Leon MK1 1.9 TDI 66kw - Power loss

[Filip]

Hi everyone,
I'm new at this forum and I'm love with my recently bought Leon.

Seat Leon MK1 1.9 TDI 66kw manual transmission.

The vehicle doesn't go above 120km/h and 3000rpm.
I went to few repair services and they weren't able to resolve this issue.

I've replaced the MAF sensor, and there was small speed up but on the lower gears (better start).

I've connected to VAG-COM and these are the engine errors:

2 Faults Found:
18062 - Please check DTC Memory of Instrument Cluster
P1654 - 35-10 - - - Intermittent
17945 - Fuel Shutoff Solenoid (N109): Malfunction
P1537 - 35-00 - -

The last repair service, after playing a little bit with connectors, disconnected the Coolant Temperature Sensor and clear the errors. After this, the vehicle was running great. I was able to feel it the turbo running on my engine. But the repair service wasn't able to fix the issue with the coolant sensor and left me only with finding the cause of power loss, not resolving the issue.

I've connected to VAG-COM again:

2 Faults Found:
18062 - Please check DTC Memory of Instrument Cluster
P1654 - 35-10 - - - Intermittent
17664 - Engine Coolant Temp Sensor (G62): Open or Short to Plus
P1256 - 35-10 - - - Intermittent

The previous error (for shutoff solenoid) was dismissed.

I've played few times with connecting and disconnecting the coolant sensor.
There were same results:

If the coolant sensor is attached, the car have power loss, and on starting the engine it's a little bit noisy (1 second) make some black smoke. It went to 1100 RPM and then back to 900 RPM.

If the coolant sensor is detached, the car is going great, no black smoke no noise on start.

The coolant sensor was replaced previously.

Any ideas of what can cause the issue?

 

[Connorg115]

Was the coolant temp sensor a genuine part or an ebay part?

If it was an ebay part then id get a genuine one

Sounds like you might have isolated the problem yourself!

 

[masterfrodo]

I changed my coolant sensor last year. Since then the temp gauge reads 1/4, and very occasionally will reach halfway. But, doing a temp check, it reaches normal temp and stays there, so not sure whether I have a faulty sensor, or something in the dash - or even if a dodgy thermostat would do this

 

[Filip]

I've replaced the coolant temp sensor with new - original one. I can see the temperature values on VAG-COM and the dash, they are nearly the same. Once the motor is warm-up, the temperature is before 90 on dash, and 90.9 on VAG-COM.

Any other parts that can cause this problem?

I'm not sure where the fuel solenoid is located?

 

[Connorg115]

The temp gauge in the car is very vague, as long as the temperature is sticking around 90 on vcds then all is good

 

[Filip]

But what about the power loss, any idea what can be the cause of that?
Only happen when coolant sensor is connected.

MAF Sensor replaced
EGR cleaned
Fuel filter replaced
Coolant sensor replaced

Is relay 109 anyhow connected and can be the issue?

 

[Connorg115]

Clears faults on vcds

Take for test drive and then see what faults come back up

 

[Filip]

I've written in the first post:


If coolant sensor is disconnected: (no power loss)

2 Faults Found:
18062 - Please check DTC Memory of Instrument Cluster
P1654 - 35-10 - - - Intermittent
17664 - Engine Coolant Temp Sensor (G62): Open or Short to Plus
P1256 - 35-10 - - - Intermittent


If coolant sensor is connected: (power loss)

2 Faults Found:
18062 - Please check DTC Memory of Instrument Cluster
P1654 - 35-10 - - - Intermittent
17945 - Fuel Shutoff Solenoid (N109): Malfunction
P1537 - 35-00 - -

 

[Connorg115]

http://wiki.ross-tech.com/wiki/index.php/01237

I found this on the Ross tech website

 

[Filip]

Possible Solutions
Check/Replace Fuel Shut-Off Valve (N109)

Do you know on which position this part is located (Fuel Shut-Off Valve)?
I can't really find it on google for Seat Leon.

 

[Connorg115]

I’m not very familiar with Diesel engines sorry, however if you know your engine code that may help locating information as usually there are many cars with the same engine