1997 Buick Riviera Codes\Transmission Questions

Hi there! (I apologize in advance if I over-explain, I’m just trying to be as detailed horough as possible)

I have a 1997 Buick Riviera V6 3.8L Supercharged. From what I’ve gathered it seems as though the car doesn’t really want to shift into gear, and seems to go into reverse fine, but doesn’t want to go. The car was my dad’s who passed away 2 months ago and he had a code reader so I’ve been able to read the codes off of it, which after a lot of reading I gathered that the two relevant codes were P0753 and P0758.

For the sake of making this a bit easier, I’ll list all of the codes I’ve got so as there’s no missing information. I wasn’t sure until recently about the codes P1xxx+ because from what I read are dealer specific, but I think I got them all now, and I kind of wish I knew before taking it to the shop, but here are the codes I’ve got:

P0135 -> Oxygen Sensor Heater Bank 1 Sensor 1
P0341 -> Camshaft Position Sensor A Circuit Range/Performance
P0753 -> Shift Solenoid A Electrical (Also known as Shift Solenoid 1-2)
P0758 -> Shift Solenoid B Electrical (Also known as Shift Solenoid 2-3)
P1406 -> EGR Valve Pintle Position Circuit
P1655 -> EVAP Purge Solenoid Control Circuit
P1860 -> TCC PWM Solenoid Circuit Electrical

I think there were a couple more oxygen sensor related ones, though I need to find my paper where I wrote those down, but as far as I know they wouldn’t have a major impact like this.

Basically the steps that I have taken so far is buy the 2 shift solenoids, transmission fluid, and whatnot, take it to the shop and have them replaced, the transmission fluid drained and refilled. The guy had said that the transmission fluid was dirty\black, which in my reading was a possible cause to the problem I’m having, but he said it did nothing. As of the moment the car is still in the shop, and I’ve got to go there and pay the $405 and get back a currently unusable car. He says that I need a new transmission, which he says will be at least $1000.

I’m nowhere near as adept at dealing with cars as my dad was, but the person I’m staying with is, and could probably replace the transmission himself if it’s absolutely necessary, we could pick one up at the junk yard for $75-$150. However I’m looking for other opinions what I might do. My dad was an electronics technician, so he had a multimeter, tons of tools, and whatnot, so if there’s something I could test that someone says I should test, I could do that.

I bring up the multimeter, as in the codes I keep seeing “electrical” and “circuit” which when I hear that, I first think wires and electronics.

The car itself was running perfectly fine, it was a snowy day and it started acting up as I’ve explained. Prior to this I do believe that there might have been some issues with some wires\relays or whatever as when my dad was still around the car sometimes didn’t want to start and it was because of something that came loose that was underneath the backseat, which I believe was a wire or relay. I also believe my dad may have done something to bypass the traction control to force into off because it would cause some weird issue with it on, and he didn’t want to have to keep turning it off every time he started the car.

Anyway, any information or help is greatly appreciated, I’m not an expert when it comes to these things, which I know might seem like an immediate red flag to step away, but the guy in the shop recommended I scrap the car, and I do NOT want to do that. It was my dad’s car, it’s the last thing I got.

Thanks in advance!

If the solenoids were replaced with no improvement it will be an internal transmission issue. That being the case the transmission would need to be overhauled or replaced. This will be a difficult job to do without a lift as the cradle has to be removed and the engine supported from the top. From the codes you have listed it also looks like the egr valve and an oxygen sensor are failing, both were common issues.

Why did the shop say the car was scrap? Beyond the transmission how is the overall condition of the car?

Well, the shop said that it would cost at least $1000 to replace the transmission, and I currently have to pay I believe $405. Beyond that, the car needs some new tires and a front end alignment, which I already knew, and brakes. However those aren’t a big deal to me considering that’s relatively easy work in comparison.

He says that with all that money it’s worth more than the entire car. Which that is true assuming I were to pay $1000+ to replace a transmission, which no way, I’ve got the tools, I can do that. The main reason we took it to the shop was because it’s dead winter at the moment.

The reason I mentioned the other codes is because I was wondering how much would they possibly play a role with the current issues.

I DO want to mention that the shift solenoid codes were showing up before the car was having the problems. Maybe a week or two before, and it all of a sudden went kaput. I also had a van which the engine seized on which we thought it was a battery\ignition issue at first and we ended up jumping it with the car, and that’s when I noticed the new codes for the shift solenoids.

So it’s pretty much absolutely certain it’s an internal transmission issue?

I’ve got a 95 Aurora which is similar to the Riv except for the engine. If your shift solenoids go, it should go into default mode which is 2nd gear. If it doesn’t shift into gear, it sounds more like internal problems such as the clutches or torque converter. I’m not a big fan of used transmissions and would rather have that one overhauled but at a cost of $2-3,000. The codes other than the A, B and TCC really should have nothing to do with the transmission. A good shop though should be able to determine the problem and if it is something with the body control module instead which I doubt. Sounds like you have to decide if you want to keep it and pay the price or get rid of it. Nice cars though.