# Beetle 1.8 Throttle body codes... ecu and tb are good.



## nnos_rs4 (Nov 6, 2011)

Hello everyone,
I have a 2000 Beetle with the 1.8t and it is throwing the following two codes:
1. throttle valve actuator malfunction
2. lower stop not reached

Car performs like it needs a tb adaptation. Topping around 2k rpm.

I have another ecu and another throttle body. Both are good and both were put on the Beetle to no avail. (Existing tb and ecu were installed and adapted to my other Beetle of the same year and worked perfectly. Ruling them out, but tried the replacements nonetheless.)

When ignition is set to on, the codes listed do not clear, so adapting is not working. The tb is receiving power. However, when car is switched on, the tb valve opens slightly and flutters a bit. On my other beetle (the good one), the same throttle body just makes one slight movement when the key goes from off to on with no fluttering.

There was a major problem when I first went to inspect the ecu. Water had gotten to the right (smaller) plug and buildup was heavy between a few pins. I'm guessing the problem started from there. Need help tracing. I continued to the next plug beyond the ecu, which had also taken a small bath at some point or another. I cleaned the pins and harness at those points and reconnected. The shorts are the reason why I suspected the ecu may very well have been fried. But it's not. 

Here's a picture of the water damage:









Fuses are good. 
The gas pedal is fine also.

I wasn't able to raise the car much at the time to inspect the 02 wiring, but I did unplug the 02 sensor wires in case there was a short beyond the plug. No difference. (Doesn't a shorted out 02 wire fry the ecu anyway?)

Speedometer doesn't work. It occasionally bounces. Any ideas?


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## Rockerchick (May 10, 2005)

Can you provide the actual code numbers?


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## nnos_rs4 (Nov 6, 2011)

These were the codes:

17953 - Throttle Valve Controller: Malfunction
P1545 - 35-00 - -
17973 - Throttle Actuator (J338): Lower Stop not Reached
P1565 - 35-00 - - (This one sometimes doesn't come up, but is usually there.)

The car does have traction control, and I'm guessing the vehicle speed sensor is bad, since speedo is wacky and od isn't counting. (Gas gauge and remaining instruments are fine.)
Is it likely that since it has traction control, a bad VSS may be causing the tb codes?


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## nnos_rs4 (Nov 6, 2011)

Okay I ruled out the vss. It was a bad connection that didn't affect anything. 

I checked resistance on wires from tb to the ecu. All were good.

After 2hrs:
It appears that when I was originally cleaning the pins in the ecu harness, I may have spread them open a bit too much. I will splice in a new harness end and update.


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## nnos_rs4 (Nov 6, 2011)

*Wiring Schematics Beetle 1.8*

Put in another wiring harness to the ecu and checked it all the way back to the tb. Perfect. Still same code. I tested the gas pedal in another beetle and it works perfectly. Does anyone have a wiring diagram/schematics for the ecu, tb, and pedal?

(edit) Check that. Here are the schematics for a VW Beetle 1.8T for anyone who may need them.


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