OEM Vendor Audit Preparation for Auto-Component Suppliers: Maruti, Tata, Mahindra, Bosch

A finance controller at a ₹180 crore Tier 1 in Manesar opens the Maruti vendor portal on a Tuesday morning to a message confirming the annual SVA window. Eight weeks. Maruti’s checklist runs to 124 items across four dimensions. Three weeks later the same controller receives the Bosch portal notification confirming a BVDA window six weeks after the Maruti SVA closes. Two audits, partially overlapping document packs, both demanding finance-dimension evidence the company has never assembled in one place before. The 90-day preparation schedule starts immediately.

This guide is the OEM vendor audit preparation auto supplier India playbook — the finance-dimension document pack per OEM, the 90-day schedule for a combined SVA-plus-BVDA cycle, and the audit-day deliverables that hold up under scrutiny from the OEM vendor development team.

Quick reference

What does the Maruti SVA look at in the finance dimension?

The Maruti SVA’s finance / commercial sub-checklist runs 28 to 34 items depending on the supplier category. The core probe:

• Scheduling agreement coverage list with price-tier verification against the SA-pricing master in MASI (Maruti’s supplier system).
• e-Nagare delivery-schedule adherence — call-off receipt to dispatch to GRN trace per part per delivery window.
• Three-month sample of dispatched-quantity to invoiced-quantity to paid-amount per part with reason coding for any variance.
• Debit-note resolution log with ageing buckets — Maruti flags debit notes past 180 days as a financial control weakness.
• RMPV claim history with constraint-policy alignment.
• Financial-health KPIs — turnover, EBITDA, working-capital cycle, debt-equity ratio.
• Tier 2 supplier development evidence per critical sub-component.

The audit-day artifacts are a digital and physical binder per item. Maruti’s audit team interviews the finance head and the commercial head with a structured question set.

What does the Tata SQUA test?

The Tata SQUA layers a sustainability dimension on top of the quality and supply dimensions and adds a GST-and-tax-compliance sub-checklist:

• 12-month GSTR-1 filing trend with reconciliation to revenue ledger.
• 12-month GSTR-2B reconciliation pack with ITC claimed reconciled to GSTR-2B.
• Four quarters of ITC-04 filings on free-issue steel with challan-out / challan-in / processing-yield / challan-back reconciliation.
• Section 143 of the CGST Act compliance on one-year free-issue return — any overdue stock flagged for resolution.
• Form 26AS three-way match for the year with explanation for any variance above 1% materiality.
• Sustainability evidence — carbon footprint per tonne shipped, water reuse percentage, supplier diversity metrics.

Tata’s emphasis on GST hygiene reflects the OEM’s own ITC claim risk. A Tier 1 with stale ITC-04 filings creates a Section 143 deemed-supply exposure that ripples back to Tata’s ITC claim.

What does the Bosch BVDA test on Section 393 / 394?

The Bosch BVDA’s finance-dimension sub-checklist is the most explicit about the new TDS / TCS framework. The questions cover:

• Section 393(1)(a) code 1002 deduction on job-work invoices paid to heat-treatment, plating, machining, and assembly vendors — sample 30 invoices over the period and verify TDS at 1% or 2%.
• Section 394 code 1071 collection on scrap sales from 1 April 2026 onwards — sample 15 scrap-sale invoices and verify TCS at 1% on the gross value before GST.
• Monthly deposit timeliness against the 7th-of-next-month deadline with verification of challan receipts.
• Quarterly Form 26Q (TDS) and Form 27EQ (TCS) filings on time with the correct payment codes.
• Form 16A and Form 27D issuance to deductees and collectees within the 15-day window.
• SupplyOn portal compliance — ASN accuracy, returnable packaging KLT-bin tracking, e-invoice and e-way bill per dispatch.
• Section 413 code 1062 on any non-resident payment for engineering services or tooling vendors abroad.

A clean BVDA finance dimension requires a Section 393/394 compliance pack with all monthly deposits and quarterly returns filed on time and zero un-deposited TDS at the audit date.

What does the Mahindra MGE focus on?

