Saturday, November 21, 2015



Gone are the days when you could fix your own car with simply logic. Today you require digital logic, a scan tool  and a tech savvy mechanic to make sense of the latest cars because they are all very precisely controlled by electronic circuits. The Engine Control Module is just one such circuit and largely depends on several of its sub-circuits to achieve the precision needed to propel the latest engines using high octane fuel, and burn it stoichiometrically in order to deliver the performance expected from these modern cars. But this is easier said than done because these sub-circuits rely on a number of inputs sensors and actuators distributed all over the engine and the car in general, to successfully control of the crank synchronous path.

In order for the ignition sub-system to function optimally for example, it requires feedback information about what is presently happening in the engine so that it can take corrective action if needs be, in real time. Likewise the fuel mixture sub-circuit can only determine if the mixture is rich or lean form feedback information, then take corrective action to increase or decrease the quantity of fuel based on the amount of oxygen present. Like wise the crankshaft timing sub-circuit depends on feedback information and maintain a constant torque. Yet all three these ECM sub-circuits works very closely in conjunction with one another and other sub-circuits to achieve optimal performance. 

Restated, the ECM is in control of the torque and torque reduction circuits, which just happens to annoy the arse mousse out of Volkswagen, Audi, SEAT and Skoda owners. It is commonly referred to as the EPC -Electronic Power Control. Essentially EPC is limp modes best friend and vehicle owners worst eneny.  ECM torque reduction is handled via the crank synchronous path, and involve the  ignition system sensors, the knock sensors, and fuel mixture both short trim and long trim. 

Input signals are needed for calculating precise ignition timing:

1) Engine Coolant Temperature Sensor (ECT)  

2) Engine Speed Sensor (RPM)  

3) Throttle Control Valve Sensor  

4) Camshaft Position Sensors

5) Knock Sensors  

6) Accelerator pedal Position sensors

By monitoring the Engine Coolant Temperature Sensor (ECT), the ECM varies the parameters of the engine as it heats up and maintains it when it has reached the correct operating temperature. By monitoring Engine Speed Sensor (RPM) the ECM can determine how many times the coils misfires per 1000 revolutions and how many times the injectors fail to deliver fuel. By monitoring the Throttle Control Valve Sensor the ECM can calculate the torque compared to how wide the throttle opens. By monitoring the Camshaft Position Sensors the ECM can better determine the exact time when the valves close and the exact point of ignition. By monitoring the  Knock sensors the ECM decides whether detonation is bad enough to take action, either the engine to rev or turn it reduced the torque and consequently prevent engine damage. By monitoring the Accelerator Pedal Position sensors it can determine synchronicity between the position of the accelerator pedal when depressed and the throttle control valve and and discrepancy outside of its normal parameters will reduce the torque. 


Knock sensors are very important to the overall engine torque because they detect combustion knocks in the individual cylinders. This is common when high octane fuel self ignites  which is generally known as knocking (detonation) or pinging (pre-ignition).
Knock sensors are piezo-electric components and acts something like  microphones do, but instead of picking up sound,  they detect vibrations in an engine which are needed by the ECM to correct the combustion process in the event of detonation or pinging.  This allows the ECM  to "retard" the engine so that it would work with different quality fuel. This implies that lower octane fuels are more prone to knock.


Four and six cylinder engines have 2 knock sensors each. Knock sensor 1 monitors the even bank of cylinders while Knock sensor 2 monitors  the odd bank of cylinders. W8 and W12 engine have 4 knock sensors each.  Knock sensor 1 monitors  cylinders  1 & 2, Knock sensor 2 monitors  cylinders 3 & 4, Knock sensor 3 monitors cylinder 5 & 6, and  Knock Sensor 4 monitors cylinder  7 & 8. Knock sensors are mounted directly on the crankcase and must be torqued. Failure to torque a knock sensor may cause it to malfunction and pickup engine vibrations as well as detonations.

