02 Saturn SC2. Cranks, no start. - Saturn Forum - Saturn Enthusiasts Forums


Saturn 3 Door Coupes SC1 and SC2

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Old 01-25-2018, 09:59 PM
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Default 02 Saturn SC2. Cranks, no start.

Iím helping a friend fix his car. The battery kept draining overnight and wouldnít be able to start in the morning. So it sat for a few months.

I managed to chase down the electrical drain (both power door lock switches). But after we sorted that out now it wonít start.

Iíve found out that the fuel pump relay is not getting the 12v trigger signal to turn the pump on.

But it even if I bypass the fuel pump relay, and let it pump non stop I still canít get the car to start.

Now im trying to read codes, and the code scanner just gives an error. The diagnostic port does have 12v power though.

Iím thinking maybe the PCM is bad? Iíd like to know for sure before buying a replacement one though.

Anyone have a clue?
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Old 01-26-2018, 12:00 AM
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I've found out that 3 of the wires going to the diagnostic port are ground. Two of them are supposed to be, but pin 2 the purple wire I believe is not supposed to be and it shorted somewhere between the diagnostic port and the BCM.

Going to dig into it a bit and see what I can find.
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Old 01-26-2018, 02:37 AM
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Looks like the Body Control Module is shorting out the diagnostic communications circuit.

Are those common failures? I dont think that would cause the car to not run though.
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Old 01-27-2018, 10:28 AM
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Were the power door locks stuck in the LOCL or UNLOCK position, causing a constant drain? Or were they functioning properly other than the current drain? Seems they would have had to be if it was the actual switches as I don't believe they are powered by any other path and therefore can't drain to ground any other way without popping the fuse.
I have seen posts where the BCM commands the relays to close but never to reopen, so it's the equivalent of holding it in the "UNLOCK" position the entire night.

Did you change the battery or have it tested at Autozone or similar for free? The repeated overnight drains, combined with the 2 months of sitting, likely has killed its ability to hold a charge. and equally possibly not provide enough current to the car's electronics during startup. The BCMs and ECMs in these cars are finicky about sufficient V and current levels, so if the initial part of the startup sequence is not operating as designed, you really don't know what's working and what's not.

Troubleshooting this requires a good battery to begin with. Working off a jumper hook up battery will not cut it.

The 12V signal to close the fuel pump relay to prime on startup and stay closed during operation receives its current and Voltage from the IP BATT feed from the battery, to pin F2 on the Instrument Panel Junction Box (either F2 or F5; I've never owned a 3rd gen S car, they are diff for each gen.).
Do the dome light and chime work? Sounds totally unrelated, but these circuits are traditionally fed off the F2 pin along with the fuel pump.

You indicated that bypassing the fuel pump relay turns on the pump. But have you checked that it is generating fuel pressure at the rail? Under the hood, there is a Schrader type valve on the fuel rail leading to the injectors. After cranking 2 or 3 times, put a rag over it and depress the center pin. A healthy spray of fuel should come out so keep your face away from it. A fuel pressure gauge is even better.

All that being said, I BELIEVE the fuel pump relay is controlled by the BCM on third gen S cars (only ones that had a BCM).

What is the status of the security light when the car is just sitting there and when you are cranking. The security system may be triggered. [EDIT] This kills the fuel injectors. It does not kill spark nor inhibit the fuel pump[EDIT],

The security system module is embedded in the --you guessed it -- BCM.. It is entirely possible that the PASSLOCK password has gotten fubar''d during all the drain cycles. There is a PASSLOCK relearn procedure which is all over Saturn Web sites including this one, so you can track that down and try that. THere's a quick version and a long version. Just go straight to the 30 min version and follow the directions TO THE LETTER or it will not behave as intended. You may need to perform it multiple times for it to be successful. ****Jumper your battery to a running vehicle during the process, as it will otherwise drain your battery significantly that the procedure will fail.

Your findings with the diag bort are not promising but may be a side effect of the secuity system, though I don't know why a thief would want to pull codes on a stolen vehicle. Sounds again like BCM .

Your issues could also be related simply to bad gas.

I tend to write my replies train of thought, with the simplest explanations not at the beginning. I get razzed all the time for doomsday troubleshooting, but if I don't type it when it comes through my mind, it's gone.


------------
So I'd start by
--checking for spark when cranking
--bad fuel
--perform passlock relearn with running vehicle jumped

This may all be in vain but I will not condemn the BCM until all other options have been exhausted, as it is not cheap to replace , even with a junkyard unit, and it has to be flashed by someone with a tech Ii device AND the firmware to download ====the dealer.
. If the current drain was from the door lock switches being constantly commanded on, that's not a good sign. If replacing them solved the problem, then maybe it was not BCM related.
Just seems weird that the BCM woi=ould go bad just sitting there......

