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Cummins Software Engineer Interview Guide

Cummins Software Engineer interview guide: reported rounds, questions and how candidates describe the process.

The 60-second brief

As a Software Engineer at Cummins, you operate at the critical intersection of software development, digital infrastructure, and advanced power technology. Cummins is a global power leader known for its engine technology, component manufacturing, and clean energy innovations. Modern engine systems, hybrid powertrains, diagnostics tools, and enterprise platforms rely heavily on complex software architectures. In this role, you build and refine software solutions that control physical hardware, analyze telematics data, and automate manufacturing and service environments worldwide. The impact of a Software Engineer at Cummins extends from the edge to the enterprise.

This guide is scoped to a Software Engineer candidate at Cummins.

Focus areas

  • Embedded Systems
  • Hardware Design
  • Hardware Diagnostics

The Cummins interview process

Cummins candidates report 3 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Initial Screening

Discuss your background and motivations in a preliminary conversation.

What to demonstrate

  • Discuss your background and motivations in a preliminary conversation
  • Depth in Embedded Systems

How to prepare

  • Be able to walk your CV end to end in two minutes, and say why this company specifically.
  • Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.

Technical Interviews

Participate in one or more interviews focused on your technical expertise and problem-solving abilities.

What to demonstrate

  • Participate in one or more interviews focused on your technical expertise and problem-solving abilities
  • Depth in Embedded Systems

How to prepare

  • Answer aloud and timed: Tell me about a time when you made a mistake on an engineering project. How did you communicate and rectify it?
  • Answer aloud and timed: Describe a scenario where you used data to solve a complex problem or developed a software solution from scratch.

Behavioral Evaluations

Share your experiences and how they align with the company's core values.

What to demonstrate

  • Share your experiences and how they align with the company's core values
  • Depth in Embedded Systems

How to prepare

  • Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
  • Re-read the description of the behavioral evaluations above and write down what you would ask to confirm before it.

Where candidates lose points

Master the STAR Method

Prepare 5–7 structured stories from your academic or professional background that highlight teamwork, conflict resolution, technical problem solving, and leadership.

Focus on Your Individual Actions

When describing past team projects, clearly specify what you personally designed, wrote, or debugged rather than speaking generically about team achievements.

Brush Up on Core Resume Language

Be ready to explain the inner workings of any language or technology you list on your resume, including memory concepts, syntax choices, and database queries.

Research Cummins Values and Products

Understand Cummins’ commitment to sustainable power solutions, diversity, and engineering quality. Mentioning these values in behavioral rounds demonstrates genuine interest.

Questions & practice

How do you manage memory allocation, pointers, and dynamic memory in C to prevent leaks?

Medium · Technical Fundamentals & Core Programmin

Approach

  1. Say what the runtime actually does before reasoning about the code.
  2. Name what is shared across threads and what owns each piece of state.
  3. Identify the window where an invariant is briefly untrue.
  4. Distinguish a value from a reference to it, and say which one you handed out.

Follow-up

  • What happens if two callers reach this at the same time?
  • Where could this allocate more than you expect?

Write a Python script to manipulate data streams or explain how you would search a binary structure efficientl

Medium · Technical Fundamentals & Core Programmin

Write a Python script to manipulate data streams or explain how you would search a binary structure efficiently.

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.

Follow-up

  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

How do linked lists compare to arrays regarding time complexity for insertion and deletion operations?

Medium · Technical Fundamentals & Core Programmin

Approach

  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.

Follow-up

  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Can you walk through a sample code snippet and predict its exact runtime behavior and memory usage?

Medium · Technical Fundamentals & Core Programmin

Approach

  1. Say what the runtime actually does before reasoning about the code.
  2. Name what is shared across threads and what owns each piece of state.
  3. Identify the window where an invariant is briefly untrue.
  4. Distinguish a value from a reference to it, and say which one you handed out.

Follow-up

  • What happens if two callers reach this at the same time?
  • Where could this allocate more than you expect?

What are the differences between continuous table expressions (CTEs) and subqueries in SQL, and when would you

Medium · Technical Fundamentals & Core Programmin

What are the differences between continuous table expressions (CTEs) and subqueries in SQL, and when would you use a WITH clause?

