98 Sc400 Throttle Control Unit

[98sc400az]

Hi, I'm new here and glad to have found you. I have a perfect white 98 SC400, never any problems until today when I went into the dealer to replace the dead battery in my key. As soon as I drove away, the engine light came on and the trac light started flashing. So back to the dealer where I had just spent $4 to be told the throttle control unit is failing. A new one would be $1300 installed! This is so weird, never any problems before.

So can anyone tell me if the car is safely drivable? Also, do I have any choice in replacing this part ($1057 for the part alone)? Until today, I had no symptoms, no surging.

Thanks... I'm a mechanically challenged female. This is my second SC400. Bought my first one, a 92 out of the brochure. So it's about time I started learning a little about this car before the dealer eats me alive!

[JIBBBY]

Trac control is over rated... When it goes out like it is with you it is automatically disabled and reverts to normal driving conditions... I wouldn't spend to much to fix it unless you live in crazy weather...

[98sc400az]

Trac control is over rated... When it goes out like it is with you it is automatically disabled and reverts to normal driving conditions... I wouldn't spend to much to fix it unless you live in crazy weather...

Not the trac control, it's the THROTTLE control sensor which I think also controls the trac. It's the throttle I'm worried about. Thanks for the reply, sorry I wasn't clearer.

[jzz30]

i think you should get a second opinion. you should try go to checker auto parts or something and get a scan of what the engine code is. then report back to us what it is.

[SirSam]

Are you referring to the Throttle Control Actuator or Throttle Position Sensor? I've never heard of these going bad myself.

Throttle Position Sensor: $130 at local store

Throttle Control Actuator: $822 at local auto store

[schott1984]

I've had throttle position sensors go out on two different cars. Not Lexus though. Beside the point though. I don't think either of these parts would be hard to replace. I know the TPS wasn't on the other cars.

[98sc400az]

I've had throttle position sensors go out on two different cars. Not Lexus though. Beside the point though. I don't think either of these parts would be hard to replace. I know the TPS wasn't on the other cars.

Thanks to you all for the help. I'm just back from getting the car back from the dealer. They swore the whole throttle unit needed replacing. I asked if it just needed a cleaning, but they said "no"... just pay us $1300 and we'll fix it, then we can do the 90k maintenance and charge you another $1400. Needless to say, I left!

Then went to Autozone and they gave me the code P0121 - which says to replace the TPS. Dealer claimed this wasn't the problem. Anyway, once I started up again, no engine light came on and I drove back 3 miles with no light. So now do I think this will happen again? I got the name of a good mechanic from Autozone and am going to call him. Anyway, a tale of how dealers can take advantage of gullible people.

Again, thanks so much for the advice.

[schott1984]

Good work! Glad to see you evaded the stealership haha. Yeah that's pretty bogus. How much did the TPS cost you then?

[98sc400az]

Good work! Glad to see you evaded the stealership haha. Yeah that's pretty bogus. How much did the TPS cost you then?

Not ordered the part yet, but seen it online for $130, about the same as SirSam wrote. Stealership, I like that!

[schott1984]

Heh, yeah I stole it from someone else on here that has something about stealership in their sig. So, the light is off now, even though you did nothing to remedy the problem?

[98sc400az]

Heh, yeah I stole it from someone else on here that has something about stealership in their sig. So, the light is off now, even though you did nothing to remedy the problem?

So far, yes, no light. But I think the problem is real. I'll report back once I see the mechanic. Thanks!!

[schott1984]

Well yeah, if you got the TPS code, it's likely going bad. On my cars is was evident in the way they operated though. And the second one was actually wiring TO the TPS, no the sensor itself.