VW Jetta – Check Engine Light (18613 / P2181)- Thermostat Issue

The CEL light recently came on while I was driving so I scanned the code with a scanner.
The code came out to be “18613 / P2181- Performance Malfunction in Cooling System”

Screen Shot 2014-10-04 at 3.40.34 PM

I ignored this issue for a few weeks and noticed the CEL light went away for a time but as soon as the outdoor temperatures dropped down the light would come back on.

The issue was the thermostat in this case, especially considering that when the outdoor temperature changed, the light would come back on.

To fix this issue, simply replace your thermostat.

The procedure is not too complicated. Simply drain the coolant and remove the thermostat. The hardest part is removing the bottom bolt on the coolant outlet connection.

Normally I’d post a more in depth guide but I found a nice video on YouTube that will show you exactly what to do:

Leaking Exhaust Fumes into Cabin – Broken Flex Pipe (MK4 Jetta)

I’ve been driving for about a year now with an exhaust leak in my cabin which was quite annoying during the winter months.
Basically exhaust fumes were leaking from a cracked flex pipe and would creep up under my hood and then into my cabin.

Symptoms of a broken flex pipe (or a hole anywhere along the exhaust) are leaking fume smells around the cabin as well as little to no pressure build up
when you cover the tail pipe. In fact you’ll probably hear the fumes escaping through the crack if you block the tail pipe.

Note: My vehicle is a 2.0L gas engine (BEV engine code). The Diesel variants have a different size flex pipe so make sure to measure it before buying/installing another one.

This is a relatively big job… But will save you about $1200 (without labor) because the flex pipe is sold together with the catalytic conventor.

A word of caution.. This involves grinding out and smoothing the catalytic convertor and this is a one of the harder jobs to do due to rusted bolts, limited space etc.
Then you have to weld the new flex pipe to the cat and the pipe piece that goes into the exhaust manifold.

The OEM VW flex pipe is not sold separately as it is already welded to the catalytic conventor. If you want to fix the flex pipe without any work you have to buy a whole new catalytic conventor! To save yourself a hefty sum, you can buy an after market flex pipe and install it where the old one was.

If the leak you experience is indeed from the flex pipe, then follow below:

To start, first locate the flex pipe. Lift up the car and you should see it as seen in the photo below (Click the images to get a full resolution image):


I pulled back the protective shield to get to the leak and found the crack as shown below:

I then cut out the old flex pipe so that I could get a rough measurement of how big it was. Once you cut it out there is no turning back!
My flex pipe measured to be around 10 inches long with a diameter of 2 inches. Be sure to measure how long your flex pipe is.
I went out and bought a comparable generic flex pipe from our local parts store. It cost me $60 for a brand new flex pipe.
Make sure the flex pipe you buy is stainless steel

Next, remove the entire catalytic conventor from under the car by loosening the clamp bolts that hold the resonator and catalytic conventor pipes together.
With a bit of wiggling and turning the catalytic conventor should slide right out of the clamp. Don’t forget to disconnect the oxygen sensor that is connected to the cat.

Handle it with care as well since an O2 sensor is quite pricey.
Be careful with the cat! It is still perfectly fine and we do not want to damage it. Handle with care!

Grind the end piece off that was originally from the broken flex pipe. You will have to do this with the pipe that also connects to the exhaust manifold as well.
Getting the pipe off of the exhaust manifold was hard because the bolts were rusted out and would not come out without a fight.

When grinding make sure to only grind off the piece that was part of the flex pipe. Do not damage the pipe underneath the welding! See image below too see what must be grinded off.

After removing the cat and grinding the ends down to only have the pipe, the new flex pipe was welded on. Unless you know how to weld or even have a welder available. I’d suggest taking it to a shop that can do this for you. Be sure to get a stainless steel flex pipe as an generic metal one might not weld as well and will rust faster.

The following are images of my finished result. I used a TIG welder to connect the flex pipe:

With the new flex pipe welded on, the entire catalytic conventor assembly can be put back in place… but first I recommend you check one thing; the holder for the resonator pipe.

