should know this.....
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Get the impression they don't work on many Saturns.....
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Go buy a CPS from a Saturn dealership, take it to them, watch them put it in (takes 2 minutes with car on a lift). I suspect you'll be on your way down the road....

its a hell of a lot cheaper than getting a new PCM.....

Update: I stopped by the stealership yesterday and they charged me $50 for a new cps. I know I could have found a cheaper one online, but I'm in a little bit of a time crunch.

I brought the new cps to the shop where my car has been for the past few days. I had them install it for another $50 labor. I figured $100 is a lot cheaper than $1100 so I didn't really care. Well, the guy installed the new cps and still nothing. The car wont start... http://www.saturnfans.com/forums/ima.../new/frown.gif fail...

dang. thought this one was pretty cut and dry.

Are they getting an injector pulse now?

As far as I know there is no pulse. :(