Technical Throttle body fault code

[LorenzovD]

Dear Fiat Fiat Forum,

Recentely my Fiat Stilo 1.6 (2004) failed on me while driving. It suddenly dropped speed and the rpm wouldnt go much higher then 2000rpm. The check engine light came on. I scanned the ECU and I got Code 0638 - Throttle actuator control, Bank 1 -range/performance problem.

I started to notice that the car started to accelerate poorly since a couple of weeks. Maybe this has anything to do with it?

Also, The car does not reach the 90 degree mark while driving. It stays a little to the left. When the care is at Idle infront of a traffic light for example the car reaches the right temperature.When I start driving again it drops. I have changed the Thermostat and the Temperature sensor already.

I hope there are some people that could help me.

Thank you in advance!

- Lorenzo

 

[Ralf S.]

What engine do you have? In the petrol engines there should be two sensors on or near the throttle body. One is the throttle position sensor and the other is the idle control valve.

Find and extract the TPS and then give it a good clean. Be careful removing it or poking around inside it.. some of them consist of a small metal spring that turns a potentiometer so it's easily damaged if you stick a screwdriver in there, expecially if it's filled with soot/gunge so you can't see the small parts inside.

Also check for physical damage/wear... make sure the dibber turns properly when the throttle opens and closes.

If you end up replacing the TB with a new/second-hand one (if that's the cheapest/easiest way to fix it) then there is probably a reset procedure involved. You *could* try the reset procedure on yours but I dunno whether that will only fix the symptoms until it gets "unsynchronised" again (if there is a physical fault with it).

The thermostat sounds weird... but it's definitely not closing fully if the car runs cool. What brand did you use? Behr and Facet is good. Circoli maybe less good (I seem to remember some of those used to split apart... but it might have been a different brand).


Ralf S.

 

[LorenzovD]

Thank you for your reply!

I got the 1.6 103 Horsepower petrol engine. 182B6000 is the motorcode.

I am going the check the sensor, however ever since this happend the car feels very slow... Also, it wont go faster then +-150km/h.

I changed the thermostat for a maxgear one because of the problem with the temperature. The car does get warmer faster then it did before the thermostat change, but it still doesn't get to the right temperature. Basically the problem still exists. I also swapped the temperature sensor but this didn't work.

 

[Ralf S.]

Your thermostat, if it has "Max" in the name could be a "sport" or "racing" type.

If so, it would be designed to open earlier, since it will be marketed as something you can fit to a monster-tuned car making 200bhp.

A standard thermostat will start to open at c.86C and be fully open by 90C. If the temperature reaches 92C then the fan will come on, and stay on until the temperature drops to 88C.

A more "sporty" thermostat will start to open around (e.g.) 84C and, because it's expecting a huge rush of heated coolant, it will be fully open around 88C. The fan is controlled by the ECU so there's no change in how that works.

So, your temperature will stabilise at a lower temperature e.g. 88C instead of 90C. It's not too serious, other than a hotter (90C) engine will improve your fuel economy a little. As long as your car gets to "88C" and stays there, then it'll be okay.


Ralf S.