Common problems + repairs
#1
03-28-2009, 03:27 PM
Common problems + repairs
So many times have i seen the same posts and many times have i seen the wrong diagnostic procedures were issued by members. Im making this sticky as a guideline for future diagnosis.
1. Overheating, when your gauge is telling you that the engine is overheating, your very first step is to verify that it is indeed overheating. Open the hood and check the coolant lines with your hand, look at the coolant resivior, overheating causes the coolant tank to boil over and lose coolant. Feel the radiator, if it feels cold the thermostat is stuck closed and needs to be replaced. If the radiator is warm (but not hot) but the hoses feel hot as hell going into the radiator you probably have a bad water pump. These both happen around the 60-80k mark. Replace the timing belt, water pump, thermostat etc. and you won't have any more problems.
2. CTS sensors, the black sensors are faulty, and will cause gauge malfunctions, increased fuel consumption, rich fault codes, excessive cranking times when the engine is warm or cold, and even random misfire faults. Replace with a green top sensor to cure these issues.
3. No start concerns. (cranking but no start) These generally don't have fault codes but that is the first thing you should check with your vag com or code reader. If you find a fault code for the engine crank sensor replace it. If you have a yellow flashing light in the cluster you have an immobilizer problem and the dealer has to fix this for you. If there are no fault codes open the hood and locate the fuel supply line. There is a 14 and 17mm nut next to each other, take the line loose and put the fuel line in an empty plastic water bottle. Turn the key to the on position. If no fuel goes into the bottle, check power at the fuel pump. If power at the pump is present with the key on replace the fuel pump. If no power is present, replace the fuel pump relay under the dash board.
4. No start concern. (won't turn over) No fault codes will be present for this issue, you commonly will have two problems here. A loose ground battery connection or a bad starter. Double check the ground connection, if thats good check power at the starter while someone else is cranking. If power is present replace the starter.
5. Humming noise upon start up. If you hear a humming noise upon start up that lasts for about 5-8 seconds, replace the fuel filter.
6. Torque conveter fault codes. Generally the first step here is to erase the fault codes and see if the fault comes back. You have no choice but to replace the converter, changing the fluid will not help you.
7. Cracking noises when operating the windows. This is the window regulator breaking, avoid using that particular window until the regulator is fixed.
8. No operation from the rear windows. If the switches for the rear windows don't work and the master switch also doesn't work, press down the window lock out button (in the center of the master switch) and have someone else push the buttons on the rear doors, if the windows magically move, you need a new master window switch.
9. No heat coming from the vents but the engine coolant temp is correct but the fluid is low. There is a TSB repair for this issue that requires replacing an O-ring under the intake manifold. Ask your dealer about the TSB and he will give you the correct repair parts.
10. Auxillary fan stays on after the key is shut off. This is generally caused by a faulty fan control module and it requires some major wiring work, if you are not mechanically inclined or know how to cutt and splice wires take the car to the dealer.
11. Auxillary fan comes on all the time the engine is on. There is a lot of things that the fan gets input from, the common problems are the two CTS sensors. Replace BOTH of them and double check concern. If this doesn't fix it, you cannot go any further and it has to be diagnosed at the dealer using a pin out box. A pin out box basically plugs into the ECM harness so the tech can trace power/resistance to each of the 300+ wires in the engine harness.
12. A/C blows hot air. This is another thing that really can't be diagnosed easilly by a person that isn't trained to deal with it. There is however a few things you can do.
You first of course check the fault codes using the vag com! See if there are any fault codes stored in the A/C control head. Another thing that is a dead giveaway is the ECON button is always lit and it won't change no matter what you do. This means the system is currently disabled for a failure, usually from leaking refrigerant. In which case you would need to diagnose where the leak is coming from by using a/c dye. A licenced professional should do this for you. You can fix it for a while by putting in some refrigerant yourself. (NOTE) Don't ask a part person for FREON!! FREON is R-12 and hasn't been used since the early 90's, so don't **** the parts guy off. You want want R-134a refrigerant.
13. Vibration issues. I'll make this very clear, vibrations can only be cause by a rotating componet. Example: Wheels, tires, brake rotors, or drive shafts. Replacing control arms for this is like pissing in the wind, you're not gonna get the result you want..
Your first step in diagnosing a vibration is to have the wheels spun on a balancer, if no problems can be found with the wheels, have the rotors measured for out of rounds. If either of these methods do not work put the car in the air, disable the ESP, and drive the vehicle up to about 60mph while someone else looks at all four wheels. If you see a specific wheel that is shaking more than normal, take that wheel off and install the spare tire and have the affected wheel replaced and or new tire. If two wheels are flopping out of control then you may have a propshaft problem (NOT LIKELY) Now if all FOUR wheels are wobbling and these are after market wheels, order hubcentric centering rings for all four wheels. Aftermarket wheels are drilled with a larger hub than stock audi wheels and need a spacer to fill in the gap to keep the wheel from wobbling.
