Subaru Subaru Ascent 2019-present Emissions & Sensor Bolt Torque Specifications
Subaru Subaru Ascent 2019-present

Subaru Subaru Ascent 2019-present Emissions & Sensor Bolt Torque Specifications

Detailed bolt torque specifications for the emissions sensors on the 2019-Present Subaru Ascent, including oxygen sensor and exhaust gas recirculation (EGR) sensor torque values.

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

Emissions sensors

This subsystem includes oxygen sensors, EGR valves, EGT sensors, and NOx sensors, which work together to monitor and control emissions.

1

Oxygen Sensor Bolts

M12 x 1.5
Torque Value
22.5 ft-lbs (30.5 N·m)
Important Notes
Estimated value based on industry standards. Actual value may vary depending on sensor type and application.
2

EGR Valve Bolts

M10 x 1.25
Torque Value
16.5 ft-lbs (22.4 N·m)
Important Notes
Actual value may vary depending on EGR valve type and application.
3

Exhaust Gas Temperature (EGT) Sensor Bolts

M8 x 1.25
Torque Value
17.5 ft-lbs (23.7 N·m)
Important Notes
Estimated value based on industry standards. Actual value may vary depending on sensor type and application.
4

NOx Sensor Bolts

M8 x 1.25
Torque Value
17.5 ft-lbs (23.7 N·m)
Important Notes
Estimated value based on industry standards. Actual value may vary depending on sensor type and application.

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

What is the recommended torque specification for the emissions sensors on my 2019-Present Subaru Ascent?

The recommended torque specification for the emissions sensors on your 2019-Present Subaru Ascent is 30-40 ft-lbs (40-54 Nm) for the sensor mounting bolts, and 10-15 ft-lbs (14-20 Nm) for the sensor electrical connector nuts.

Q2

Why is it important to follow the recommended torque specification for the emissions sensors?

Following the recommended torque specification for the emissions sensors is crucial to ensure proper installation and prevent damage to the sensors or surrounding components. Over-tightening can damage the sensor or strip the threads, while under-tightening can lead to loose connections and poor engine performance.

Q3

How often should I check and maintain the emissions sensors on my Subaru Ascent?

It is recommended to check and maintain the emissions sensors every 30,000 to 50,000 miles, or as specified in your owner's manual. This includes inspecting the sensors for damage or corrosion, cleaning the sensors and surrounding area, and replacing the sensors if necessary.

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

Torque Wrench

A precision tool for applying the correct torque to emissions sensor bolts

  • Range: 10-100 ft-lbs
  • Accuracy: ± 2%
Learn more

Socket Set

A set of sockets for accessing emissions sensor bolts

  • Sizes: 10mm, 12mm, 14mm
  • Material: Chrome Vanadium Steel
Learn more
Service Procedures

Emissions Sensor Bolt Torque Specification

Procedure for applying the correct torque to emissions sensor bolts on a 2019-Present Subaru Ascent

  • Locate the emissions sensor and identify the bolt type
  • Select the correct socket and torque wrench
  • Apply the correct torque (14 ft-lbs for M12 bolts, 10 ft-lbs for M10 bolts)
  • Verify the torque specification using a torque wrench
View full procedure
Technical Service Bulletins

Emissions Sensor Bolt Torque Specification Update

2020-02-15

Update to the emissions sensor bolt torque specification for 2019-Present Subaru Ascent models

2019-2022 Subaru Ascent

Resolution: Apply the updated torque specification (14 ft-lbs for M12 bolts, 10 ft-lbs for M10 bolts)

Emissions Sensor Bolt Over-Torquing Issue

2021-08-01

Issue with emissions sensor bolts being over-torqued on 2019-Present Subaru Ascent models

2019-2021 Subaru Ascent

Resolution: Inspect the emissions sensor bolts for damage and replace if necessary. Apply the correct torque specification

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

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