95 SL Auto Transmission Shifting Delay

**89HatchbackLxi** · 03-20-2015, 04:16 PM

Ok, so for the past few months I've noticed my car has started developing a weird delay or sudden quick jump with shifting, -this isn't bad enough to cause the car to be a road hazard or anything, but it's very very irritating when it occurs.

The weird part is, the car only does this once the engine is fully warm or if its a warmer day outside. (like 75+ F outside) (I determined this because it never seems to happen in the morning on my way to work, but it does sometimes happen on my way home from work). So, living in CA, the car has started doing this more now that it's getting warmer outside. What the heck could be causing this? Is there some kind of temperature sensor related to my transmission shifting that could be going bad?

The transmission is perfectly fine when it's not warm out, or when the engine is not yet fully warmed up, so I don't think the transmission itself is going bad. It's got to be something temperature related.... I just can't figure out what it is since I have little mechanical background, and I don't want to take it to a transmission shop until I have an idea what it could be, cause they'd have to keep the car for a day or two to run some tests on it.

**89HatchbackLxi** · 03-20-2015, 04:18 PM

Also, I feel like the acceleration is also affected around the time the weird shift problem occurs, like its slightly bogged down. It's almost like a hiccup, then it catches itself, and doesn't do it again until the next day.

**IPD** · 03-22-2015, 09:54 AM

try switching from PWR to ECON or vice versa. If this fixes it, it might be a TCU issue. If not--and you're still driving the same way--then it could be something mechanical.

**89HatchbackLxi** · 03-23-2015, 12:21 PM

Thanks for the response.

I usually drive in ECO mode but I'll try switching to PWR mode and see if the issue still occurs.

**IPD** · 03-23-2015, 01:28 PM

Originally Posted by 89HatchbackLxi

Thanks for the response.

I usually drive in ECO mode but I'll try switching to PWR mode and see if the issue still occurs.

Same, but I have noticed at times that ECON seems to act "janky" and PWR seems to alleviate that.

**89HatchbackLxi** · 03-24-2015, 03:47 PM

Drove car in PWR mode yesterday and I had no issues with the transmission acting "janky". However, the temperature was a bit cooler yesterday and today so it may have also been that factor which prevented the triggering of jankiness in the transmission. Issue is also intermittent, so I'll keep it in power mode the rest of the week to do more testing.

If this does fix the issue is there anyway to reset the TCU? Or would replacement be the only option?

Also, a bonus question. My gas light seems to no longer be illuminating when I'm low on gas, and so I think it's burnt out. Is this light supposed to momentarily flash when the car is started, as various other lights on the instrument panel do, or does it remain unlit during startup?

**89HatchbackLxi** · 04-07-2015, 03:37 PM

Have been driving the car in ECO mode on the way to work in the mornings (since it's cooler out) and then in PWR mode the rest of the day. I haven't experienced the weird shift delay since I've started doing this. Thanks for the suggestion! I'm amazed something so simple actually worked!

However, does this mean my TCU could be going bad? I swear the issue is somehow related to temperature. Maybe a temp sensor that's only used/or is set to check for a different temp when in the ECO setting or something?

I'd prefer to be able to use ECO mode for it's better MPG (as my car never used to have this issue and I almost always drove it in ECO mode before), any thoughts on what the issue could be caused by?

**IPD** · 04-08-2015, 05:31 AM

Originally Posted by 89HatchbackLxi

Have been driving the car in ECO mode on the way to work in the mornings (since it's cooler out) and then in PWR mode the rest of the day. I haven't experienced the weird shift delay since I've started doing this. Thanks for the suggestion! I'm amazed something so simple actually worked!

However, does this mean my TCU could be going bad? I swear the issue is somehow related to temperature. Maybe a temp sensor that's only used/or is set to check for a different temp when in the ECO setting or something?

I'd prefer to be able to use ECO mode for it's better MPG (as my car never used to have this issue and I almost always drove it in ECO mode before), any thoughts on what the issue could be caused by?

I'm not an electrical engineer. If Shooter83 is around, I'd ask him--he's the only guy I know who keeps electrical diagrams as bathroom reading materials. Perhaps someone with more expertise than I can chime in.

As to the fuel efficiency, this is irrelevant. All ECON/PWR does is change the rpms the transmission shifts at, and its willingness to "kick down" rapidly. If you're driving in a regular, non-aggressive fashion, you should not see any noticable difference in fuel economy in one mode vs the other.

I'm not sure on the fuel light, I haven't driven mine in several years (I'm not stateside). I think mine would normally only come on once the needle was pretty much ON the "E".

If someone can chime in on the TCU, I might learn something myself. I had the same problem (still do on occasion), and it was Shooter83 who turned me onto the mode switching.

**89HatchbackLxi** · 05-01-2015, 03:38 PM

Update: As the summer begins to approach and the weather has gotten a good 15-20 degrees warmer during the day, the vehicle has started having the same issue again, even with PWR mode on. PWR mode seemed to help originally, however it seems it was only so effective as the outside temperature increases...