Friday, June 10, 2016

My Jetta TDI is gone

A hail storm in my region damaged the windshield, and dented all around the body of the Jetta. Usually this would not have happened if I put it into the garage. However, I was afraid of the pipe waste of the diesel engine and decided to leave it outside.

The Jetta TDI 2004 had a mileage of 17.5k and was still strong. Except for the cosmetic damages, everything else was excellent:

1, Replaced by self all four brake pads/rotors;

2, Replaced three of the wheel bearings and bearing housings (I have all the necessary tools to do this job);

3, Had timing belt/water pump/fuel filter replaced at 15k miles (close to $1000 by a Serbian mechanic);

4, Replaced the tires with Michelin tire at costco (>$500);

5, Replaced the thermometer;

6, Replaced the brake vacuum pipe with check valve;

All together more than $3000 was spent after took it in for $6750 in 2012 -- I drove it for 4 years. It seemed to cost $750/year for maintenance.

Not a good deal but it drove pretty fun -- like a little toy with very good agility.

Traded it in to a VW dealership for $1100 after repairing the windshield ($200).


Sunday, October 04, 2015

P0128 OBD-II Trouble Code of 2004 VW Jetta TDI

I always have the impression that usually diesel cars are not sensitive to throw out faulty codes until something is really going wrong. However, for the first time after owning it for two years, the yellow light is on with code P0128:  which means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The easiest part to replace is the coolant temperature sensor (CTS), which costs $55 bucks at the dealership along with the $5 O-ring. 

The original installed sensor is a black one and said to be easy to break. The improved part is green (see the above picture). To replace the sensor is not difficult but could be messy, since coolant will nevertheless run out during replacement. The CTS is located right below the vacuum pump at the diver's side of the engine bay. (See the second picture.)

The following is how the sensor sits in the car:

To access the sensor, it is recommended

Step 1: remove the intake hose and housing. 
Step 2: remove the electric connector; press the pin on the connector to release;
Step 3: insert a small flat head screwdriver below the sensor to release the clip which holds it.
Step 4: remove the old sensor along with the O-oring.
Note the O-ring may get stuck inside and cause trouble to install a new one.  Remember to search for it.

Note also that the connector may not be easy to release. In such a case, one may choose to reverse step 3 and step 2, allowing more room above the engine bay to remove the connector with the old CTS still on.

Step 5: Install the new CTS with new O-ring, and the new clip to hold them.

Step 6: Hook on the electrical connector.

Step 7: Add more coolant to the required level. Remember to recheck it after driving a few times.

Step 8: Remove the faulty code with a scanner. The code does not go away automatically.

Step 9: That is it.