Approach

  1. Name the grain you start from and join outward from it.
  2. Check whether any join is one-to-many before aggregating, or the sums inflate.
  3. Say which index the query would use, and what makes it unusable.
  4. Handle the rows that do not match: that is usually the actual question.

Follow-up

  • How does the query change if that join becomes one-to-many?
  • What happens to this when the table is ten times larger?

Write the update path that detects a concurrent edit

Medium · optimistic concurrency · transactional outbox · audit history

resource carries version INT NOT NULL DEFAULT 1. resource_revision holds revision_id, resource_id, version, actor_user_id, change_kind, patch JSONB, request_id, created_at with UNIQUE (resource_id, version). outbox_event holds aggregate_type, aggregate_id, aggregate_version, event_type, payload, status. A PUT carries the version the client read. Write the exact statements for the single transaction that applies the edit, records the revision and enqueues 'resource.updated', and give the handler's branch on zero affected rows. Then say what PostgreSQL 16 does under READ COMMITTED when two of these updates hit one row at once.

Approach

  1. One transaction, three writes, no network call inside it: UPDATE resource SET title = $3, version = version + 1, updated_at = now() WHERE resource_id = $1 AND tenant_id = $4 AND version = $2; then INSERT the resource_revision row at version $2 + 1; then INSERT the outbox_event row at the same aggregate_version. The event goes to a table rather than a broker because no transaction spans both.
  2. Branch on the affected-row count before doing anything else. Zero has three causes — stale version, wrong tenant, row gone — so re-read once and map to 409 carrying the current version, or 404 for an id outside the caller's tenant, which also stops the endpoint confirming that another tenant's id exists.
  3. State the engine behaviour instead of assuming it. Under READ COMMITTED the second UPDATE blocks on the row lock, and when the first commits PostgreSQL re-evaluates the WHERE clause against the newly committed row, so the version predicate now fails and the statement reports zero rows. Under REPEATABLE READ the identical collision raises SQLSTATE 40001 instead, so the handler must fold both shapes into one conflict response.
  4. Keep UNIQUE (resource_id, version) even though the predicate already serialises writers. It is what makes a lost update unwritable if any other path ever reaches the revision table, and it converts a logic bug into 23505 rather than into a silently missing history row.

Follow-up

  • A client sends the version it read ten minutes ago and the resource has moved three versions. What is in your 409 so it can resolve the conflict without a full re-fetch?
  • Two editors, two disjoint fields, no overlap. Does your answer still refuse the second write, and should it?

Explain the difference between file types and process signal handling in a Linux operational environment.

Medium · Embedded Systems, Diagnostics & Linux En

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

How do high-level software instructions interface with Programmable Logic Controllers (PLCs) and hardware diag

Medium · Embedded Systems, Diagnostics & Linux En

How do high-level software instructions interface with Programmable Logic Controllers (PLCs) and hardware diagnostics tools?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

What considerations apply when reading from high-input impedance components or processing analog-to-digital si

Medium · Embedded Systems, Diagnostics & Linux En

What considerations apply when reading from high-input impedance components or processing analog-to-digital signals?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

How would you structure a fault tree analysis to isolate a software-driven electronic failure?

Medium · Embedded Systems, Diagnostics & Linux En

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

What is the operational distinction between a Product Owner (PO) and a Product Manager (PM) in an Agile enviro

Medium · Agile Methodology & Process Quality

What is the operational distinction between a Product Owner (PO) and a Product Manager (PM) in an Agile environment?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

How do software design iterations fit into broader quality control frameworks like Failure Mode and Effects An

Medium · Agile Methodology & Process Quality

How do software design iterations fit into broader quality control frameworks like Failure Mode and Effects Analysis (FMEA)?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

How do you document engineering designs to ensure cross-functional alignment between software, hardware, and p

Medium · Agile Methodology & Process Quality

How do you document engineering designs to ensure cross-functional alignment between software, hardware, and plant management?

Approach

  1. Clarify what is being asked and what a complete answer contains.
  2. State your assumptions explicitly before working the problem.
  3. Say what you would check first and why it is the highest-information step.
  4. Work from the requirement backwards to the design.