14. Headlights flickering. If you are having headlamps that are flickering and have ZENON headlamps, swap the effected bulb to the other side. If the light still flickers on the affected side replace the ignitor/ballast on that side.
15. Trunk won't latch. This one should be easy but somehow people don't get it. The latch is electrical, this means if the latch doesn't want to hook on the striker the little electro mechanical part in the latch is malfunctioning. There is no diagnosis here, replace the latch. NOT THE STRIKER!!
16. CVT owners. If you own a CVT let me start by saying im sorry. There are several different TSB's out there for this trans that range from bucking, stalling, grinding, idle pop, slipping, reverse inop, and limp mode (all lights in dash light up red) First diagnose the TCM with the vag com, if you find a check sum error your TCM is toast and has to be replaced. The TCM is located inside the back of the trans on a CVT. If no fault codes are present replace the fluid. If this doesn't fix it you are either looking at a complete re-build with an updated 7plate clutch pack or a new trans.
17. 3.0L coolant leak. If you find that you are losing coolant but aren't overheating check behind the motor. If you see crusted dried up coolant, you are most likely leaking from a little nipple on the coolant cross over pipe. You will see a little 1/4 hose going straight into the pipe, the little nipple is what the hose connects to, replace the nipple and crush washer. Another cause could be the cross over pipe itself, which is a PITA to replace.
18. 1.8T coolant leak. Coolant leaks on the 1.8T are many, first check the obvious, coolant resivoir, radiator, CTS sensors. If those are ok look behind the motor, you will probably find coolant running behind the cylinder head and on to the trans, this is from a leaking coolant flange, you must replace the ENTIRE flange! Do not try replacing the O-ring, it won't work, trust me.
19. Power steering whine. If you hear whining from the power steering pump check the fluid. VW/Audi power steering fluid is a mineral based fluid that will evaporate over time. It has to be topped off every 15k, so keep some in stock in your garage. After adding fluid you have to aerate the fluid. To do this, leave the cap off the P.S. resivior, and turn the wheel lock to lock until the sound goes away.
Edit: Additions
20. Peeling or rubbing off of the button displays. Your fingernails are your worst enemy when it comes to plastic numbers/words being worn off, your fingernails are a hard substance and will natually rub off the softer plastic material. Its a more common complaint with women owners that have long nails. Basically can't do anything about this short of replacement of the button or switch.
If you see peeling or bubbling of the button/s this is another common problem, most people think its the sun that causes the issue. This isn't entirely untrue, but its more likely caused by cleaning products, soda, coffee, and the buttons are overall cheaply made. Try to keep any and all polishing compounds away from any of your electronic buttons/devices. Armor all is another compound that will attack the plastic.
21. Sunroof acting possessed. If you notice that your sunroof is acting like its being controlled by the devil, then chances are the switch (potentiometer) is dirty or faulty. What you should do first is take out the switch (above your head) and clean the contacts with some electrical contact cleaner, then give it a try. If it doesn't work the way it should just replace the switch, its not a very expensive part.
If i think of any more i will add to it, but seriously look these over.
1. Overheating, when your gauge is telling you that the engine is overheating, your very first step is to verify that it is indeed overheating. Open the hood and check the coolant lines with your hand, look at the coolant resivior, overheating causes the coolant tank to boil over and lose coolant. Feel the radiator, if it feels cold the thermostat is stuck closed and needs to be replaced. If the radiator is warm (but not hot) but the hoses feel hot as hell going into the radiator you probably have a bad water pump. These both happen around the 60-80k mark. Replace the timing belt, water pump, thermostat etc. and you won't have any more problems.
2. CTS sensors, the black sensors are faulty, and will cause gauge malfunctions, increased fuel consumption, rich fault codes, excessive cranking times when the engine is warm or cold, and even random misfire faults. Replace with a green top sensor to cure these issues.
3. No start concerns. (cranking but no start) These generally don't have fault codes but that is the first thing you should check with your vag com or code reader. If you find a fault code for the engine crank sensor replace it. If you have a yellow flashing light in the cluster you have an immobilizer problem and the dealer has to fix this for you. If there are no fault codes open the hood and locate the fuel supply line. There is a 14 and 17mm nut next to each other, take the line loose and put the fuel line in an empty plastic water bottle. Turn the key to the on position. If no fuel goes into the bottle, check power at the fuel pump. If power at the pump is present with the key on replace the fuel pump. If no power is present, replace the fuel pump relay under the dash board.