I am unsure of the correct term for this piece so I will refer to it as the “holder”. This is what a typical holder should look like:

This is what mine looked like:

My holder was completely rusted out! There was nothing holding the pipe in place to absorb vibrations. I took the old rusted holder and welded a square piece of stainless steel with two holes through it so that a 50mm clamp could fit through. I then put the clamp around the pipe and through the square piece and fastened it together with new bolts as the old ones were rusted out. I am hoping this self made holder lasts me for a while. I had to make my own holder because again, VW decided to make it part of the resonator assembly so if you want an OEM holder you are going to have to buy a new resonator.

This missing holder could be the reason for the flex pipe cracking because the stress from the entire pipe twisting and bouncing could have, over time, destroyed my flex pipe.
Be sure to check the holder piece on your car even if you do not have issues.. it may save you a lot of time and money in the future!

I do not know how much a new resonator would cost from the dealer but I can assure you that it wouldn’t be cheap. By making my own holder I saved myself another huge sum of money.

All in all the new flex pipe has been working fine so far. My total cost to do this was under $80 including the flex pipe and making a new holder. I easily saved myself about $2000 with labor since I would have had to replace both the catalytic conventor and the resonator. The job was certainly worth it but it was a bit of a headache to do. With a bit of (a lot of actually) elbow grease and sweat, you too can accomplish this and save yourself a lot of money.


Micro Inverter Project Completed

After a hectic few months, the micro inverter is now fully working with decent results.

I used a 3 KHz low-pass filter mainly because of cost but the sine wave still turned out to be quite good. The inverter delivers between 115-120V (RMS) and
can handle up to 3 Amps all while delivering a 60 Hz sine wave.

It’s a decent outcome for a first time project but there is still room for improvement such as making it more compact.

Inverter Protoype

Capstone Update – Sine wave Inverter

The first milestone of my final capstone project involves making an inverter from scratch. The inverter also has to output a relatively clean 60Hz sine wave.

The inverter is to be supplied from a solar panel. For my small scale prototype so far I only used a 9V battery + the Arduino 5V supply since it is convenient to work with.

My inverter consists of an H-Bridge which is basically four MOSFETs that switch on in pairs. The circuit I made is very bare bone but gives a decent sine wave.I used an Arduino Uno to do Pulse Width Modulation(PWM) to switch the MOSFETs and then filtered the output.

As seen, the sine wave was relatively decent for this type of set-up. Putting in a better filtering system and some pull-down resistors, etc would yield an even better result. Also creating an actual PCB over a “spaghetti circuit” would help with noise as well.

Also you might notice the oscilloscope I’m using is a portable handheld one. It has a good resolution and is good for my application as I am not working with high switching frequencies (greater than 1Mhz). It’s an ARM Nano DSO201 if you’re wondering and is not expensive.

Below are some snapshots of my prototype:
Inverter circuit

Inverter output

Ontario Releases Updated Long-term Energy Plan

Ontario recently released its long term energy plan. It can be viewed at the following link:

Ontario looks to move toward “green energy”. It also talks about the refurbishment of the Bruce and Darlington nuclear plant refurbishment, set to start in 2016. The Pickering nuclear plant is scheduled to be shut down in 2020.

Capstone Project

wind-turbines-connected-to-gridMy Winter 2014 Capstone project is titled “Integration of Alternate Sources of Generation into the Grid”

More details to follow as semester progresses.

Adobe Password leak- Are you affected?


Recently there was a leaked database containing about 150 million users passwords. If you were affected, it is highly recommended you change all your passwords for every website. To check if you are affected enter your email below:

Flashing Check Engine Light & Coil Pack (MK4 Jetta)

In Spring 2013 I was driving to the gym and all of a sudden my Check Engine light (CEL) began to flash (orange color). My car began to stutter and vibrate unnaturally. Immediately I pulled over and turned off the car.  I waited about 1 minute and turned the car back on– the CEL was still flashing yellow and the car was stuttering. I decided to go to the gym and come back after an hour to try and turn it on again. When I came back the car was no longer stuttering! But the CEL light remained on (wasn’t flashing though). I took the car back home in Toronto and drove it for a week without issues. The car would stutter a bit only on start-up but would go away once the engine temperature rose.

