The starter has a 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 and gives the motor 12V which turns the engine over. If you hear a metal on metal grinding noise, the starter is sticking and grinding against the flywheel starter ring when it should be retracted. This is caused by excessive dirt build-up on the starter shaft or a bad bearing inside the starter that is making it stick.
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 could pop, sending 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 (click links to compare current prices)
18mm deep socket- for the motor mount bolts
13mm deep socket- for the starter cables
10mm socket - to remove battery terminals
(optional) battery terminal cleaner brush, shown below
Note - if the part number shows the "x" suffix, it indicates a rebuilt unit and may require a core charge. Brand new starters are expensive, click the links to compare prices. New or rebuilt units typically include both a starter and the solenoid.
Manual transmission starters
-BRM engine VW# 02z 911 023 f (Bosch part)
-CBEA/CJAA engine VW# 02m 911 024a (Valeo part)
DSG (Automatic) transmission starters
-BRM engine VW# 02e 911 023 h (Bosch #0 001 123 017)
-CEBA/CJAA engine VW# 02e 911 023 l (Bosch part)
Solenoid for all BRM engine and CBEA/CJAA engine with DSG transmission: VW# 0ah 911 287 a, a generic
part may be available from many
alternator or starter shops for less
Solenoid for CBEA/CJAA engine with manual transmission: VW# 02z 911 287
If the starter does not engage a second time after releasing the ignition key from "start", this is normal and how VWs are set up. You have to turn the key all the way to "off" before it will go to "start" again.
If you have an automatic transmission, the car will prevent starting if the gear selector is not in Park or Neutral. You can't shift out of park unless your foot is on the brake.
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 voltage at the battery drops below 9V when cranking you have a bad battery. For example, if it went down to 4v when cranking and if the battery were good, a fuse would pop or the battery cables would be really hot.
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 which provides 12V, this can become damaged and cause a poor connection.
All modern Audi and Volkswagen have an engine immobilizer. It will let the engine start fine but it will shut if off after about a second. You should see warnings and the immobilizer symbol active on the dashboard. See 1000q: immobilizer general troubleshooting FAQ for more details. If the engine starts there is nothing wrong with the starter.
If you have a manual transmission, the clutch safety switch or wiring could be faulty, it can also prevent starting.
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 and disconnect-bypass the solenoid to test the starter while it's still on the car. Apply 12V to the wiring so that it provides power directly to the starter. Bypassing the solenoid won't let the starter gear teeth come out and engage the flywheel and will help isolate the problem.
Once you remove the starter from the car, put 12V on the starter wiring to bypass the solenoid and terminal to test the starter. 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 it's wire connections.
Here is a video for an older VW which helps explain many of these points:
Here's a non-VW video which shows how to check for voltage drop.
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
plastic splash shield. There are 3x T30 torx along the back and 8x T25
along the sides.
There are a few ridges at the front that can be tricky to position during
replacement - note them.
Disconnect the negative battery terminal. Then disconnect the positive terminals and safely set them aside (10mm nut each side). 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.
Remove the air filter box. See 1000q: air filter intake box removal for details.
A manual transmission car is shown, DSG (auto) is similar. The service manual says that the DSG starter should be removed from the top and moved up during removal.
Remove the ground cable (1x 13mm nut, blue arrow) and the electrical plug's
locking tab. Remove the plug (yellow arrow). Ignore the removed
Slide the rubber cover back and remove the positive cable off the solenoid
(1x 13mm nut, yellow arrow). The nut sits on top of a long 18mm bolt.
Underneath the car, remove the cable harness (1x 13mm nut, it also sits on
top of a long bolt).
Remove the 2x 18mm long bolts holding the starter to the transmission bellhousing. The starter can now be removed.
Replacement is the reverse of removal. Don't overtighten the 13mm nuts!
2x 18mm long starter bolts, manual transmission: 59 ft-lb
2x starter bolts, DSG transmission: 44 ft-lb
13mm ground wire-starter mounting nut: 11 ft-lb
13mm wire retainer-starter mounting nut: 11 ft-lb
starter solenoid positive cable nut: 11 ft-lb
ground wire, DSG transmission: 11 ft-lb
Do you have any more tips or need help removing the starter on your mk5 VW? Please post your question in the myturbodiesel.com forums