starter removal and testing: mk3 and mk4 TDI engines

Mar 16, 2014
starter removal and testing: mk3 and mk4 TDI engines
  • Starter removal and diagnostics for 1996-2006 mk4 VW TDI or Audi TDI

    Difficulty: 2/5

    related links: 1000q: B5 Passat starter removal, 1000q: 2005.5+ mk5 Jetta starter removal and troubleshooting

    Introduction

    The starting system on a VW TDI or Audi TDI fairly simple. There are only a few things that could result in a no start. This article describes starter troubleshooting and then starter removal.
    Although there are small differences over the years/models, the basic troubleshooting is pretty similar. The starter assembly consists of the starter motor and a solenoid. When you turn the ignition key to start, the solenoid pushes out the starter gear to engage the starter ring on the flywheel (driveplate if automatic transmission) and gives the motor 12V which turns the engine over. If you hear a metal on metal grinding noise after you release the key from the start position, the starter is sticking out and grinding against the flywheel starter ring when it should be retracted. The sticking is caused by excessive dirt build up on the starter shaft or a bad bearing inside the starter.

    Always disconnect both positive and negative battery terminals and make sure that there are no flammable fumes or sources of ignition nearby! Batteries give off explosive hydrogen gas and can pop and splash acid everywhere. Always wear eye protection and follow all precautions listed in the factory service manual. Take care to not touch the battery terminals together when at least one side is connected to the battery or let any metal object such as a wrench or necklace touch them together and ground!

    Parts
    16mm (or 17mm) deep socket- for the motor mount bolts
    13mm deep socket - positive cable and plastic cable bracket holder (mk3 cars)
    10mm socket - to remove battery terminals
    various extensions
    (optional) battery terminal cleaner brush, shown below
    [​IMG]

    Note - if the part number shows the "x" suffix, it indicates a rebuilt unit and may require a core charge. Brand new starters are very expensive, click the links to compare prices. New or rebuilt units typically include both a starter and the solenoid, usually about $160 not including core charge

    -Starter for manual transmission 1996-2006 mk3 and mk4 TDI (excludes mk5 Jetta)
    - VW# 02A-911-023-R (ALH engine), 02A-911-024-D (ALH and BEW engine), 02A-911-023-DX (rebuilt starter) (starter and solenoid rated for 2.0kW or 2.68hp)
    -Starter for automatic transmission automatic transmission 1996-2004
    - VW #020-911-024-A (ALH engine), VW# 09a 911 023 b (BEW engine) (starter and solenoid rated for 1.8 kw)
    -Solenoid only VW# 085 911 287 - available through the dealership for about $100, a generic part from most alternator or starter shops should cost about $60.

    [​IMG] [​IMG]

    Starter repair procedure
    Starter troubleshooting
    If the starter does not engage a second time after releasing the ignition key from "start", this is normal. You have to turn the key all the way to "off" before it will go to "start" again. That's how VWs are.

    If you have an automatic transmission, the car will prevent starting if the gear selector is not in Park or Neutral.

    If you don't see the glow plug light on when turn the key to start, it could be a bad relay 109. 2004 and newer pumpe duse cars do not have this problem, only 1996-2003 TDI have it. Relay 109 controls power to the ECU. Look at the relay panel under the dash, you may have to remove 2 or 3 screws to see the relay panel. If the relay marked 109 is black then it could have failed. The updated part is gray. The normal failure is the car dies during normal driving and then restarts once the relay has cooled. Because initial failures are related to overheating, you are more likely to see this problem during driving than cold starts.

    First determine if the problem is related to a low battery. You should normally still hear the solenoid click at the starter and detect other symptoms of a low battery. Test for at least 12V at the battery with a multimeter when the engine is off, about 14V when the engine is running. If the engine is cranking but not starting, it is not a starter problem, it is probably an air or fuel problem, or a sensor problem causing the no-start. If the battery voltage plummets when starting you could have a bad battery. For example, if it drops to 4v when cranking and the battery were good, a fuse would pop or the battery cables would be really hot.

    It could also be a faulty ignition switch. Some Jetta and Passat TDI (mk3) had a recall on this. If you have occasional problems starting but can start the car by wiggling the key in the ignition switch, in/out, left/right, the problem is probably in the ignition switch (this will only work a few times until the switch completely fails). You can test this by turning and holding the key to start. You should see at least 8V at the starter plug (terminal 50, pictured above). The problem is made worse by hanging weight off the ignition switch like other keys, etc.

    A bad or loose connection to the starter can also cause starting problems. Make sure that the electrical connections to the starter are clean and corrosion free. There is a braided heavy gauge wire going from the solenoid to the starter, this can become damaged and cause a poor connection.

