Audi Audi S5 2017-present Electrical System Bolt Torque Specifications & Ground Points
Audi Audi S5 2017-present

Audi Audi S5 2017-present Electrical System Bolt Torque Specifications

This page provides detailed torque specifications for various electrical system bolts on the 2017-Present Audi S5 (B9 and B9.5) models. Includes torque values for grounding points, sensor mounts, control modules, and other relevant electrical components.

Updated

Important Information

Safety guidelines and reference information for proper torque application

Quick Reference Guide
ft-lbs → Nm
× 1.356
ft-lbs → kg-m
× 0.138
Nm → ft-lbs
× 0.738
in-lbs → ft-lbs
× 0.083

Common Torque Patterns

Star Pattern

Used for wheels and other circular bolt patterns

Star Pattern torque pattern diagram showing proper bolt tightening sequence
Cross Pattern

Used for gaskets and cover plates

Cross Pattern torque pattern diagram showing proper bolt tightening sequence
Sequential Pattern

Used for head bolts and other critical components

Sequential Pattern torque pattern diagram showing proper bolt tightening sequence

Common Mistakes to Avoid

Over-tightening

Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.

Prevention:

Always use a calibrated torque wrench and follow specifications exactly.

Incorrect Torque Sequence

Tightening bolts in the wrong order can cause uneven pressure distribution and potential leaks or damage.

Prevention:

Follow the manufacturer's specified torque sequence pattern.

Dirty Threads

Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.

Prevention:

Clean and inspect all threads before assembly. Use new thread locker if specified.

Reusing TTY Bolts

Torque-to-yield bolts are designed to stretch and must not be reused.

Prevention:

Always replace TTY bolts with new ones. They are single-use only.

Dry vs. Lubricated

Not accounting for whether torque specs are for dry or lubricated fasteners can lead to incorrect tension.

Prevention:

Check if specs are for dry or lubricated threads. Use specified lubricant when required.

Recommended Tools

Torque Wrench (1/4" Drive)

Range: 2-25 ft-lbs
Small fasteners, delicate components

Torque Wrench (3/8" Drive)

Range: 10-100 ft-lbs
Most common automotive fasteners

Torque Wrench (1/2" Drive)

Range: 30-250 ft-lbs
Large fasteners, wheels

Angle Gauge

Torque-to-yield (TTY) bolts

Torque Wrench Care

  • Calibrate annually or after 5,000 clicks
  • Store at lowest setting
  • Keep clean and lubricated

Search Specifications

Search by component name, bolt size, or description

Torque Calculator

Convert between different torque units

Battery System

Torque specifications for components related to the vehicle's battery system, including terminal clamps and hold-down mechanisms.

1

Positive Battery Terminal Clamp

M6
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Ensures secure electrical connection to the battery. Loose connections can lead to arcing, voltage drop, and poor charging.
2

Negative Battery Terminal Clamp

M6
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Ensures secure electrical connection to the battery. Loose connections can lead to arcing, voltage drop, and poor charging.
3

Battery Hold-Down Clamp Bolt

M8 x 1.25
Torque Value
14.8 ft-lbs (20 N·m)
Important Notes
Secures the battery in place, preventing it from moving and potentially damaging the electrical system or causing shorts.

Starting Charging

Torque specifications for components of the starting and charging system, including the starter motor and alternator.

1

Starter Motor Mounting Bolt

M10 x 1.5
Torque Value
29.5 ft-lbs (40 N·m)
Important Notes
Ensures the starter motor is firmly attached to the engine block, allowing for proper engagement with the flywheel/flexplate.
2

Alternator Mounting Bolt (M8)

M8 x 1.25
Torque Value
18.4 ft-lbs (25 N·m)
Important Notes
Secures the alternator to the engine block or its mounting bracket. Prevents movement, belt slippage, and potential damage.
3

Alternator Mounting Bolt (M10)

M10 x 1.5
Torque Value
29.5 ft-lbs (40 N·m)
Important Notes
Secures the alternator to the engine block or its mounting bracket. Prevents movement, belt slippage, and potential damage.