Follow-up

  • What assumption would you test first?
  • How would you know your answer was wrong?

What essential networking commands would you use to troubleshoot communication between remote hardware nodes?

Medium · Embedded Systems, Diagnostics & Linux En

Approach

  1. Establish what changed and when, before forming any theory.
  2. Pick a bisection that eliminates candidates whichever way it turns out.
  3. Check the instrumentation before believing the symptom.
  4. Separate the trigger from the cause; the deploy is rarely the bug.

Follow-up

  • What would you look at first, and what would it rule out?
  • How would you tell a cause from a coincidence here?

Suggested practice checklist

Built from the rounds and topics Cummins candidates report.

Day 1 — Map the Cummins loop

  • Write out the reported sequence: Initial Screening, Technical Interviews, Behavioral Evaluations.
  • For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.

Deliverable: A one-page map of the 3 reported rounds, with the weakest marked.

Day 2 — Work Embedded Systems

  • Spend the session on Embedded Systems, which Cummins candidates report being tested on.
  • Write one worked example in Embedded Systems and time yourself on it.

Deliverable: One timed worked example in Embedded Systems.

Day 3 — Work Hardware Design

  • Spend the session on Hardware Design, which Cummins candidates report being tested on.
  • Write one worked example in Hardware Design and time yourself on it.

Deliverable: One timed worked example in Hardware Design.

Day 4 — Work Hardware Diagnostics

  • Spend the session on Hardware Diagnostics, which Cummins candidates report being tested on.
  • Write one worked example in Hardware Diagnostics and time yourself on it.

Deliverable: One timed worked example in Hardware Diagnostics.

Day 5 — Answer out loud: Behavioral & STAR Method Questions

  • Answer aloud, timed: Tell me about a time you faced a significant conflict within a diverse or cross-functional team and how you resolved it.
  • Answer aloud, timed: Describe a situation where your supervisor assigned you too much work within a tight deadline. How did you handle it?

Deliverable: Spoken answers to 2 reported Behavioral & STAR Method Questions question(s), under time.

Day 6 — Answer out loud: Technical Fundamentals & Core Programming

  • Answer aloud, timed: How do you manage memory allocation, pointers, and dynamic memory in C to prevent leaks?
  • Answer aloud, timed: Write a Python script to manipulate data streams or explain how you would search a binary structure efficiently.

Deliverable: Spoken answers to 2 reported Technical Fundamentals & Core Programming question(s), under time.

Day 7 — Answer out loud: Embedded Systems, Diagnostics & Linux Environments

  • Answer aloud, timed: Explain the difference between file types and process signal handling in a Linux operational environment.
  • Answer aloud, timed: What essential networking commands would you use to troubleshoot communication between remote hardware nodes?

Deliverable: Spoken answers to 2 reported Embedded Systems, Diagnostics & Linux Environments question(s), under time.

Behavioural preparation

Behavioural rounds judge the decision you made and what it cost.

Tell me about a time you faced a significant conflict within a diverse or cross-functional team and how you re

Medium · Behavioral & STAR Method Questions

Tell me about a time you faced a significant conflict within a diverse or cross-functional team and how you resolved it.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Describe a situation where your supervisor assigned you too much work within a tight deadline. How did you han

Medium · Behavioral & STAR Method Questions

Describe a situation where your supervisor assigned you too much work within a tight deadline. How did you handle it?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Tell me about a time when you made a mistake on an engineering project. How did you communicate and rectify it

Medium · Behavioral & STAR Method Questions

Tell me about a time when you made a mistake on an engineering project. How did you communicate and rectify it?

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Describe a scenario where you used data to solve a complex problem or developed a software solution from scrat

Medium · Behavioral & STAR Method Questions

Describe a scenario where you used data to solve a complex problem or developed a software solution from scratch.

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Give an example of a time when you had to take a firm technical stand against a senior engineer or supervisor.

Medium · Behavioral & STAR Method Questions

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Describe your experience working within sprint cycles, daily standups, and backlog refinement.

Medium · Agile Methodology & Process Quality

Approach

  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.

Follow-up

  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?