The plug for Knock sensor (KS) 1 is normally green and it monitors cylinders  1 & 2, whereas the plug for Knock sensor (KS) 2 is normally grey and it monitors cylinders 3 & 4. Knock sensors are three pin devices with  Pin 1 = Signal, Pin 2 = Ground and Pin 3 = Shielding. Using a multimeter measure the resistance for "short circuit" between pins 1 and 2, then 1 and 3, then 2 and 3 at the Knock sensor connector. This measurements should always read infinity (open circuit).  If short circuit, replace knock sensor and make sure that it is correctly torqued to the crankcase.  Also check the wires for short circuit. If short circuit, replace. If a oscilloscope is available, connect it between pins 1 & 2 of the knock sensor. Tap the knock sensor lightly with a wrench, this should produce a fairly high frequency irregular sinusoidal waveform with a higher amplitude towards its middle. If there is no waveform coming out of the knock sensor its best to replace it because it will lead to a rise in fuel consumption and the engine management system may reverts to emergency knock control and reduce overall engine performance.

Thursday, November 19, 2015



By now, virtually everyone who owns a VW, Audi, Skoda or a Seat or any other vehicle and even those who don't, must  have heard about the Volkswagen AG emissions scandal. A scandal of global proportions  that rocked the entire automotive  industry and affects 11 million diesel powered vehicles as well as some 430 000 petrol powered vehicles, all of which were fitted with the now notorious "cheat device". Initially the Volkswagen management pleaded ignorance about said "cheat device" but later stepped up to the plate, admitting their liability and offering to make restitution to all VAG vehicle owners directly affected  by the "cheat device"

This excludes you and me and all our fellow VW group vehicle owners who have also been compromised by Volkswagen's exploits, whether it was intentional or not. I'm specifically referring to all VAG vehicle owners loosing value on the vehicles since the scandal  broke, which is still dropping steadily.  According to Volkswagen we would just have to bite the bullet, but is offering to make a once off financial cash/voucher disbursement to all VAG vehicle owners directly affected by the "cheat device". Meanwhile, Governments from several countries are up in arms about their carbon credits, and instituting litigation against Volkswagen for the shortfall on taxation paid by consumers, because of the "doctored emission values.  Scandal mongers have been heckling and spreading rumours that the emissions problem, more than likely affect all of the 127 models of cars produced by Volkswagen. 

However, in my opinion, Volkswagen cannot be the only auto manufacturer that got their emissions figures to wrong, especially considering its global market share and its clout within the automotive industry. It gives the impression that someone out there is not too happy with Volkswagen for whatever reason and decided to set the wheels of blame, revenge, envy in motion. Having said that, there are rumours and allegations that other motor manufacturers used similar software  devices to cheat at emissions. However, none of them have come forward or owned up like Volkswagen did. Is it possible that the Kyoto protocol emission reduction agreements that were discussed over several years then ratified are unattainable, too presumptuous or just impossible to meet? If there is even the slightest truth in that, then all automotive manufactures would fall short of the target. Or is it that out of a class of x, Volkswagen is the only kid that failed. 

Evidently his cannot be true especially considering that German engineering impress and in many cases even exceeds their own expectations.  Based on this assumption, I call for emissions testing across the entire spectrum of motor vehicles, especially American cars because they were renown as gas guzzlers and where there is fire, is obviously a lot of smoke. With COP21 just a month away, it would be in the interest of all vehicle owners to demand that their preferred manufacture submit their cars for emission testing. It would be a great injustice to Volkswagen and VAG vehicle owners if all the manufacturers are guilty and only Volkswagen gets burnt in the process. Add you opinion below if you think that all motor manufacturers emissions figures needs to be scrutenized.

Monday, November 16, 2015



Believe it or not, I got locked inside my VW Polo and couldn't get out. The self lock was activated, and me pulling at the door release lever just had no effect. The locking indicator pin surfaced from hiding put retracted when I released the door lever. For the sake of clarity, let me start at the beginning.  In a previous blog, I mentioned that when my VW Polo 2.0 Highline sedan was returned from its 90 000 Km service, it came back with a stripped nut  that lightens the earth terminal of the battery. I suspected that it was the cause of intermittent loss of power steering and I was going to get round to replacing it, but I just didn't have the time. Yep, procrastination is an evil that does get the better of all of us at one time or the other. 

