Mechanics

02 WON'T START

2002 Saturn SL2

Electrical problem
2002 Saturn SL2 4 cyl Front Wheel Drive Automatic 70,000 miles

Helping my brother repair his 02 SL2. It's been sitting for several years and now he's getting it on the road. It cranks but won't start. Replaced the plugs and wires since they needed to be changed anyway, no luck. Checked and it doesn't have spark. Had the ignition coil packs checked and they're good. Tried hooking a diagnostic scanner up to it but it doesn't connect with the computer. I suspect the computer or the wiring to it. Anyone have a wiring schematic or any other suggestions. BTW I don't know if the fuel pump is pumping either. If the computer isn't powering up would the fuel pump work?
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Brahmabull
August 3, 2010.



The first thing I would check is that the battery is good and charged the battery cable's are clean and tight. Make sure all the fuse's are good in the under hood fuse box especially the ecm one also check all the fuse's in the inside fuse box. When you first turn the key to the run position go to the inside fuse box and see if the fuel pump relay click's on then off.

Saturntech9
Aug 4, 2010.
Thanks for the help SaturnTech9! The battery is charged and the connections are tight. I checked all the fuses under the hood and in the car and they are all good. I checked out the fuel pump relay in the car and it didn't click when we turned the key to " run". So I unplugged the relay from the socket and tested the relay and it's good. I'm familiar with this relay. I put 12VDC across terminals 85 and 86 and the relay clicked. So I put my meter on the socket at 85 and 86 and didn't get anything when we turned the key to " run". What controls that relay? Also, I didn't see a fuse labeled " ECM" under the hood but did see " PCM". Is that the same thing or do I need to check something else? Thanks in advance

Tiny
Brahmabull
Aug 4, 2010.
You said the scan tool doesn't talk to the computer we need to start there with all that you describe. No voltage to fuel pump no spark. Yes you would check the pcm fuse and make sure you have power to both sides of it with the key in the run position. If your scan tool doesn't have batteries in it will the scan tool power up off the car?

Saturntech9
Aug 5, 2010.
Yes, checked both sides of the PCM fuse and both sides are +12vdc with the key on and go to -12vdc with the key off. I'll get my buddy's scanner and try it without the batteries tonite. Is the PCM and ECM the same thing? Does the ECM/PCM turn on the fuel pump?

Tiny
Brahmabull
Aug 5, 2010.
Alright here's the difference if your car had a manual transmission you would have a ecm engine control module. Since you have a automatic transmission you have a pcm power train control module when ever you combine the engine computer and the transmission computer together like they did on your car then it's a pcm when they have the engine computer by itself it's a ecm. Also when they have the transmission computer by itself for a automatic it's called a tcm transmission control module. Let me know if the your buddies scanner powers up.

Saturntech9
Aug 5, 2010.
OK, thanks. I tried my buddy's scanner. I took the battery out of it and it did try to connect with the car but ultimately it said " no response from vehichle". The scanner is an Actron Super Auto Scanner.

Tiny
Brahmabull
Aug 5, 2010.
Should I assume since the scanner powered up from the car the connections are good? Is there a way to check the pcm off the car?

Tiny
Brahmabull
Aug 6, 2010.
That just will test if your dlc has power and ground to power up the scan tool. On your car it has to go thru your a few computer's to get to your pcm.I emailed you the trouble tree and wire diagrams so you can see what's going on. Just so you know the first thing the trouble tree asks if you can talk to the bcm/body control module your buddies scanner can't talk to bcm. So the only thing your buddies scanner can read code's from and see data is the tcm and pcm. So you will have to wing it.

Saturntech9
Aug 6, 2010.
Also make sure all fuse's are good inside and out check and make sure the bcm fuse has power to both side's of it.

Saturntech9
Aug 6, 2010.
Dont see a fuse labeled bcm. Could it be called something else?

Tiny
Brahmabull
Aug 7, 2010.
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