How to Replace the Alternator on a 2020 Mazda CX-5 (DIY Guide)
Step-by-step instructions with required tools/parts, safety tips (i-ELOOP), and charging voltage checks for 2017, 2019, 2020, 2022, 2023
How to Replace the Alternator on a 2020 Mazda CX-5 (DIY Guide)
Step-by-step instructions with required tools/parts, safety tips (i-ELOOP), and charging voltage checks for 2017, 2019, 2020, 2022, 2023
🔧 CX-5 - Alternator Replacement
Replacing the alternator on your CX-5 involves disconnecting the battery, removing a few intake/cover parts for access, releasing the serpentine belt tension, then unbolting and unplugging the alternator.
Before I give the exact bolt locations, access path, and Mazda-specific torque specs, I need 2 quick details because the steps can change.
Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours
⚠️ Safety & Precautions
- ⚠️ Disconnect the battery negative terminal first to prevent short circuits at the alternator power cable.
- ⚠️ Let the engine cool fully; you’ll be working near hot parts.
- ⚠️ Never allow a tool to bridge the alternator B+ terminal to ground (it can arc hard).
- ⚠️ If your CX-5 has i-ELOOP (regenerative charging), follow the special battery/capacitor precautions before disconnecting anything.
- ⚠️ Support the vehicle securely if you need to access from below.
🔧 Required Tools
You'll need the following tools for this repair:
- Safety glasses
- Mechanic gloves
- Floor jack (rated 3-ton minimum)
- Jack stands (rated 3-ton minimum)
- Wheel chocks
- 10mm socket
- 12mm socket
- 14mm socket
- 3/8" drive ratchet
- 3/8" drive extension set
- Serpentine belt tool or 14mm wrench
- Flat trim clip tool
- Phillips screwdriver
- Torque wrench (10–80 ft-lbs range)
- Multimeter (digital)
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Alternator - Qty: 1
- Serpentine belt - Qty: 1 (recommended if worn or oil-soaked)
📋 Before You Begin
- Park on level ground, set the parking brake, and chock the rear wheels.
- Open the hood and remove the ignition key/fob from the vehicle area.
- Disconnect the battery: use a 10mm socket to remove the negative (–) terminal first, then isolate it so it can’t spring back.
- Take a photo of belt routing.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Confirm your CX-5 configuration (needed for exact steps + torque specs)
- Reply with: FWD or AWD (AWD changes access from below).
- Reply with: Does it have i-ELOOP? Quick check: there’s usually an under-hood label mentioning i-ELOOP, and the battery setup may look “non-standard.”
Step 2: Remove the top engine cover (if equipped)
- Pull upward evenly by hand to release the cover from its rubber grommets.
Step 3: Remove the intake duct/air snorkel for working room
- Use a Phillips screwdriver and flat trim clip tool to remove the clips/screws holding the snorkel/duct.
- Lift the duct out and set it aside.
Step 4: Release serpentine belt tension (do not remove the belt yet)
- Locate the belt tensioner at the front of the engine.
- Use a serpentine belt tool or 14mm wrench to rotate the tensioner and relieve belt tension.
- Slip the belt off the alternator pulley only, then slowly release the tensioner back.
- Don’t let the tensioner snap back.
Step 5: Stop here (to avoid wrong bolt/torque guidance)
- The next steps involve removing the alternator electrical connector and main power cable, then removing mounting bolts that have Mazda-specific torque specs.
- Once you answer the 2 questions above (FWD/AWD and i-ELOOP yes/no), I’ll give you the exact alternator removal/install steps with the correct torque values and the best access route for your CX-5.
✅ After Repair
- Use a multimeter (digital) to verify charging voltage at the battery with the engine idling (typically around the mid-13V to mid-14V range, depending on load/temperature).
- Check that the belt runs centered on every pulley and isn’t squealing.
- Confirm no warning lights are on after a short test drive.
💰 DIY vs Shop Cost
Shop Cost: $650-$1,200 (parts + labor)
DIY Cost: $180-$500 (parts only)
You Save: $470-$700 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.
🎯 Ready to get started?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.


