I noticed the problem with the flashing CEL / engine stuttering would usually only come up on a cold engine and when it was moist outside (after rainfall or light snowfall in the spring).

After a week I drove back home to Windsor (about a 250 mile /400km drive) without issues.

When I got home the first thing I did was scan my car. I was getting codes for Cylinder #2 misfiring and short to ground codes for the cylinders.
Upon some investigation and research it turned out to be the Coil Pack. Physically, the coil pack from the outside looked fine, but upon closer inspection I noticed fine hairline cracks (very small). I found the majority of the cracks around the 2nd input for the ignition cable, which also matched up with the Cylinder #2 misfire. The were some other cracks around other ignition lead inputs as well.

Cracked Coil

My first attempt at fixing this was covering the cracks with epoxy. This seemed to work but about a month later I was washing my radiator and engine bay and upon start up the car up the car started to stutter and the CEL was flashing. At this point I gave in and bought a new coil pack from AutoZone(~$260 USD).

These cracks were so small that you wouldn’t notice them unless you unscrewed the coil pack and took the unit out and examined it closely under light. The fine hairline cracks was all that was needed to create tiny electric sparks in the dark that caused it to short.Ever since replacing my coil pack and ignition cables my issue with the flashing CEL and stuttering has been resolved.

Parts needed (VW part numbers):

06A-905-409-N  –  IGNITION LEADS (Cables)

06A-905-097  – COIL PACK


Fuel pump relay & Check Engine Light (MK4 Jetta)

Recently my car has had issues starting sometimes and my Check Engine Light (CEL) has been on. Car starting issues can be quite stressful if they happen at the wrong places or time so I decided to note my experience with this issue.

The first step is to SCAN YOUR VEHICLE. I personally have my own scanner but you can scan it anywhere. The CEL by itself doesn’t mean anything to you until you diagnose the problem.

Once I scanned the vehicle, a list of codes came up for me:

If you examine the codes, you can see that they all have reference to ELECTRICAL related issues (short to ground, low voltage etc..). This lead me to believe that it is most likely some kind of wiring issue because it’s highly unlikely that all of those components failed simultaneously. I then took a look at the Bentley manual and found a diagram that showed the relationship between the ECU and other electrical components.

Looking at the diagram you notice that all those components were coming up on the scanner. Between the ECU and all the components (O2 sensor, Vacuum pump, etc..) I noticed that the fuel pump relay was interacting with everything.

ECM Relationships

ECM Relationships

The first thing I did was check the fuel pump relay. The fuel pump relay on this car gets primed every time you open the driver door. Sometimes I noticed it wasn’t priming and when this happened the car would not start or have a very rough start. The relay is located under the steering wheel. It has the number “409” written on the back of it. It is a small box with a width of about 1 inch. The fuel pump relay is almost like a plug. It has contacts that plug into an outlet making this quite an easy fix (you do not need to pay a mechanic for something as simple as this). Swap your old relay with a new one from the dealership.


My old relay was an OEM VW part and it had 8 PINS. The relays seem to have undergone a redesign and are now 7 PINS. I verified this with VW of America. You will see that pin #7 is missing in the newly redesigned relays.

I first bought the generic brand relay from Autozone and tried it(was a 7 PIN relay). The car would start fine BUT if you opened the driver door while the car was running it would SHUT OFF COMPLETELY. I’ve read reports that other generic brands like NAPA also have this issue. I’m not sure as to why because both the OEM and generic brand have the same circuit structure printout that you can see on the relay.

In short the new OEM relays are 7 PINS and they WILL WORK with your Jetta (MK4). The NON OEM relays that are 7 PINS WILL NOT WORK because as soon as you open the door while the car is running or you are driving your car will shut off!

Old 8 Pin Fuel pump relayIMG_0121

Once I swapped my old relay with an OEM relay the car started smooth as it should and the CEL was gone once I cleared it with the scanner.


Parts needed (VW part numbers):

1J0 906 383 C  –  Fuel Pump Relay


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