Anyway, getting locked inside my VW Polo on Saturday morning gave me a scare that I immediately went and replace the entire terminal and not just the stripped nut. The previous evening, whilst driving home from movies, the dashboard lights on my VW Polo stopped working, it kinda just went dark. So when I got home, I started fiddling to determine why, and I discovered that the wipers and the indicators weren't working either. Must be a fuse I thought.  So I went straight to the fuse box and whipped out  the scorecard. Seconds later I identified the fuse responsible for supplying the dashboard with power (marked with yellow arrow and see the powdery substance in fuse holder, it's most probably oxidation from condensation). I got out my multimeter and checked the 5A fuse (fuse 30) and as I suspected, it was open circuit, fused, blown. Oh crap, I didn't have a spare so the following morning, off I went to the auto spare to get a replacement.  It was rather hot so I opened my window about 10 cm before I took off. As I pulled away,  the  self  lock  engaged at the very moment I realized that I didn't  take my wallet. So I stopped, reversed back about the 100 meters I drove, switched off the engine pulled out the key, pulled the door handle and it wouldn’t  open. Pulling at the door release lever just raised the locking indicator pin put retracted when I released the door lever. I then reinserted the key, turned on the ignition, pressed the unlock button on the door, heard the door unlock, opened the door, jumped out, ran inside grabbed my wallet, got back into the Polo and off I went once again.  

This time, I noticed that the auto lock engaged at about 40km ph. Thinking nothing of it, I arrived at the auto spares, switched off the engine, pulled out the key, pulled the door release lever and like before it wouldn't open.  And as before I reinserted the key turned on the ignition, pressed the door release yet nothing happened. I then realized that the ignition wasn’t on. So I attempted to start the engine and nothing happened. The battery terminal wasn't making contact, I came loose once again and the engine wouldn't start. By extension, there was also no power to the door electronics that operated the door. In desperation to get out, I even tried the fob remote unlock button even though I knew that without a battery connection the door electronics cannot open and neither power the motor that rolls down the electric windows. I was stuck inside. I figured if I could get my arm through the 10 cm opening, I could possibly open the door manually with the key. But the opening was too small and my arm to thick.  Now it was starting to get hot inside the Polo. My only other option was to ask a passer-by to unlock the door for me. So a few minutes later an elderly gentleman walked by, whom I alerted, and speaking through the window opening, and handing him the key   through the window opening, I asked him to unlock the door which he obligingly did.  

With the door open, my mind was racing, what if the window wasn't slightly open, meaning I wouldn't have been able to pass the key to anyone to open the door. I would have been trapped inside and helpless. The escalating heat would have got the better of me. I probably would have had to kick-in the driver-door window since it's the only door that actually has a key receptacle, so that I could unlock it from the outside. This made me wonder what would happen if the battery gets damaged or destroyed in a collision and I was injured inside and not able to break the window. I know that in the event of a crash when the airbags pop, the on-board software is configured to automatically unlock the doors, but what if the supply voltage to the indicators gets shorted in a crash causing that fuse in question  also to blow. Clearly this is a hazard, and I would think a small sealed backup battery like those used for alarm systems fitted inside the cockpit under the dash or the consol would be a good idea. I think the brave among you should try to replicate this problem on your vehicles by removing the 5A fuse in question and disconnect the battery then assess whether or not this is acceptable design or a reason to get into Volkswagen's face about it. They are already going through the pressures of their emissions scandal, and it really isn't nice to kick a dog when it's down.

Friday, November 13, 2015



In a previous blog Audi Oil Pump Problem - Audi A4 Engine Noise, I mentioned the benefits of using VW 503.00 Long Life Engine Oil, but it seems that I was also mislead by the VW propriety oil specification the expanse of which I was unaware. This is probably the reason why my sister's A4 2.0L 2007 engine gave up the ghost. But as they say in the legal circles, "Ignorance of the Law is no excuse". Apparently as long ago as the year 2000 increased requirements compelled vehicle manufacturers globally to reduce exhaust emissions, minimize their carbon footprint, and improve overall fuel economy. Since motor oil plays a crucial  role in meeting these requirements,  the API's (American Petroleum Institute) old petroleum-based motor oils standards was abandoned by VW in favour of advanced cutting-edge synthetic motor oil formulations. As a result, the technologically advanced Audi engine designs required a very specific motor oil that met with Audi quality specification. 