4. No start concern. (won't turn over) No fault codes will be present for this issue, you commonly will have two problems here. A loose ground battery connection or a bad starter. Double check the ground connection, if thats good check power at the starter while someone else is cranking. If power is present replace the starter.
5. Humming noise upon start up. If you hear a humming noise upon start up that lasts for about 5-8 seconds, replace the fuel filter.
6. Torque conveter fault codes. Generally the first step here is to erase the fault codes and see if the fault comes back. You have no choice but to replace the converter, changing the fluid will not help you.
7. Cracking noises when operating the windows. This is the window regulator breaking, avoid using that particular window until the regulator is fixed.
8. No operation from the rear windows. If the switches for the rear windows don't work and the master switch also doesn't work, press down the window lock out button (in the center of the master switch) and have someone else push the buttons on the rear doors, if the windows magically move, you need a new master window switch.
9. No heat coming from the vents but the engine coolant temp is correct but the fluid is low. There is a TSB repair for this issue that requires replacing an O-ring under the intake manifold. Ask your dealer about the TSB and he will give you the correct repair parts.
10. Auxillary fan stays on after the key is shut off. This is generally caused by a faulty fan control module and it requires some major wiring work, if you are not mechanically inclined or know how to cutt and splice wires take the car to the dealer.
11. Auxillary fan comes on all the time the engine is on. There is a lot of things that the fan gets input from, the common problems are the two CTS sensors. Replace BOTH of them and double check concern. If this doesn't fix it, you cannot go any further and it has to be diagnosed at the dealer using a pin out box. A pin out box basically plugs into the ECM harness so the tech can trace power/resistance to each of the 300+ wires in the engine harness.
12. A/C blows hot air. This is another thing that really can't be diagnosed easilly by a person that isn't trained to deal with it. There is however a few things you can do.
You first of course check the fault codes using the vag com! See if there are any fault codes stored in the A/C control head. Another thing that is a dead giveaway is the ECON button is always lit and it won't change no matter what you do. This means the system is currently disabled for a failure, usually from leaking refrigerant. In which case you would need to diagnose where the leak is coming from by using a/c dye. A licenced professional should do this for you. You can fix it for a while by putting in some refrigerant yourself. (NOTE) Don't ask a part person for FREON!! FREON is R-12 and hasn't been used since the early 90's, so don't **** the parts guy off. You want want R-134a refrigerant.
13. Vibration issues. I'll make this very clear, vibrations can only be cause by a rotating componet. Example: Wheels, tires, brake rotors, or drive shafts. Replacing control arms for this is like pissing in the wind, you're not gonna get the result you want..
Your first step in diagnosing a vibration is to have the wheels spun on a balancer, if no problems can be found with the wheels, have the rotors measured for out of rounds. If either of these methods do not work put the car in the air, disable the ESP, and drive the vehicle up to about 60mph while someone else looks at all four wheels. If you see a specific wheel that is shaking more than normal, take that wheel off and install the spare tire and have the affected wheel replaced and or new tire. If two wheels are flopping out of control then you may have a propshaft problem (NOT LIKELY) Now if all FOUR wheels are wobbling and these are after market wheels, order hubcentric centering rings for all four wheels. Aftermarket wheels are drilled with a larger hub than stock audi wheels and need a spacer to fill in the gap to keep the wheel from wobbling.
14. Headlights flickering. If you are having headlamps that are flickering and have ZENON headlamps, swap the effected bulb to the other side. If the light still flickers on the affected side replace the ignitor/ballast on that side.
15. Trunk won't latch. This one should be easy but somehow people don't get it. The latch is electrical, this means if the latch doesn't want to hook on the striker the little electro mechanical part in the latch is malfunctioning. There is no diagnosis here, replace the latch. NOT THE STRIKER!!
16. CVT owners. If you own a CVT let me start by saying im sorry. There are several different TSB's out there for this trans that range from bucking, stalling, grinding, idle pop, slipping, reverse inop, and limp mode (all lights in dash light up red) First diagnose the TCM with the vag com, if you find a check sum error your TCM is toast and has to be replaced. The TCM is located inside the back of the trans on a CVT. If no fault codes are present replace the fluid. If this doesn't fix it you are either looking at a complete re-build with an updated 7plate clutch pack or a new trans.
17. 3.0L coolant leak. If you find that you are losing coolant but aren't overheating check behind the motor. If you see crusted dried up coolant, you are most likely leaking from a little nipple on the coolant cross over pipe. You will see a little 1/4 hose going straight into the pipe, the little nipple is what the hose connects to, replace the nipple and crush washer. Another cause could be the cross over pipe itself, which is a PITA to replace.
