multiple problems - need troubleshooting help

[seanlong]

Hello,

I left the country for 6 months (military) and when I came back, my TransAm is falling apart. My service manual is in storage so I need some help tracking a few problems down.

First, the TCS light came on after a car wash. The dealer service guy pulled the code C0239 Spark Retard Circuit and said it would be very expensive to troubleshoot, so I didn't have him do anything. Any ideas where to start or even what wiring harnesses could affect this? Or is there really a problem with the ignition?

Second, not sure if it's related to the first, I get a heavy shuddering when braking at freeway speeds. My tools are with the service manual (in storage) so before I break out the OEM emergency jack and start pulling wheels off the hard way, I thought one of you guys might have a suggestion where to start first. My impression is that the shuddering is in the right rear.

The dealer recently replaced my fuel pump using the full drop rear axle method, so maybe he hung the rear axle wrong and that's causing the shuddering?

Last, and hopefully easiest to fix, I think the cooling fan that is supposed to come on when I turn on the A/C isn't running. There are 3 solenoids in the fuzebox labelled fan1, fan2, and fan3, but without the manual I'm stumped. I'll look for unplugged wiring harnesses but again I was hoping someone with a manual could help me with the troubleshooting tree for this one.

edit - I think the fan problem is really a cooling problem. I ran the car in the garage and after checking for loose connections and blown fuses, the fans come on correctly. Initially the temp will sit right around 180 on the gauge with the AC on just like it has done for the last 8 years, but after idling it for 20 min the temp creeps up to around 200 and holds there. I had a problem with the low coolant light coming on incorrectly (radiator was full) so I had the cooling system flushed and refilled, but it's still running about 20 deg warmer than it used to. It used to sit right at the thermostat rated temp whenever I was driving or whenever the fans were running. Now, it sits at 190-200 most of the time unless I'm on the freeway, and then it drops back down to the thermostat temp of 180ish.

I'm in Dallas near Farmers Branch so if anyone around here can recommend a good nearby shop or dealer to help me out with this stuff, that might help too.

Thanks in advance!

[SeVeReDiStOrTiOn]

Look for any debris blocking the front of the radiator and condenser...also make sure there's not a lot of compacted dirt in the radiator cooling fins. Wouldn't hurt to put a new radiator cap on if you never have.

When you turn the a/c on the fans should switch to high speed...it's a lot louder then the low speed setting

The shuttering in the rear could be a warped rotor...sometimes when you apply the parking brake too hard on a hot rotor it'll warp. Could be a loose caliper...does it make a clanging sound?

Not sure about the TCS...my best guess is check the sensors in the rear and make sure they're not broken or missing since you did just have the rear dropped.

[seanlong]

No clanging with the brakes, and sometimes it does feel like a badly warped rotor even though I don't get that surging feel at low speed you usually get with warped rotors. The thing is, the brake discs went 110,000 miles without warping and I turned them barely 9,000 miles ago when I got a new set of pads so I am very disappointed if it's a warped rotor. They were a one in a million set of rotors that never warped or had much scoring even after several autox seasons, and I only refinished them because I put on a brand new set of pads and wanted to get at least another 50k miles out of them.

There is only a tiny bit of debris in front of the radiator, unless there is stuff trapped between the engine and AC radiators. I'm wondering if maybe I went too long between coolant changes and the radiator is partially clogged.

If nobody knows what that TCS code means, I guess I'll have to wait until I get my service manuals out of storage before I can start troubleshooting that problem.