Control Modules

Torque specifications for mounting bolts of various control modules such as the ECU, BCM.

1

Engine Control Unit (ECU) Mounting Bolt

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Holds the ECU securely in place, protecting it from vibration and physical damage, and ensures good grounding. Torque value estimated.
2

Body Control Module (BCM) Mounting Bolt

M6 x 1.0
Torque Value
5.9 ft-lbs (8 N·m)
Important Notes
Secures the BCM, safeguarding its connections and electronic components. Torque value estimated.

Power Distribution

Torque specifications for the fuse box and power distribution block.

1

Fuse Box Mounting Bolt

M6 x 1.0
Torque Value
5.9 ft-lbs (8 N·m)
Important Notes
Holds the fuse box securely, preventing it from shaking and potentially causing loose connections or short circuits. Torque value estimated.
2

Power Distribution Block Bolt

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Secures the power distribution block, prevents loosening and ensuring proper electrical contact for the block and its circuits. Torque value estimated.

Ground Connections

Torque specifications for ground strap and wire connections to the vehicle body.

1

Ground Connection Bolt (M6)

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Provides a crucial electrical path to ground. Loose or corroded connections can lead to various electrical problems.
2

Ground Connection Bolt (M8)

M8 x 1.25
Torque Value
14.8 ft-lbs (20 N·m)
Important Notes
Provides a crucial electrical path to ground. Loose or corroded connections can lead to various electrical problems.

Sensor Mounting

Torque specifications for mounting bolts of various sensors throughout the vehicle.

1

Small Sensor Mounting Bolt

M5 x 0.8
Torque Value
3.7 ft-lbs (5 N·m)
Important Notes
Holds various sensors securely in place, ensuring accurate readings. Torque value estimated.
2

Larger Sensor Mounting Bolt

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Holds various sensors securely in place, ensuring accurate readings. Torque value estimated.

Lighting System

Torque specifications for mounting bolts of headlight and tail light assemblies.

1

Headlight Assembly Mounting Bolt

M6 x 1.0
Torque Value
5.9 ft-lbs (8 N·m)
Important Notes
Securely mounts the headlight assembly, ensuring proper alignment and preventing vibration. Torque value estimated.
2

Tail Light Assembly Mounting Bolt

M6 x 1.0
Torque Value
5.9 ft-lbs (8 N·m)
Important Notes
Securely mounts the tail light assembly, preventing vibration and maintaining proper alignment. Torque value estimated.

Steering Controls

Torque specifications for mounting bolts of the steering wheel control module.

1

Control Module Mounting Bolt

M5 x 0.8
Torque Value
3 ft-lbs (4 N·m)
Important Notes
Securely attaches the control module, often in the steering wheel. Ensuring proper function and preventing disconnection. Torque value estimated.

Troubleshooting Guide

Common issues, diagnostic steps, and prevention guidelines

Common Issues

Bolt stretching, stripped threads, uneven torque patterns

Loose Components

Symptoms:
  • Rattling or vibration noises
  • Visible movement in components
  • Uneven panel gaps
Solutions:
  • Clean threads and mounting surfaces
  • Replace damaged fasteners
  • Apply proper torque in sequence
  • Use thread locker if specified

Stripped Fasteners

Symptoms:
  • Unable to achieve proper torque
  • Fastener spins freely
  • Visible thread damage
Solutions:
  • Use thread repair kit if appropriate
  • Install thread insert (HeliCoil)
  • Replace component if threaded hole is damaged
  • Upgrade to higher grade fastener if recommended

Overtightened Components

Symptoms:
  • Cracked or deformed parts
  • Broken fasteners
  • Compressed gaskets or seals
Solutions:
  • Replace damaged components
  • Use new fasteners
  • Follow proper torque sequence
  • Verify correct torque specifications

Diagnostic Steps

Visual inspection, torque verification, thread assessment

1

Visual Inspection

Inspect the affected area for any visible signs of damage or wear

  • Check for cracks or deformation
  • Look for signs of excessive wear
  • Verify proper fastener installation
2