Its newer models fitted with advanced fuel injection systems needs to  be lubricated  by this very specific motor oil formulations in order to guarantee optimal system reliability and fuel economy. These oil specifications started with VW 500.00 for models prior to year 2000 which has been superceded by VW 502.00. Then there is  also  VW 503.00, VW 503.01, VW 504.00, VW 505.00, VW 505.01, VW 506.00, VW 506.01, VW 507.00, etc, each applicable to either or both gasoline and diesel Euro standard engines. But certain oil specs are not suitable for certain vehicles. For example RAVENOL WIV III SAE 5W-30 is not suitable for specification VW 506 01. Meaning Audi engines with LongLife Service (QG1): Diesel-Engines (R5-, V10 TDI Pumpe-Düse) with or without Diesel Particulate Filter.  As well as  Audi engines without LongLife Service: R5-, V10 TDI Pumpe-Düse with or without Diesel Particulate Filter.

Topping up with conventional motor oil that does not meet Audi oil quality standards is therefore risky because the wrong motor oils could cause damage to internal engine components, somewhat increase emissions, reduce fuel mileage, and very likely void applicable vehicle warranties. The vehicle is also bound to use excessive oil and tend to smoke a lot more.

Ravenol HPS 5W-30 oil meets the Audi oil quality standard 502 00 and is  recommended for Audi A4 2005/2006 and on Audi A3 models equipped with the 2.0 Liter Turbo engine with FSI. Their fuel pumps are driven directly off the engine camshaft and lubricated with engine motor oil.  By not using the approved Audi motor oil  these models are subject to premature engine wear which will result in a loud ticking valve noise  after the engine has warmed up to its  operating temperature.  

Ravenol VMP Audi Oil 2010 - meets the Audi 507 00 Oil Spec and is recommended for use on Audi A3 TDI and 2009 - on Audi Q7 TDI models equipped with a Diesel Particulate Filter (DPF). Using non-approved Audi motor oil will results in increased oil consumption oil since it will be burning oil. Any non-approved TDI motor oils will clog the DPF  prematurely which is also  quite costly to replace. 

Since the VW oil specification and oil usage cannot be generalized across the Audi and Porsche ranges and old petroleum-based motor oils are no longer usable, it is no wonder that Audi owners are complaining about excessive oil use. Some Audi owners have driven as little as 600 miles or about 950 kilometers before the engine oil low light goes on and the buzzer drives  the m crazy. This is probably because they topped-up with non synthetic oil. Funny enough, Audi stresses the  point of not adding petroleum-based motor oil to its synthetic brands.

Sunday, November 8, 2015



Thus far Volkswagen AG, Audi AG and Volkswagen Group of America, Inc. and Volkswagen (VW) as a whole has gone through the mill for the EPA emissions scandal that broke on the 18 September 2015. They have suffered massive third-quarter financial losses. Legal injunctions have compelled them to recall 11 million vehicles fitted with the now notorious 2.0L TDI engine. They are obliged to repair them entirely at their own cost which could take at least two years. They had to set aside some 7 billion Euros as restitution and compensation to VAG vehicles owners whose vehicles will, as a result of the "cheat device", have  diminished performance and poorer fuel economy. They fired their heads of Research and Development and launched an internal investigation into the “rogue software engineers” responsible for fitment of "cheat device". They have even instated a new CEO, Matthias Mueller, the former  boss of Porsche to the helm, to steer them out of the arse mousse  that Volkswagen find themselves sinking into deeper day by day.

The largest Automobile manufacturer in the World.
As if this isn't enough,  US’s Environmental Protection Agency (EPA) just notified Volkswagen Aktiengesellschaft of a second breach of clean air legislation. On the 2nd  November 2015, the EPA issued them with a second notice of violation (NOV) of the Clean Air Act. This NOV alleges that VW developed and installed defeat mechanisms in model years 2014 through 2016 VW, Audi and Porsche light duty diesel vehicles equipped with 3.0 liter V6 TDI engines. The harmful nitrogen oxide (NOx) emissions produced by diesel engines fitted in the 2014 VW Touareg, the 2015 Porsche Cayenne, and the 2016 Audi A6 Quattro, A7 Quattro, A8, A8L, and Q5, appear to exceed the EPA’s standard by at least nine times. 

3.0 Liter V6 TDI Engine
In their own defence VW emphatically denied the charges of fitting the “cheat device” into its luxury brand of vehicles. However the following day  VW admitted that certain “unexplained inconsistencies” had been found during the testing process for CO2 emissions. VW added that approximately 800,000 vehicles are currently thought to be involved, most of them sold in Europe.  But some of the vehicles now involved have petrol engines, implying that the scale of the second  installment of the emission scandal could be much greater than initially assumed. 

