- The battery cable terminals are not covered with deposits and are securely tightened at the contact terminals.
- Battery cables are in good condition (see subsection 4). If necessary, replace the wires.
- The battery passes all tests (see subsection 3). Replace the battery if necessary.
- The starter wiring and connectors are in good condition.
- The starter bolts are securely tightened.
- The fuses in the engine compartment block have not blown (see chapter 12). If a blown fuse is detected, determine and eliminate the cause, then replace it.
- The functionality of the ignition switch electrical circuit is confirmed (see _ chapter 12).
- Starter relay is operational (it is located in the fuse/relay box, which is located in the engine compartment). The procedure for checking the functionality of the relay is described in chapter 12.
- PARK/NEUTRAL selector position sensor is operational (see chapter 7). The functionality of this system is ensured by the supply of power from the battery to the starter relay.
2. If, under the above conditions, the starter does not turn on from the ignition switch, check the voltage supplied from the battery to the solenoid valve. This test will determine whether the valve is receiving sufficient voltage from the ignition switch. Connect a test lamp or voltmeter to the contact terminal of the solenoid valve, then ask an assistant to turn the ignition switch to position "START". If after this the presence of voltage is not detected in the circuit, you should inspect the ignition switch, wiring, all fuses and starting system relays (see electrical diagrams given in chapter 12). If during the test the presence of voltage is determined, but the electric motor does not turn on, it is necessary to remove (see subsection 13) and place the starter on the workbench to test it (see subsection 4).
3. If the starter shaft rotates slowly, it is necessary to check the starting voltage of the electric motor and determine the current drop in the starter-battery circuit. This test is carried out with the starter installed on the vehicle. Operate the starter for about ten seconds (or less). Measure the battery voltage while rotating the crankshaft. The voltage should be at least 8.5 V. Also determine the current drop using an ammeter. This value should be no more than 350 A. If the current drop exceeds the established limit, contact a company station to diagnose the starter. A number of factors influence the starting torque potential of a starter. The battery must be in working condition, and its parameters must not be reduced. Make sure that the battery condition has been checked thoroughly. The battery terminals must be securely tightened. The contact leads and terminals must be free of corrosive deposits. If the test is performed at low ambient temperatures, it is necessary to pre-warm the battery and/or engine.
4. If voltage is supplied to the starter, but the rotor does not rotate, remove the traction solenoid from the starter installed on the workbench. The solenoid valve has probably failed. Motor jamming is less common. To rule out this cause, try turning the crankshaft pulley before performing the following steps. Secure the starter with the solenoid valve in a bench vice and connect the wire connected to the positive pole to the contact terminal of the starter marked "B+". Connect the other wire connected to the negative terminal of the battery to the starter housing (see illustration). Install the starter switch and apply battery voltage to the solenoid terminal marked S (do not apply voltage for more than 10 seconds). In this case, the solenoid rod, lever and clutch should move out, followed by rotation of the gear. If the drive extends but the gear does not rotate, the solenoid is good and the starter motor is faulty. If the solenoid valve clicks, but there is no movement, it means the solenoid and/or starter has failed. If, after applying voltage, the drive extends and the gear rotates, it means that the starter/solenoid valve is operational.
12.4. Scheme for testing a removed starter