TxBenzIn

Thanks to this forum, I've enjoyed 2 months and about 1200 miles of some of the most fun I've had in a car. I"m not a car guy, but trying to learn.

The other day when driving I noticed the car felt sluggish and I looked at the Tach and it was 3500 or so and would not shift into the highest gear. I slowed way down, tried to move it to manual and it stayed in D. When I accelerated again, still would not shift into high gear.

I pulled over, shut the car off - Re-started it and it was normal for the next few hundred miles.

Yesterday, it did it again. Again could not go into manual mode. (Reboot helped). Later, I did get a significant "bump" when shifting (in automatic) from 2-3 like getting tapped on the rear end. One time, no other issues.

It did it agin today, and also when driving in manual it wouldn't shift out of 2 and the Check Engine light came on.

Since owning this car, I did have my local mechanic do a transmission flush a month ago. I have not checked the fluid, I do not have a scan tool.

Can you point me to some possible things to explore. I'm taking it to the shop tomorrow - (it's about a 10 mile drive - should I tow it, or drive it?)

2003 SL 500 / 70,000 miles.

MikeJ65

My first guess would be an accelerator pedal fault. This will cause a limp mode which will limit power and gear changes. I haven't tried to use manual mode in this limp mode, but it makes sense that it would be disabled. If it drive normal after a key cycle, I wouldn't have any issue driving it to the shop.

TxBenzIn

Ah interesting. Thank you.

TxBenzIn

just drove it to my guy - he’s gonna scan it and we shall see where we go.

it drove completely normal the whole way there. The check engine light was on - I’m assuming it’s persistent once it’s activated until reset?

aegea

I just found the accelerator problem, which is the TPS (Throttle Position Sensor) problem seriously caused my 7 speed to malfunction. I pressed the accelerator pedal and the rpms would only slightly increase. After a stop it might gain rpms more like normal intermittently. Before the TPS sensor symptoms were noticeable I had transmission problems occasionally limp mode. I occasionally left the negative battery cables disconnected overnight several times to enter transmission training mode. That kept me out of limp mode but i still had shifting problems. I just replaced the accelerator pedal assembly, and the tranny seems to be working well.

TxBenzIn

thanks for sharing!! Well done.

do you have a part number in case I end up down that road?

cdk4219

The early cars had a different part number than the later cars

aegea

I bought this salvage set of accelerator pedal assembly with brake pedal covers on ebay for $65 - 03-11 MERCEDES SL500 R230 SPORT GAS PEDAL BRAKE COVER SET 2303000104. 2303000104 is the part number. You may find an earlier post here that says the TPS is not serviceable, so buy the accelerator peddle assembly in which it resides.

TxBenzIn

This time it was the transmission conductor plate.

https://www.fcpeuro.com/products/mer...e-1402700861oe

Good as New!

aegea

I am glad your rollin' well. How much was the repair?

TxBenzIn

$180 for the part
$300 to put it in
then about $150 for fluid, filter etc.