Suddenly the credibility of the “rogue software engineersargument just fades into obscurity. It is just to outlandish, flimsy and too incredulous now that Porsche and other luxury brand of vehicles are also involved. This boils down to down-right systematic manipulation and rigging of emissions test data by VW in order to gain themselves and unfair and an illegal  competitive advantage over its competitors. These latest developments just tarnished Volkswagen’s reputation and future sales even further, perhaps irreparably.  But to regain any sort of confidence and trust from both customers and investors, Volkswagen would have to make some radical changes to its management  and come clean. 

Considering that for the first time Toyota sales has overtaken that of VW.  And that Volkswagen  will forfeit all its CAFE (Corporate Average Fuel Economy)  carbon credits, and have to pay the taxation difference between the lower vehicle tax that  VW’s customers have unwittingly paid and what was actually due. Besides  getting grilled at COP 21 on the 7- 8 December 2015 for fooling the rest of the world twice.  And to add insult to injury, VW sales across all models, including petrol engines sales dropped by almost 10% since October 2015. Credit ratings agencies Moody’s and S&P have downgraded VW and three other major ratings agencies have VW on negative watch considering further downgrades. What a  deal breaker!

Sunday, October 25, 2015



For the past week my sister's Audi A4 2.0L 2007 has been having issues. When it starts its engine sounds like a tractor engine but after about 15 secs it quietens down and sounds and idles perfectly normal. Ever since its engine oil and oil filter change some seven weeks ago by her friend. The "Engine oil pressure light" keeps turning on, after some 20 minutes of driving, accompanied by a beep from the pizzo electric buzzer. Thereafter  it repeatedly  triggers  unexpectedly,  actually giving her a fright every time it does. I ran a scan with VCDS and there was absolutely no sign of engine trouble or DTC from the engine. Except for ABS signal out of specification fault which is totally unrelated to oil pressure. So since there was no problem other than the engine  Engine oil pressure light that triggered daily she decided to drive the Audi in that condition and tolerate the beeping. 

I inquired about the oil that they used, thinking perhaps that if the  grade of oil was too thick, it would affect the oil flow and pressure.  She fetched the container which still had some oil in it from the garage to show me what it was and on inspecting the viscosity of the oil between my thumb and forefinger I was amazed by the crap they sell unsuspecting customers. It turned out that she bought SAE 10W/20 oil at the local supermarket off the automotive shelf because it was going cheap. The oil was so thin, it was virtually like water, it couldn't even form a drop at the end of my finger. I even asked her if they mixed paraffin with the oil and she said no. I looked at the writing on the container to see if it wasn't two stoke oil for lawnmowers but it wasn't. 

Audi A4 Oil Pump (Old Top - New Bottom)
I then knew that this was the cause of the problem. The oil was too thin and the oil pump had difficulty in getting enough oil to the cams, bushes and gears  resulting in the noise caused by excessive friction during the the first 15 seconds when started. I actually thought that the oil may be too thick, so that the  oil pump couldn't push through the required volume of oil per minute. After telling her what an idiot she was to buy this cheap crap oil, I begged her to get some VW 50300 Long Life Engine Oil from the Audi agents.  I even offered to drain the crap oil out her Audi, flush the engine, replace the oil filter and fill it with the correct oil. The VW 50300 Long Life Engine Oil does cost a lot more than regular oil put it has the advantage of 30000 km before the next change. Fortunately it costs less than VW Automatic Transmission Fluid

So after replacing the filter and filling up with the new oil, the Audi now sounds a lot better but it is still noisy. Not as loud as it was before and the duration of the noise reduced from 15 seconds to about 4 seconds. Its  going to cost her a new oil pump replacement within the next week or so, because driving with a suspect oil pump is asking for the engine to seize and heaven alone knows what that's going to cost to repair.

Monday, October 12, 2015



Its been four months since the accident that triggered both my VW Polo's airbags. Even though damage to the body was slight, my polo has been standing for all this time while repairs were effected. Now that everything is fixed and ready to take the Polo on the road once again, there appeared to be a huge problem. I couldn't select any gears whilst the engine idles because it grinds horribly but was able to select them when the engine is off. I have even selected a gear then turned the ignition, just to see it the clutch and pressure plate engages. After several attempts at grinding every gear, I came to the conclusion it may not be the gearbox that's at fault but perhaps the clutch that is not disengaging from the flywheel sufficiently.  So I started the engine and pumped the clutch for a several minutes. Thereafter it started selecting gears with difficulty and after several attempts it was back to normal. I took the Polo on the road and every thing was just great. 