Torque Verification

Verify the torque applied to the fasteners

  • Check the torque wrench calibration
  • Verify the torque specification
  • Compare the applied torque to the specification
3

Thread Assessment

Assess the condition of the threads

  • Check for signs of thread damage
  • Verify the thread type and size
  • Check for proper thread engagement

Prevention Guidelines

Best practices, maintenance tips, tool care

Best Practices

  • Always follow the recommended torque specification
  • Use the correct type and size of fasteners
  • Verify the torque wrench calibration regularly

Maintenance Tips

  • Regularly inspect the affected area for signs of wear or damage
  • Replace damaged or worn-out components promptly
  • Keep the work area clean and organized

Tool Care

  • Regularly clean and maintain the torque wrench
  • Store the torque wrench in a dry and secure location
  • Verify the torque wrench calibration before each use

Frequently Asked Questions

Find answers to common questions about torque specifications

Q1

Why are proper torque specifications important for electrical connections?

Correct torque ensures a secure and reliable electrical connection. Under-tightening can lead to loose connections, causing increased resistance, heat buildup, and potential arcing or intermittent failures. Over-tightening can damage threads, connectors, or the component itself, reducing clamping force and potentially causing connection issues or component failure.

Q2

Do torque specifications differ between different electrical components?

Yes, torque specifications vary significantly based on the size and material of the fastener and the connected components. For instance, a small ground wire terminal will require a much lower torque value than a large battery cable terminal. Always consult the repair manual or component specifications for the correct torque value for each connection.

Q3

What tools do I need to properly torque electrical connections?

You will need a calibrated torque wrench that covers the range specified for the electrical connections you're working on. Depending on the specific application, you may also need sockets, extensions, and adapters. Using a torque wrench is crucial for achieving consistent and accurate results; using a standard wrench can lead to undertightening or overtightening.

Q4

Can I reuse electrical bolts after loosening them?

It depends on the specific bolt. Some bolts, especially those used for critical high-current connections, are designed to be single-use and should be replaced after being loosened. Always refer to the service manual. If a bolt is deemed reusable, inspect it for damage before reuse. Consider replacing bolts if there is any indication of thread damage, stretching or corrosion.

Q5

What happens if I don't have the exact torque specification?

If you don't have the exact torque spec, do NOT guess. It's best practice to locate the correct specification in the official workshop manual or a reputable online resource. Using the wrong torque can result in both functional and safety issues as described above. A slightly undertorqued connection could lead to resistance or arcing (a fire hazard). An overtightened connection may result in a broken component.

Environmental Considerations

Temperature, humidity, and seasonal effects on torque specifications

Temperature Effects

Includes: High Heat, Cold Weather, Thermal Cycling

Temperature can significantly impact torque values and fastener behavior

Cold Weather

Effects:
  • Increased material brittleness
  • Higher torque required due to thread contraction
  • Reduced thread lubricant effectiveness
Recommendations:
  • Allow components to warm to room temperature when possible
  • Consider using winter-grade thread lubricants
  • Check torque values more frequently during winter months

Hot Weather

Effects:
  • Thermal expansion of components
  • Decreased friction in threads
  • Accelerated lubricant breakdown
Recommendations:
  • Check torque when components are at normal operating temperature
  • Use temperature-resistant thread lockers
  • Consider re-torquing after heat cycles

Humidity and Corrosion

Covers: Rust Prevention, Salt Exposure, Moisture Control

Moisture and corrosion can affect fastener integrity and torque values

High Humidity

Effects:
  • Accelerated corrosion formation
  • Reduced friction coefficient
  • Potential thread seizing
Prevention:
  • Use corrosion-resistant fasteners
  • Apply appropriate anti-seize compounds
  • Maintain proper protective coatings

Salt Exposure

Effects:
  • Rapid corrosion development
  • Thread damage
  • Seized fasteners
Prevention:
  • Regular underbody washing
  • Use of sacrificial anodes where appropriate
  • Application of protective coatings

Seasonal Maintenance

Spring, Summer, Fall, and Winter maintenance schedules

Spring

  • Inspect for winter damage
  • Clean and protect exposed fasteners
  • Check torque on critical components

Summer

  • Monitor heat-affected components
  • Check expansion-related loosening
  • Inspect cooling system mounts

Fall

  • Prepare for winter conditions
  • Apply corrosion protection
  • Verify all fasteners are properly torqued

Winter

  • More frequent inspection of critical fasteners
  • Check for salt damage
  • Monitor suspension component torque

Related Resources

Tools, service procedures, and technical bulletins

Recommended Tools

Digital Torque Wrench

A precision tool for accurately tightening fasteners to a specified torque.