    VW models after about 2000 have an immobilizer but it will still let you start the engine without a problem but will shut engine off after 1 second if there is an immobilizer problem. Another clue is a blinking immobilizer warning light on the dashboard. Click here to see 1000q: immobilizer general troubleshooting FAQ. So if the engine does start fine but quickly shuts down, there is nothing wrong with the starter. There could be something wrong with the ignition key since there is an immobilizer ring antenna on it, see the immobilizer FAQ for more details.

    The alarm system can also be faulty and prevent the ignition signal from reaching the starter solenoid at terminal 50. The alarm is part of the central convenience module (CCM) which also controls power windows, remote keyless entry.

    If you have a manual transmission, the clutch safety switch or wiring could be faulty, it can also prevent starting (The 1996-1997 passat oddly has a clutch safety switch installed under the clutch pedal but it is not connected to any sort of clutch pedal starter interlock, it is only connected to the cruise control system). There is also a relay on the fuse-relay panel under the dashboard. Mk3 have no starter interlock relay since there were no mk3 automatic transmission TDI sold in North america. Mk4 have a starter relay in position 3.

    Only do this next test if you are comfortable working on the car's electrical systems! You can put 12V directly to the starter wiring to bypass the solenoid and terminal to test the starter while it's still on the car. Remove the positive and negative plugs on the starter and apply 12V to the wiring. If the starter spins, then the problem is in the wiring, controls, or the solenoid. If the starter does not spin, then the problem is in the starter or its wire connections. The engine will turn over if it's working so be careful!

    Once you remove the starter from the car, you can also do the same test to determine if you only need to replace the solenoid.

    Here is a video that helps explain most of these points:



    Here's another video showing how to check for voltage drop when cranking:

    Removal
    Make sure that there are no sources of ignition including flammable vapors or liquids nearby! When you remove the battery terminals there may be a spark and it could ignite any exposed fuels. Although diesel fuel is not easily ignited at room temperature and pressure, always evacuate all fuel and vapors when working with the electrical system. Always remove the negative terminal first and put it back last! If you are working near or with the battery or cables remove all loose or uncovered watches, rings, necklaces and follow all cautions in the factory service manual, see the TOS Agreement for the full legal disclaimer.

    Raise the car safely as specified in the factory service manual and remove the splash shield or skid plate under the engine. You may not be able to reach the lower starter bolt from the top.

    Disconnect both the positive and negative battery terminals and safely set them aside (2x 10mm nuts). I suggest wrapping them with gloves or electrical tape so that they cannot touch the battery terminals. This would be a good time to clean the terminals wires and battery terminals with the battery cleaner brush.

    (Optional) remove the battery - it may be held down with a 13mm bolt and bracket. In some models, you may have to remove the intake air hoses and air intake to get better access.

    If you did not remove the battery terminals, go back and remove them now! Gently remove all the plugs and cables out of the cable bracket or starter. Also remove the starter positive wire (1x 13mm nut).

    Use an extension with the 13mm deep socket to remove the cable bracket that is holding the wires (1x13mm). There are a few ways to get to it, you could use a 13mm deep socket and feel for it. Its location is marked in the picture below with the red arrow. Here is a picture of the bracket from behind. It is threaded onto the 16mm (or 17mm) long bolt that holds the starter in place.
    [​IMG]

    Here is another picture with the bracket installed. Yours may slide off with a clip, mine had a 13mm nut resting on top of a 16mm starter/motor mount bolt. (Like the super deluxe shop mirror? It's the old side view mirror, left over from the OEM wide angle/blind spot mirror replacement, see 1000q: wide angle blind spot mirror install and FAQ for more details.)
    [​IMG]

    You might also be able to slip the bracket off by releasing this clip.
    [​IMG]

    Remove the 16mm (or 17mm) long bolts holding the starter to the transmission bellhousing (2x 16mm or 2x 17mm).

    For mk3 Jetta/Passat only: these bolts are connected to the motor mount on the other side. The mk4 Jetta/Golf/New Beetle does not. It's possible to remove them without supporting the engine (since there are 3 bolts in total that connect the engine to the motor mount) but it will be difficult to put back. I suggest putting a wood block and jack under the engine to hold it in place. After starter removal, immediately loosely thread the bolts back in the mounts to prevent the chance of engine sag. Optional: You can also use an engine support bracket from northern tool or harbor freight, pictured below
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    Mk4 cars need removal of a bolt holding the air conditioning bracket. It is attached in the same way that the cable bracket above is attached (with a small bolt on top of the long bolt). Again, if you have an mk4 you don't need to support the engine as shown above.

    The starter can now be removed.

    Replacement is the reverse of removal.

    If the (2x 16mm) starter bolts don't want to go back in, wiggle the motor mount or engine until it goes in. Pictured below is the bolt and the threaded end on the motor mount bracket. You can also loosen but do not remove the 3rd motor mount short bolt (1x16mm) to let you move the bracket more. Below is an mk3, yours may look slightly different. Again, mk3 and mk4 are slightly different, mk4 do not use a motor mount there.
    [​IMG]

    Here's a video of starter removal on a similar engine.