The Mahindra MGE applies a structured 0-to-100 score per dimension with the commercial sub-score weighting the following:

• SA price-line audit specific to Mahindra’s portal-driven pricing updates — every price change must be acknowledged in the supplier’s customer master with version control.
• FOMP debit-note resolution trend over the prior 12 months — Mahindra publishes a benchmark of under 60-day average resolution.
• Tier 2 sub-supplier development log — Mahindra expects Tier 1s to maintain a documented development plan for their Tier 2 base.
• Section 143(3)(i) internal-financial-controls evidence pack from the most recent statutory audit — the controller’s certification on internal controls over financial reporting.
• Financial-health KPIs with a specific working-capital cycle benchmark per Mahindra’s category-of-supplier tier.

The 90-day preparation schedule for a combined Maruti SVA plus Bosch BVDA audit

Days 1 to 30 — document pack assembly

• Week 1: SA-to-bank-receipt trail per OEM. For Maruti, 12 months of e-Nagare call-off to dispatch to GRN to invoice to payment per part per programme. For Bosch, 12 months of SupplyOn ASN to dispatch to GRN to invoice to payment per part.
• Week 2: Debit-note resolution log per OEM with ageing. Maruti’s checklist flags debit notes past 180 days — list every open debit, age it, and prepare either acceptance journal or dispute file.
• Week 3: RMPV claim file with constraint-policy tier per claim. ITC-04 evidence for the four quarters with challan-out / challan-in / processing-yield / challan-back reconciliation. Form 26AS three-way match working.
• Week 4: Section 393/394 deposit ledger with monthly challans and quarterly Form 26Q / 27EQ returns. Quality reserve / FOMP provision walk per OEM.

Days 31 to 60 — internal walk-through

• Week 5: Dry-run each document pack against the published OEM audit checklist. Note exceptions per item.
• Week 6: Fix exceptions — file overdue ITC-04, deposit any un-deposited TDS/TCS with interest under Section 466, resolve aged debit notes, reconcile Form 26AS variances.
• Week 7: Anticipated-finding register with management response template per anticipated finding.
• Week 8: Brief the front-line operations team — production heads, quality heads, supply heads — on the audit window and the questions they may face.

Days 61 to 90 — audit ready

• Week 9: Mock interview the senior team — CFO, finance head, controller, commercial head, procurement head — with the OEM’s structured question set.
• Week 10: Finalise the audit-room set-up with physical document binders per audit and digital access for portal-data probes.
• Week 11: Confirm reconciliation deltas are within 1% materiality threshold. Repeat any mock testing that failed.
• Week 12: Final readiness review with the CFO. Confirm date of OEM audit. Brief the front desk and security on visitor management.

Worked example: a Manesar Tier 1 combined audit cycle

A ₹180 crore Manesar Tier 1 supplying both Maruti and Bosch. Maruti SVA window — 18 to 22 August. Bosch BVDA window — 6 to 10 October.

The 90-day schedule starts on 20 May. Document pack assembly identifies 14 exceptions: 8 debit notes past 180 days at Maruti (₹38 lakh exposure), 2 quarters of ITC-04 filings 45 days overdue (no deemed-supply triggered yet, within the one-year window), 14 Section 393(1)(a) code 1002 deductions on heat-treatment vendor invoices under-deducted by ₹2.6 lakh (deposited with Section 466 interest of ₹18,500), Form 26AS variance of ₹4.8 lakh on one quarter (resolved through TDS reclassification with deductee).

The internal walk-through phase resolves all 14 exceptions by 19 July. The audit-ready phase confirms reconciliation deltas within 1% across all packs by 12 August. The Maruti SVA on 18 to 22 August closes with 2 minor findings — both related to e-Nagare ASN accuracy on returnable KLT-bin tracking, both addressed in the corrective action plan within 30 days. The Bosch BVDA on 6 to 10 October closes with 1 minor finding — SupplyOn ASN delay on 4% of dispatches, addressed in the corrective action plan within 30 days. Both audits maintain the supplier’s preferred-supplier status.

Tax overlay specifics

The OEM vendor audit’s finance dimension exposes the tax overlay to OEM scrutiny in a way the statutory audit does not. The combined SVA plus BVDA preparation forces the Tier 1 to assemble a Section 393 / 394 compliance pack that statutory audit covers in less detail. Three operational disciplines result:

1. Monthly deposit timeliness becomes a board-reviewed KPI.
2. Quarterly Form 26Q / 27EQ filing becomes a calendar event with controller sign-off.
3. Form 16A / 27D issuance becomes a deductee-side service commitment.

The ACMA-published guidance on supplier development and the ICAI Standards on Auditing provide the framework. The CBDT new-framework codes are the operational tax overlay.

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