Unapproved Modifications in Used Cars: What To Watch Out For And Why They Matter

Selling or buying a used car should be a smooth process, but sometimes, hidden modifications can make things tricky. Not all upgrades are bad, but when a car comes with unapproved changes, it can void the manufacturer’s warranty, affect insurance claims, and even lead to poor performance. Sounds serious, right?

Let’s understand why this happens, what to look for, and how to protect yourself when dealing with modified cars in India.

What are Unapproved Car Modifications?

In simple terms, unapproved modifications are changes made to a car that haven't been endorsed by the original manufacturer. This means these alterations could impact the car’s safety, efficiency or mechanical integrity. Some common examples include:

• Installing aftermarket CNG kits without proper RTO approval
• Adding high-performance exhaust systems
• Altering the suspension or wheel size beyond standard fitment
• Replacing the infotainment system with non-OEM units
• Wiring additional electronic accessories like cheap DRLs, HID kits, or subwoofers without relays

While some of these may look or sound cool, they could end up causing bigger problems than they solve.

How Unapproved Modifications Can Void the Car’s Warranty

Car manufacturers provide warranties under the assumption that the vehicle remains in its original condition. If you tamper with key systems, like the engine, fuel delivery, or electrical wiring, you may breach warranty terms.

Here are some reasons:

• Engine control modules (ECMs) are sensitive. Aftermarket tuning or CNG kits may confuse the sensors and trigger warning lights or performance issues.
• Electrical systems are designed to work within a limited load. Adding unapproved accessories may cause short circuits or even battery drainage.
• Fuel system mods, especially unauthorised CNG kits, not only risk safety but often void the engine warranty instantly.
• Suspension tweaks can affect alignment, ride comfort, and even tyre wear, none of which the manufacturer would cover.

In short, if your car goes for warranty repair and they spot an unapproved mod, your claim might be rejected, even if the issue seems unrelated.

Are All Modifications Bad?

Not really. If the modification is done using genuine parts and has been approved by the RTO or manufacturer, it’s usually safe. For instance, company-fitted CNG kits in cars like Wagon R or Tiago iCNG are fully legal and supported by warranty.

Similarly, authorised service centres often provide upgrade options like alloy wheels or infotainment systems. These won’t cause trouble unless altered further.

How PDI Spot Unapproved Modifications

If you’re buying a used car, it's important to look closely. Here are a few things to check:

1. Mismatched parts or unusual welds: Check the exhaust tip, suspension setup, and engine bay. Aftermarket parts often don’t blend in perfectly.

2. Extra switches or dangling wires: These could be signs of retrofitted electronics, extra lighting, audio amplifiers, or parking sensors.

3. CNG kit branding: If it’s not from a reputed name like Lovato or Tomasetto, or doesn't have an RTO-approved sticker, it’s likely unauthorised.

4. Dashboard warning lights: A check engine light that refuses to go off might be caused by altered ECU settings or faulty sensors from modifications.

5. Unusual ride quality or vibrations: Modified suspensions or tyres that are too large can lead to bumpy rides or pulling issues.
 

For extra confidence, book a professional Pre-Delivery Inspection (PDI) from CARS24. Our experts are trained to spot tampered components and highlight modifications that could cause trouble later.

How to Stay Safe as a Buyer or Seller

If you’re selling your car, you should be transparent by mentioning about any modifications in your car. You should do it especially when it involves performance, emissions, or electronics. Buyers value honesty and it can save both parties a lot of back and forth.

If you’re buying a used car, always ask for:

• Service history from authorised service centres
• RTO approval for CNG or LPG kits
• An inspection report, if available

You can also use the CARS24 inspection or valuation service to ensure the vehicle’s condition is accurately assessed, including checking for any major modifications.

Selling Your Car on CARS24

Selling a used car with confidence is easy when you choose a trusted platform. CARS24 ensures transparency, fair pricing, and a seamless process.

Here’s how you can sell your car quickly:

1. Get a free price estimate on our website or app
2. Book a free doorstep or hub inspection
3. Get the best offer and receive instant payment once the deal is closed

We also take care of the paperwork, so you don’t have to worry about transfer delays or hidden liabilities, even for modified cars, as long as they’re declared properly.

Conclusion

Modifications can be tempting, but they come with their own risks. When it comes to warranty, safety and resale value, unapproved changes might end up costing you more than expected.

Whether you’re buying or selling, a little awareness goes a long way. And if you want complete peace of mind, let the experts at CARS24 guide you every step of the way.

Want to get started? Head to CARS24 and discover just how simple it is to sell your car the right way.