This procedure covers the removal and replacement of the alternator on a 2014-2019 Toyota Corolla with the 1.8L I4 engine, including serpentine belt removal and electrical connections.

Warnings

Tools required

Parts

• Alternator × 1 — 27060-37030 or equivalent remanufactured
• Serpentine belt (if worn or damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn ignition off and remove key from vehicle
3. Allow engine to cool if recently operated
4. Open hood and secure with prop rod
5. Disconnect negative battery cable and isolate the terminal away from the battery post

Procedure

1. 1

   Document serpentine belt routing
   Locate the serpentine belt routing diagram on the hood or radiator support. If absent, take a clear photograph of the belt path around all pulleys including the alternator, crankshaft, tensioner, A/C compressor, and water pump. This is critical for correct reinstallation.
2. 2

   Remove serpentine belt
   Using a 14mm wrench or serpentine belt tool, rotate the belt tensioner clockwise to release tension on the belt. Slide the belt off the alternator pulley first, then carefully release the tensioner. Remove the belt from the remaining pulleys and pull it out from the engine bay. Inspect the belt for cracks, glazing, or excessive wear.
3. 3

   Disconnect alternator electrical connections
   Locate the alternator on the right side of the engine. Remove the rubber boot covering the B+ terminal stud. Use a 10mm socket to remove the nut securing the main output cable to the B+ terminal. Carefully pull the cable off the stud. Disconnect the 2-pin electrical connector by pressing the tab and pulling straight out.
   ⚠Do not allow the B+ cable to contact ground or other metal components as it is connected directly to the battery positive terminal.
4. 4

   Remove alternator upper mounting bolt
   Locate the upper alternator mounting bolt on the passenger side of the alternator bracket. Use a 14mm socket with extension to remove this bolt completely. Support the alternator with one hand as the bolt is removed.
   Torque spec

   Alternator Mounting Bolts50 Nm (37 lb-ft)
5. 5

   Remove alternator lower pivot bolt
   From underneath the alternator, locate the lower pivot bolt that passes through the adjustment bracket. Use a 14mm socket with extension to remove this bolt. The alternator may now be loose in its mounting position.
   Torque spec

   Alternator Pivot Bolt25 Nm (18 lb-ft)
6. 6

   Remove alternator from engine
   Carefully maneuver the alternator upward and toward the passenger side fender to clear the mounting bracket. You may need to tilt the alternator slightly to clear surrounding components. Remove the alternator from the engine bay. Inspect the mounting bracket and adjustment points for damage or wear.
7. 7

   Prepare new alternator for installation
   Compare the new or remanufactured alternator with the old unit to verify correct fitment, pulley alignment, and electrical connector positions. Clean the mounting surfaces on the engine bracket with a wire brush. If the alternator came without a pulley, verify the pulley from the old alternator is properly transferred and secured.
8. 8

   Install new alternator
   Position the new alternator into the engine bay and align it with the mounting bracket. Maneuver the alternator into position by reversing the removal path. Align the lower pivot hole and upper mounting hole with the corresponding bracket holes.
9. 9

   Install lower pivot bolt
   Insert the lower pivot bolt through the adjustment bracket and alternator. Thread the bolt by hand to ensure proper alignment, then tighten to specification using a torque wrench.
   Torque spec

   Alternator Pivot Bolt25 Nm (18 lb-ft)
10. 10

    Install upper mounting bolt
    Insert the upper mounting bolt through the bracket and into the alternator. Thread by hand initially, then torque to specification. Ensure the alternator is seated properly in the bracket before final tightening.
    Torque spec

    Alternator Mounting Bolts50 Nm (37 lb-ft)
11. 11

    Reconnect alternator electrical connections
    Reconnect the 2-pin electrical connector to the alternator until it clicks into place. Place the main output cable onto the B+ terminal stud and install the retaining nut. Torque the nut to specification, then reinstall the rubber protective boot over the terminal.
12. 12

    Install serpentine belt
    Route the new or existing serpentine belt around all pulleys according to the routing diagram or photograph taken earlier, leaving the tensioner pulley for last. Rotate the tensioner clockwise with a 14mm wrench, then slide the belt onto the tensioner pulley. Carefully release the tensioner to apply proper belt tension. Verify the belt is properly seated in all pulley grooves.
13. 13

    Reconnect battery and test
    Reconnect the negative battery cable to the battery post and torque the terminal bolt to specification. Do not overtighten as this can damage the battery post. Start the engine and verify the alternator is functioning by checking that the battery warning light on the dashboard extinguishes.
    ⚠Battery terminal bolts must not be overtightened. Use a torque wrench and verify correct torque specification.
    Torque spec

    Battery Terminal Bolts8 Nm (6 lb-ft)

Reassembly

1. Verify all electrical connections are secure and properly routed
2. Confirm serpentine belt is properly seated on all pulleys with no twists or misalignment
3. Double-check all mounting bolts are torqued to specification
4. Ensure no tools or parts are left in the engine bay

Verification

• Start the engine and verify the battery warning light turns off within 2-3 seconds
• With engine running, observe the serpentine belt for proper tracking on all pulleys without wobbling or noise
• Use a multimeter to verify charging voltage at battery terminals (should read 13.8-14.7 volts with engine running at idle)
• Turn on electrical accessories (headlights, A/C, radio) and verify voltage remains stable
• Listen for any abnormal noises from the alternator or belt system
• Test drive vehicle and verify charging system warning light does not illuminate under various load conditions

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