Note: Before starting work, refer to the "Precautions" given in Chapter 1 this Section.
1. If the starter does not work when the ignition key is turned to the operating position, this may be due to the following reasons:
- a) The battery is faulty.
- b) Break in wiring between switch, traction relay, battery or starter.
- c) The traction relay is faulty.
- d) Mechanical or electrical failure of the starter.
2. To check the battery, turn on the headlights. If they dim after a few seconds, your battery is dead. Charge it (see Chapter 2) or replace. If the headlights are bright, observe them with the ignition on.
If they dim when the ignition is on, then the wiring is in good order, and the reason for the starter failure lies in the starter itself. If the headlights do not dim when the ignition is on (and there are no clicking sounds coming from the starter traction relay), then there is damage in the circuit or in the traction relay (see below). If the battery is good and charged, but the starter turns slowly, this indicates a faulty starter or significant resistance in the circuit.
3. If damage to the circuit is suspected, disconnect the wiring from the battery (including grounding), starter/solenoid wiring and engine/transmission ground. Clean the contacts thoroughly and repair the connections, then use a voltmeter or test light to verify that there is battery voltage at the positive terminal of the solenoid and that the ground is secure. Apply petroleum jelly to the battery terminals to prevent corrosion. Corrosion of connections is the most common cause of electrical system failure.
4. If the battery and all connections are good, check the circuit by disconnecting the wire from the traction relay terminal. Connect a voltmeter or test lamp between the end of the disconnected wire and ground (for example, the negative terminal of the battery) and check if battery voltage appears in the wire when the key in the ignition switch is turned to the start position. If yes, then the circuit is OK, if not, check the wiring as described in Section 12.
5. The traction relay contacts can be checked by connecting a voltmeter or test lamp between the positive battery terminal on the traction relay and ground. When the ignition key is turned to the start position, the voltmeter should indicate battery voltage or the lamp should light. If nothing happens, the traction relay is faulty and should be replaced.
6. If the circuit and traction relay are in good condition, the starter is damaged. In this case, you can show the starter to a specialist, but first make sure that the cost of repairs will not exceed the cost of a new starter.
[This article was previously published on the resource AudiManual.ru]