My money is on security system or bad gas

Last edited by derf; 02-01-2018 at 04:37 AM.
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Old 01-29-2018, 12:58 AM
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Thanks for the reply derf

The door switches werent stuck, but the buttons were loose and would lock/unlock on their own at times.

I charged their old battery and it has been holding voltage fine and been cranking over the engine Ok as I have been diagnosing it over the last few days. I'm going to take it out and charge it back up again. I know the battery is probably not in good shape, but trying to avoid investing money into a car that doesnt run.

Dome lights & chime work, and yes after bypassing the fuel pump relay there was fuel at the fuel rail. Plenty was pouring out when I pressed the fuel rail valve in.

The Security light is on all the time. Ive tried the Passlock relearn procedure a couple of times and it hasnt worked. The security light just stays on the whole time.

Just checked battery voltage and its 12.18V, so I'll put it on the charger a bit tomorrow and then try the security relearn procedure again. Then I'll check for Spark and see how that goes.

I havent replaced the door switches, I just took them out so not sure if not having them in will have an affect on the Security system?

Thanks again derf!
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Old 01-29-2018, 03:39 AM
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No, I never really sleep......

The lock chattering you mentioned is indicative of a weak battery OR the BCM going bad. We had another poster with the same symptoms causing overnight drain. I don't remember if it was an S or an L Series and I don't remember the resolution. Try searching on lock unlock security triggering randomly at night.
This other dude had a car that would randomly lock and unlock itself all night long, draining his battery]. I think sometimes the car would randomly go into alarm mode,, after which he'd have to do a passlock reset.
---------
A battery measuring 12.2V under no load tells you nothing about whether it is able to supply sufficient CURRENT needed UNDER LOAD to rotate the engine AND supply the electronics enough current at high enough voltages for things to work properly at startup.

Place a Voltmeter on the windshield face down, Attach the leads and snake them down and hook up to the battery. As soon as you turn the key, a good battery drops maybe a few volts while supplying enough voltage at a high enough current.
A bad battery's V will nosedive because there is very little charge stored=unable to supply necessary current. And if there is no V drop, there's no current flow

If your security light is on solid, security system thinks it's been triggered.
You MUST hook up another battery via jump start config and leave that other car running to perform the 30 min PASSLOCK relearn.
Good batteries don't always last through the procedure with sufficient V and current capabilities such that the procedure works. It's in the damn Saturn service manual. Hook up another source.

Even then, your weak battery may drag down the good one trying to charge itself.

PASSLOCK relearn WILL NOT WORK with your present battery as is--it needs a friend.
Follow the directions in the relearn procedure to the letter or it will fail
Put the switches back in and try again.
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Old 01-29-2018, 09:33 PM
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Your battery has to stay above 10.5 volts while cranking. It will take two batteries to survive a pass lock relearn. We have a jump cart at work with 4 group 31 batteries, it is hooked up for any computer reflashes.
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Old 01-31-2018, 10:48 PM
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Sounds like you guys really think its the Pass lock relearn. Its holding a steady 11 volts while cranking the engine over.

I hooked up the battery charger / tender while running the passlock relearn sequence, so we'll see what happens.

How important is the timing on the passlock relearn? I've been leaving the key in the ON position for 11-12 mins, but no matter what the Security light stays on. It only turns off when I turn the key off, then a few seconds after I turn the key to the on position, Security lights come right back on and stays that way till I turn the key off.

Thanks for all your input on this guys!
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Old 02-01-2018, 04:30 AM
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Just to make sure we are on the same page, here's the Passlock II relearn Procedure

(I've been referring to it sloppily as Passlock, but there were multiple versions developed with time. I believe the Saturns that used a Passlock system all used Passlock II)
------------------------
NOTE: DO NOT REMOVE THE KEY DURING THIS AT ALL, or you will have to start the procedure over from the beginning. (YOU NEED TO hook up a
battery charger battery charger
)


30 min passlock II reset procedure
_________
1) Press the
clutch pedal clutch pedal
in like you're going to start the car (if applicable)
2) Put the key in the ignition and turn it to CRANK
3) The car will try to start and then die
4) Leave the key in the RUN position as if the car started
5) You will notice on your dash that the "SECURITY" light is now on
6) Now wait approx. 10 minutes until the SECURITY light goes out (you wait on the light not the time)
7) When the light goes out turn the key from RUN to the OFF position (keep the key in the ignition) for 5 seconds
8) Repeat steps 1-7 two more times for a total of 3 cycles (30 minutes).
9) When you completed the third cycle you should have the key in the OFF position (per step 7)
NOTE: On the next ignition cycle the car will actually learn the passcode from the BCM
10) Push the
clutch pedal clutch pedal
in and now really start the car and it should start right up and run.

