01 SC2 codes, 0302,0405, 1301

[theunpaidBill]

Morning!

So I have an 01 SC2, DOHC, manual transmission that I use as my commuter car. It does roughly 400 miles per week. It's got 277K miles on it, and runs better now than when I got it 4 years ago. Uses about a quart of oil every 4000 miles (I run full synthetic and change it at 6K).

All in all it's a great car.

It's started idling a little rough when it's hot. I changed plugs and plug wires, but the codes came back, so I'm asking for a second opinion on step 2.

Codes are:
P0302 - Misfire cylinder 2
P0405 EGR flow sensor A circuit low input
U1301 Class 2 short to battery

I thought the 0302 would be cured with plugs and wires, as it definitely needed them. My next plan for it is replacing the coil pack. Should I just do the one or hit them both while I'm doing it?

The research around here I see says the 0405 is not unusual for an aftermarket EGR valve because they are not that great. Is my best option to buy one with a warranty and just replace it whenever it starts doing this? Autozone has been solid with warranty replacements.

I don't know about that 3rd one, could it be caused by the EGR issue? I replaced the battery a few months ago and haven't had any problems with it since.

[2NDSOUT]

Originally Posted by theunpaidBill

Morning!

So I have an 01 SC2, DOHC, manual transmission that I use as my commuter car. It does roughly 400 miles per week. It's got 277K miles on it, and runs better now than when I got it 4 years ago. Uses about a quart of oil every 4000 miles (I run full synthetic and change it at 6K).

All in all it's a great car.

It's started idling a little rough when it's hot. I changed plugs and plug wires, but the codes came back, so I'm asking for a second opinion on step 2.

Codes are:
P0302 - Misfire cylinder 2
P0405 EGR flow sensor A circuit low input
U1301 Class 2 short to battery

I thought the 0302 would be cured with plugs and wires, as it definitely needed them. My next plan for it is replacing the coil pack. Should I just do the one or hit them both while I'm doing it?

The research around here I see says the 0405 is not unusual for an aftermarket EGR valve because they are not that great. Is my best option to buy one with a warranty and just replace it whenever it starts doing this? Autozone has been solid with warranty replacements.

I don't know about that 3rd one, could it be caused by the EGR issue? I replaced the battery a few months ago and haven't had any problems with it since.

I'll take a stab at your codes. If you have replaced the plugs and wires- did you make sure they were properly gapped at .040?

Also- The Saturn S-Series engine, actually runs better on the NGK Copper plugs then it does on Platinum or Iridium Plugs... If you dig in a bit on the site- you'll see people go either way on them- but the general consensus is that the NGK Copper plugs are better. The Platinum and Iridium plugs run too hot for the S-Series engines.

Here is a thread on the EGR P0405 code. There may be some good info here.
http://www.saturnfans.com/forums/sho...d.php?t=175470


As for the U1301 Code- if you have something plugged into the Cigarette Lighter- it could be causing issues with your electrical system. I would also check with a voltmeter; the voltage you have going on the battery.
With the car sitting- the voltage should read 12 Volts.
With the car running- the voltage should read 13-15 Volts.
http://www.saturnfans.com/forums/sho...d.php?t=198731

With 277K miles on your engine- and if you haven't replaced the coil packs- it is best to replace them together. I would even go to the extent of swapping out the ICM (Ignition Control Module)- which is the "square electrical plate" that the Coil packs are attached to- if it hasn't been replaced before. They are held in with either 8 or 10mm long bolts that attach into the top of the engine block, and can be a bit of a pain, if you have bigger hands, especially since one of the bolts, is partially blocked by the A/C Hose. I once had issues on my 99 SL, where I was getting a misfire code- and it turned out that the coil packs, ICM, Plugs and wires- ALL needed to be replaced.

As a final thought- with that much mileage and you driving 400 miles/week; it may be beneficial to make sure that you have proper compression on the cylinders. The standard for compression should be 180/185-200 PSI across all 4 cylinders. If you have a lower reading on Cylinder 2- then it may be time to think about an engine rebuild, or putting a replacement engine in your car.

Hope this info helps.

[theunpaidBill]

Thanks! Unfortunately it seems any type of copper plug is in short supply in my town, so it got the basic Bosch platinums. I'll have to read up on the 405.

The weird thing about the short code is I don't have anything plugged into the power port, and the radio has been in there for years. I'm hoping it's caused by the EGR valve and I fix one and get both.