  • Digital display for accurate torque settings
  • Audible and visual alerts for reaching target torque
  • Various measurement units (Nm, lb-ft, etc.)
Learn more

Torx Bit Set

A set of Torx bits in various sizes, necessary for working with specific electrical components.

  • Durable construction for repeated use
  • Wide range of sizes to accommodate various fasteners
  • Storage case for organization
Learn more

Socket Set (Metric)

A set of metric sockets, necessary for various electrical connections and grounds.

  • Various sizes to accommodate different nuts and bolts
  • Durable construction for repeated use
  • Storage case for organization
Learn more
Service Procedures

Battery Terminal Bolt Torque Procedure

Procedure for correctly tightening the battery terminals on a 2017-Present Audi S5.

  • Locate the battery terminals (positive and negative).
  • Using the correct socket or torx bit, loosen the terminal clamp.
  • Clean the battery posts and terminals, ensuring a good connection.
  • Place the terminal clamp back onto the battery post.
  • Use the digital torque wrench to tighten the terminal nut/bolt to the manufacturer's specified torque (typically 8-12 Nm).
  • Verify the connection is secure, but do not overtighten.
View full procedure

Ground Connection Torque Procedure

Procedure for correctly tightening ground connections to the vehicle chassis or electrical components.

  • Locate the ground connection point.
  • Using the correct socket or torx bit, loosen the bolt/nut securing the ground connection.
  • Clean the mating surfaces to ensure a good electrical connection.
  • Reinstall the ground connector and bolt.
  • Use the digital torque wrench to tighten the bolt/nut to the manufacturer's specified torque (typically 10-20 Nm, but may vary based on location and size).
  • Verify the connection is secure, but do not overtighten.
View full procedure

Control Module Mounting Bolt Torque Procedure

Procedure for correctly tightening control modules/units to the mounting bracket or vehicle chassis.

  • Locate the control module and its mounting points.
  • Using the correct socket or torx bit, loosen the mounting bolts if necessary.
  • Position the control module correctly.
  • Use the correct socket or torx bit to secure the module.
  • Use the digital torque wrench to tighten the bolts to the manufacturer's specified torque (typically 8-10 Nm, depending on the module).
  • Verify the module is securely mounted, but do not overtighten.
View full procedure
Technical Service Bulletins

Ground Connection Corrosion Issues

2020-05-15

Identifies issues with corrosion in specific ground connections, leading to intermittent electrical faults.

2017-2019 Audi S5

Resolution: Inspect and clean all ground connections. Apply dielectric grease to the mating surfaces and tighten to proper torque as per the torque specifications.

Battery Terminal Loosening and Intermittent Power

2021-11-01

Addresses reported instances of battery terminals loosening, leading to intermittent power delivery and starting issues.

2017-2021 Audi S5

Resolution: Inspect the battery terminal bolts/nuts for correct torque application. Clean battery posts and terminals using a wire brush and apply a thin layer of dielectric grease prior to reinstallation. Tighten to proper torque and verify secure connection.

Control Module Intermittent Communication Failure

2022-03-10

Identifies issues with control module communication that can be caused by loose mounting bolts affecting proper connection.

2018-2022 Audi S5

Resolution: Inspect all control module mounting points. Verify proper tightening using a calibrated torque wrench as per the service manual specifications, ensuring the module has a good mounting ground.

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

ASE Master Certified Technician with over a decade of hands-on experience in automotive repair and diagnostics.

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  • All specifications, including torque values, fluid capacities, and maintenance procedures, should be verified against your vehicle's factory service manual.
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