02E  Automatic Transmission EPC Solenoid DSG  Gearbox  valve body   (Electronic Pressure Control) solenoid 

This so reminds of my friend Aron who also had or rather is still having a nasty transmission problems with his Jetta.  When he selects a gear, there is  loud thud coming from the transmission, then the  P, N, R, 1, 2, 3 light in the  instrument cluster flash red for a while then just stays on. In fact the light display is reversed, solid red back ground with whiteout text.  His car is fitted with DSG transmission. Direct-Shift Gearbox (DSG), Multitronic DSG / CVT Transmission  repairs can be and are invariably quite expensive and this problem looked and sounded very expensive. So to save money, he decided to repair it himself.  After watching what he had to do, I realized that a bad transmission is definitely not a DIY project, unless you have the mechanical and electronic expertise and the necessary specialized equipment. 

A 02E transmission scan came up with the following data:- 

 Address 02: Auto Trans Labels: 09G-927-750.LBL
Control Module Part Number: 09G 927 750 HJ HW: 09G 927 750 CJ
Component and/or Version: AQ 250 6F 1068
Software Coding: 0000072
Work Shop Code: WSC 31414 000 00000
4 Faults Found:

17104 - Transmission Output Speed Sensor (G195): Circuit Malfunction
P0720 - 012 - Electrical Fault in Circuit - MIL ON
Freeze Frame:
Fault Status: 10101100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 44
Mileage: 104552 km
Time Indication: 0
Date: 2010.10.19
Time: 16:39:08

17099 - Transmission Input Speed Sensor (G182): Circuit Malfunction
P0715 - 012 - Electrical Fault in Circuit - MIL ON
Freeze Frame:
Fault Status: 10101100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 39
Mileage: 41353 km
Time Indication: 0
Date: 2015.08.08
Time: 00:00:00

17094 - Transmission Fluid Temp.Sensor (G93), Circuit Malfunction
P0710 - 010 - Open or Short to Plus - Intermittent
Freeze Frame:
Fault Status: 00101010
Fault Priority: 2
Fault Frequency: 1
Reset counter: 184
Mileage: 41353 km
Time Indication: 0
Date: 2015.08.08
Time: 00:00:00

01680 - ABS Wheel Speed Signal; Front Right
013 - Check DTC Memory
Freeze Frame:
 Fault Status: 00101101
Fault Priority: 2
 Fault Frequency: 7
Reset counter: 201
Mileage: 41353 km
Time Indication: 0
Date: 2015.08.08
Time: 00:00:00

The transmission gets  a speed signal from the front right side wheel which is needed by the TCM to determine the speed of the car and when it should change gears hence there is an ABS fault listed above. After stripping the valve body, he found that the transmission oil looked like there was water in it, a sort of milky grey instead of reddish translucent. It turned out that the previous owner never bothered to replace the transmission oil at all. There were iron fillings attached to the magnets in the sump and some black plastic bits from the solenoid plugs could be seen in the oil, liquidized by the gears.  This most likely caused solenoid EPC (electronic pressure control) solenoid to seize, preventing it from moving when pulsed because it caked-up around the plunger.  In fact the entire loom was so brittle when  it was unplugged that it just disintegrated into crumbs.  Considering that the engine is attached to the transmission, both of which produce tremendous heat which virtually "cooks" the transmission oil at 40 degrees C. Its no wonder the transmission harness  is overcooked hard and brittle because it lies in this hot oil. It's also very surprising that VAG cars with DSG transmissions aren't more trouble some than they already are, because the electronic mechatronic unit sits inside the gearbox. As bad luck would have it, Aron's Jetta's mechatronic device was fried and needed to be replaced along with the internal harness.  No electronic component other than "military spec electronic components" was designed to withstand of survive such huge amount of heat.  

Anyway, the EPC (Electronic Pressure Control) solenoid was replaced after the valve body tunnels was cleaned with a rifle cleaning wire brush and reassembled. Two more rubber seals on two other solenoids were also replaced and as mentioned earlier, the mechatronic unit and the internal harness.