18. 1.8T coolant leak. Coolant leaks on the 1.8T are many, first check the obvious, coolant resivoir, radiator, CTS sensors. If those are ok look behind the motor, you will probably find coolant running behind the cylinder head and on to the trans, this is from a leaking coolant flange, you must replace the ENTIRE flange! Do not try replacing the O-ring, it won't work, trust me.
19. Power steering whine. If you hear whining from the power steering pump check the fluid. VW/Audi power steering fluid is a mineral based fluid that will evaporate over time. It has to be topped off every 15k, so keep some in stock in your garage. After adding fluid you have to aerate the fluid. To do this, leave the cap off the P.S. resivior, and turn the wheel lock to lock until the sound goes away.
Edit: Additions
20. Peeling or rubbing off of the button displays. Your fingernails are your worst enemy when it comes to plastic numbers/words being worn off, your fingernails are a hard substance and will natually rub off the softer plastic material. Its a more common complaint with women owners that have long nails. Basically can't do anything about this short of replacement of the button or switch.
If you see peeling or bubbling of the button/s this is another common problem, most people think its the sun that causes the issue. This isn't entirely untrue, but its more likely caused by cleaning products, soda, coffee, and the buttons are overall cheaply made. Try to keep any and all polishing compounds away from any of your electronic buttons/devices. Armor all is another compound that will attack the plastic.
21. Sunroof acting possessed. If you notice that your sunroof is acting like its being controlled by the devil, then chances are the switch (potentiometer) is dirty or faulty. What you should do first is take out the switch (above your head) and clean the contacts with some electrical contact cleaner, then give it a try. If it doesn't work the way it should just replace the switch, its not a very expensive part.
If i think of any more i will add to it, but seriously look these over.
Last edited by auditech79; 03-29-2010 at 10:53 PM.
#2
04-10-2009, 11:27 PM
Having a issue with fuel system....engine doesn't start smoothly after gassing. My mechanic said that a fuel pump which was replaced not too long ago could be defect. Replaced with new fuel pump at the same shop for free of charge. Still having the same problem. Do you have any ideas what could be wrong? It is heard to believe these 2 new pumps were both defects.... I drive 2003 A4 1.8TQ.
#3
04-27-2009, 08:56 AM
Haven't had any of these problems (yet) but I definitely appreciate this!
Also, you might want to add the thing about the B6 wiper transmission, I hear that is a semi-common problem where they slowwww downnnn and then stop working (or in my case, break, then flop all over). Something to do with a bad seal and one of the bolts oxidize or something, I'm sure you can explain it better. Also the sunroof switch thing, and maybe even a heads up about the "peely switches"...
But as it is now, its still excellent, and a HUGE thanks for it!
Also, you might want to add the thing about the B6 wiper transmission, I hear that is a semi-common problem where they slowwww downnnn and then stop working (or in my case, break, then flop all over). Something to do with a bad seal and one of the bolts oxidize or something, I'm sure you can explain it better. Also the sunroof switch thing, and maybe even a heads up about the "peely switches"...
But as it is now, its still excellent, and a HUGE thanks for it!
#4
04-27-2009, 05:37 PM
Haven't had any of these problems (yet) but I definitely appreciate this!
Also, you might want to add the thing about the B6 wiper transmission, I hear that is a semi-common problem where they slowwww downnnn and then stop working (or in my case, break, then flop all over). Something to do with a bad seal and one of the bolts oxidize or something, I'm sure you can explain it better. Also the sunroof switch thing, and maybe even a heads up about the "peely switches"...
But as it is now, its still excellent, and a HUGE thanks for it!
Also, you might want to add the thing about the B6 wiper transmission, I hear that is a semi-common problem where they slowwww downnnn and then stop working (or in my case, break, then flop all over). Something to do with a bad seal and one of the bolts oxidize or something, I'm sure you can explain it better. Also the sunroof switch thing, and maybe even a heads up about the "peely switches"...
But as it is now, its still excellent, and a HUGE thanks for it!
#7
06-09-2009, 09:36 PM
My love for my 02 audi a4 has broken me emotionally and financially. I cannot pass emissions. Check Engine light always on. Have put APR computer upgrade. Among other mods like exhaust (magna flow). Scan reads o2 sensor pre and post cat, and cat. As the car runs in place it burns white smoke, tons of it. I had the head gasket changed and it didn't help at all. When the car runs it stops smoking. The car runs great. I have replaced hoses and sensors and that ejector pumps, hoses, spark plugs, coil packs. Can anyone help me?
#10
06-20-2009, 10:25 PM
If you have a failing CVT, the newer one that will be installed will be upgraded with a 7plate clutch pack and "supposedly" more reliable TCM.
