When looking into a used car’s background or preparing documents for a warranty claim, understanding the reliability of service history sources is essential. Drivers often compare dealership records, which are seen as the official source, against third-party service history checks, which vary widely in accuracy.

This guide breaks down how reliable each option truly is, what information they provide and when a third-party investigation may be more complete than dealership-only records.

1. Why Dealership Records Are Considered the Most Reliable

Main dealerships record servicing using manufacturer-approved digital systems such as:

• Mercedes Digital Service Booklet

• BMW Digital Service History

• Audi Digital Service Schedule

• Volkswagen Group Digital Service Record

• Jaguar Land Rover Online Service History

• Toyota National Service System

These systems offer:

✔ Manufacturer-verified digital service stamps

Uploaded securely by authorised technicians.

✔ VIN-linked accuracy

Records are tied directly to the vehicle’s unique identifier.

✔ Nationwide network visibility

Any authorised dealer for that brand can view entries.

✔ Warranty repair transparency

Shows repairs completed under warranty.

✔ Universal acceptance

Trusted by warranty companies, insurers and used-car buyers.

Reliability rating: ★★★★★ (Highest)

Dealership records are virtually impossible to falsify and are the gold standard for verifying dealer-performed maintenance.

2. What Third-Party Service History Checks Actually Provide

Third-party checks can be split into two types, each with very different levels of reliability.

A. Automated Data Platforms (e.g., HPI, Experian, CarVertical)

These services offer:

• Mileage checks

• MOT history

• Finance and write-off data

• Police/stolen alerts

However — they do not have access to dealership or independent servicing records.

Their checks are useful for background and risk assessment but are not a source of real service history.

Reliability for servicing information: ★☆☆☆☆ (Very Low)

B. Professional Manual Investigation Services

Some services manually contact garages to gather:

• Dealer digital servicing entries

• Independent workshop invoices

• Job sheets and repair notes

• Hybrid/EV health checks

• Duplicate documentation

• Confirmation of missing or unuploaded services

These provide real servicing data by directly approaching the garages that performed the work.

Reliability for servicing information: ★★★★☆ (High)
Accuracy depends on garage responses, but this method uncovers far more than dealership databases alone.

3. Dealership vs Third-Party Checks: Key Differences

1. Data Source

• Dealership: Official manufacturer systems.

• Third-Party Automated: Public datasets only.

• Third-Party Investigation: Direct communication with garages.

2. Accuracy

• Dealership: Always accurate for dealer-performed work.

• Third-Party Automated: No servicing accuracy.

• Third-Party Investigation: Accurate when sourced from garages.

3. Completeness

• Dealership: Partial — only shows servicing done at dealers.

• Third-Party Automated: No service entries.

• Third-Party Investigation: Can be fully comprehensive (dealer + independent).

4. Acceptance

• Dealership: Universally accepted.

• Third-Party Automated: Not acceptable for service history.

• Third-Party Investigation: Accepted when supported by garage-issued documents.

4. Why Dealership Records Often Appear Incomplete

Although dealership records are authoritative, they only reflect the work carried out at authorised centres. They do not show:

• Independent garage servicing

• Past work not uploaded digitally

• Repairs carried out abroad

• Services done at rapid-fit centres or mobile mechanics

• Paper-only service documents

• Services lost due to dealership ownership changes

As a result, many vehicles that have been properly maintained show gaps in their digital history.

5. When Third-Party Checks Are More Useful Than Dealership Records

A third-party investigation is valuable when:

✔ The car was serviced at multiple locations

✔ Independent garages performed most of the maintenance

✔ The digital dealer history has missing entries

✔ The owner has lost paperwork

✔ You’re preparing for a warranty claim and need supporting evidence

✔ You want a full picture of the car’s maintenance, not just dealer work

Dealership records alone rarely give a complete overview. Third-party investigations can connect the missing pieces.

6. How Third-Party Investigations Improve Overall Reliability

A professional service history recovery can:

✔ Trace servicing across dealers and independent garages

✔ Collect invoices, job sheets and supporting documentation

✔ Verify digital history with dealerships

✔ Confirm “no record found” where a service never existed

✔ Create a clear, chronological maintenance timeline

This reconstructs the most accurate and comprehensive version of the vehicle’s history — something no dealership or automated tool can provide on its own.

7. Reliability Comparison Summary

The most reliable solution overall is a combination of dealership records plus third-party investigation — giving an authoritative and complete view of the vehicle’s maintenance history.