-------------
I had asked you if you were getting spark while cranking. You mentioned you'd check. But you never reported back.. Verdict?

This is important because contrary to what I said in error below (which I will have edited by the time anyone reads this) , PASSLOCK II only kills the fuel injectors when Security is triggered. NOT THE SPARK. That is why the car, w security tripped, can run for a few seconds then stall ---it has spark and fuel until the sec system informs the BCM that the car thinks it's being tampered with, and then it tells the bcm to tell the PCM to kill the injector pulse signals and the car stalls.

Have you checked the BCM and PCM fuses F INJ, and IGN too to ensure all are still good?

----------

The more I think about it, the signal to enable the fuel pump SHOULD occur regardless of whether security is enabled or not. It's the injector signals that get cut off by security, not the fuel pump.

So basically,

--security is tripped and will turn off the injectors 3 sec after successful or unsuccessful start
--your fuel pump never receives a signal to operate, so it won't start and run because it has absolutely no fuel from the time you start cranking it
--you can bypass that signal and run the pump and have pressure at the rail, but again, fuel injectors should cut out after 3 sec and stall -- but the part of this missing is the start and stall.
Air, fuel, spark, compression and some electronics.

IF BCM is not hosed, if you HAVE spark, the car should start and stall with the sec light on solid.
If the BCM IS hosed and is completely choking off the fuel indefinitely, it will never start with the sec light at solid on.

So try this:
1) Remove air inlet ducting at throttle body
2) Spray a small amount of starting fluid / ether into the throttle body. Don't go overboard, because if this does NOT work the first few times, you will build up a "charge" of unburned starting fluid, When/if it ever combusts, it won't be good for any part of the engine or exhaust system (or the intake if it backfires).
3) Run and quickly crank the car. If it sputters or runs, then stalls, you know spark is there but fuel is being inhibited by the security system. And you also know that the vehicle is capable of running (PCM ok at least),


You're basically bypassing PASSLOCK II with an alternate fuel source. The car should run until the starting fluid is consumed then stall.

If you don't get this far, check for spark again -- just be careful as starting ether will be in the air and having the spark check combust a cloud of it in your face is dangerous.
If you get this far, try the passlock reset again. If it does not work.......

Based on
---inability to reset PASSLOCK II
--door switches chattering on their own
--lack of fuel pump relay signal
--inability to use diag port due to improper grounding at BCM

my diag at this point would be bad BCM. Might just be corrupted firmware, Might be dead hardware.

It's cheaper to buy a junkyard BCM (correct part number for the vehicle AND pulled from an automatic or 5 sp to match whatever you have.
As long as you can do a PASSLOCK reset after you install it, and IT is not defective (many Saturns go to the junkyards for the exact issue you're having) , you should get your fuel pump relay signal back, security light off and start the car.
Since the BCM programming of the junkyard BCM is not the same (different options etc), some of your stuff might not work for right now but we'll address that.
If you get the car to start and run after a successful PASSLOCK II relearn (or 3 or 4), read the diag port to ensure it works.

Then it's off to the dealer to get the BCM flashed to match your car. The mileage displayed will be from the donor car so snap a pic of your current mileage and the starting mileage of the donor BCM in case you sell this (HINT).

May the horse be with you
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Old 02-01-2018, 11:54 PM
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I just tested for spark. Tried with the starter fluid method and it was weird, kinda semi turned over a little bit once. But when I tried to replicate it just cranked. So I pulled a plug out and tried to visually check, but it really didnt look like there was any spark happening. In the past its been pretty obvious when there is spark.

Yeah, I've followed those passlock II instructions exactly with the battery hooked up to the charger. Not once did the Security light change. I left it for 20 mins, on one of the cycles and it never turned off with the key in the On position.

I tested all the fuses in both fuses boxes for continuity. They all were in good shape.

So, that no spark thing. Could that be caused by a bad BCM? Also how can I go about sorting out what the correct part number is for this car? Its a 5 speed, so I'll make sure to get that. I'll call some local junkyards tomorrow and see if anyone has a BCM on island. If not I'm sure I can find out to get shipped out.
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