throwing 4-8 codes need help ASAP
06-01-2007, 09:14 AM
#1
throwing 4-8 codes need help ASAP ive tried posting this in other sections but no one seems to know or they just arnt responding so ill try here. yesterday i was trying to use a test light and test for the positive wire that goes to my coil packs. nothing was wrong at the time. what i did exactly was turn the key to power everything but the motor and i then disconnected the connector and tested each pin till i found the positive. well i connected it back and then went to start the car and all of a sudden the car was running like absolute ****. lower idle no power at all back fires...? what the hell happened? it threw codes p0351-58 which i looked up to be coil circuit malfunction? so i tried swapping in a different set of coil packs to see if that were the problem and still no change. i need my car and i dont want to bring it to a stealership. what could have happen? is it possible to fry something in the pcm from unplugging the connector while key is turned in accessory mode? or could i have melted a wire somehow? shorted something out? i have noticed when i grab the bundle of wires that lead to the driver side coil pack and wiggle them all around that i can bring the motor to almost stall out...just by moving the wires around?
06-01-2007, 11:15 AM
#4
Originally Posted by C Murda
which fuse? i looked at the ones under the hood, maybe i missed one?
06-01-2007, 02:59 PM
#7
ok well i pulled the harness and all wires look fine no broken ends....im really starting to think i short cicuited something in the PCM but the only thing keeping from that conclusion is the fact that everything else works fine and i only throw codes from 0351-58 which are all coil circuit malfunction codes??? this is pissing me off...
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06-01-2007, 09:51 PM
#11
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Sounds like there's a short or bad ground somewhere. Ok, the pink wire is the ignition feed to the spark plug, one of the wires is the PCM reference wire (info for the computer), and the third wire is called the Ignition Control Signal or "IC Signal" (which is the one you were looking for in the first place). they're all different on each coil except the pink wire so you'll have to check each. Of course black is always ground.
How it works is the computer sends a signal through the IC Signal wire which closes the ground and triggers the coil to send voltage from the pink wire to spark the plug. The reference wire just informs the PCM of what just happened.
You should first check all of your connectors to make sure nothing is corroded at all and it is all still making a good contact. You said you checked for voltage by putting the multimeter terminal in the end of the plug, you might have just bent one of the terminals in the plug so it makes a poor contact. Make damn sure none of these terminals are bent. It is a pretty simple step and will save you time and heartache. It must spring back tightly so it grips the other connector tightly. Might even want to try that electrical grease to see if it makes a better contact for you. If these are all good carry on below...
The manual says to first check the voltage at that IC signal wire on the plug at the coils, if it's more than 1.0 volt it is shorting out to another voltage wire which you'll have to find and replace.
If it's less than one volt you have to disconnect the connector at the PCM (first disconnecting your battery) and check for continuity between the PCM connector and the coil connector. If you have bad continuity you have to find the break in the wire and repair it.
If you do have good continuity you have to plug everything back up, turn power back on, and check resistance from the IC Signal wire at the coil to a ground. If you have resistance the book says to check to make sure the connector on the PCM is in fact making a good contact.
If there's no resistance it says that wire is in fact grounding or shorting out somewhere. which again you'll have to find and repair.
Ok if none of this works the book says to replace the PCM.
as for schematics:
Cylinders #2, 4, 6, and 8... the pink wires are connected together and the PCM Reference wires are all connected together. The pink wire goes to the fuse, then to the power distribution block, and the reference wire goes to your PCM.
Same goes for cylinders #1, 3, 5, and 7. except for the reference which is a different pin on your PCM.
I was going to give you all the PIN numbers but I realized you have a 2002 and my book is for 98's only. The PINs are completely different, sorry.
Good luck and let me know what happens. I know it's a lot of information and "shooting" wires but that's what wiring is all about lol. I've been doing it for the past week trying to fix my fuel gauge. It is not fun. But if you need more info let me know, these manuals give a shitload of info.
If none of this works...
How it works is the computer sends a signal through the IC Signal wire which closes the ground and triggers the coil to send voltage from the pink wire to spark the plug. The reference wire just informs the PCM of what just happened.
You should first check all of your connectors to make sure nothing is corroded at all and it is all still making a good contact. You said you checked for voltage by putting the multimeter terminal in the end of the plug, you might have just bent one of the terminals in the plug so it makes a poor contact. Make damn sure none of these terminals are bent. It is a pretty simple step and will save you time and heartache. It must spring back tightly so it grips the other connector tightly. Might even want to try that electrical grease to see if it makes a better contact for you. If these are all good carry on below...
The manual says to first check the voltage at that IC signal wire on the plug at the coils, if it's more than 1.0 volt it is shorting out to another voltage wire which you'll have to find and replace.
If it's less than one volt you have to disconnect the connector at the PCM (first disconnecting your battery) and check for continuity between the PCM connector and the coil connector. If you have bad continuity you have to find the break in the wire and repair it.
If you do have good continuity you have to plug everything back up, turn power back on, and check resistance from the IC Signal wire at the coil to a ground. If you have resistance the book says to check to make sure the connector on the PCM is in fact making a good contact.
If there's no resistance it says that wire is in fact grounding or shorting out somewhere. which again you'll have to find and repair.
Ok if none of this works the book says to replace the PCM.
as for schematics:
Cylinders #2, 4, 6, and 8... the pink wires are connected together and the PCM Reference wires are all connected together. The pink wire goes to the fuse, then to the power distribution block, and the reference wire goes to your PCM.
Same goes for cylinders #1, 3, 5, and 7. except for the reference which is a different pin on your PCM.
I was going to give you all the PIN numbers but I realized you have a 2002 and my book is for 98's only. The PINs are completely different, sorry.
Good luck and let me know what happens. I know it's a lot of information and "shooting" wires but that's what wiring is all about lol. I've been doing it for the past week trying to fix my fuel gauge. It is not fun. But if you need more info let me know, these manuals give a shitload of info.
If none of this works...
06-02-2007, 07:20 AM
#12
so lemme make sure im clear on what you did. You just hooked the test light to ground and then tested for power on the harness side of the connector? the only thing i can think of is that when you were testing the leads when you hit the 12 volt source the test light was somehow touching the other pin that runs to the PCM and you sent 12 volts to the pcm and shorted out that circuit. thats the Only thing that i can think of. unless you missed a fuse. lemme hunt around SI and see what i can find for ya