How Is PUC (Pollution Test) Done For Hybrid Cars That Start In EV Mode? Explained [Video]

In India, the law requires every vehicle to have a Pollution Under Control (PUC) certificate. The Central Motor Vehicles Act, 1989 and the Motor Vehicles Act, 1988, mandate this. Vehicles are required to undergo pollution tests periodically. Hybrid vehicles, despite having less polluting, electrified powertrains, are not exempt. Conducting PUC tests on hybrids, however, can be difficult, as these start in all-electric mode and the petrol engine comes into play only as the vehicle gains speed.

How Are PUC Tests Performed?

Pollution tests these days are fully computerised. The setup for this was developed by the Society of Indian Automobile manufacturers.

A gas analyser is connected to a computer. For diesel and petrol engines, two different methods are used to collect the samples. For petrol vehicles, the car is switched on and the engine is kept running. The accelerator is not used for the same, and the engine is left in the idle state.

For diesel vehicles, the accelerator is used to raise the engine rpm to the recommended levels. This is essential to get an accurate emission reading. Up to five sets of readings are collected and the average of these is taken as the final reading.

It records the emission value and sends it to the computer, which analyses it in detail. If the vehicle passes the test, a PUC certificate is issued.

How To Do PUC Tests On Hybrid Vehicles?

To understand this better, let''s explain with an example. Let's take the case of the Toyota Hyryder strong hybrid. This SUV starts in all-electric mode. Thus, if you start it normally at a pollution testing station, the engine will remain inactive, and no emission readings can be collected. A unique workflow is to be followed to get the vehicle into 'Maintenance mode' before trying to collect the readings. Undertake the following steps:

2. Keep your foot off the brake pedal and double click the Start/stop button to get the vehicle into the ON mode.
3. Ensure that the gear lever is in the P (Park) mode and depress the accelerator pedal twice.
4. Depress the brake.
5. Shift the lever into the N (Neutral) mode, keeping the brake engaged.
6. Fully depress the accelerator twice.
7. Fully depress brake once.
8. Shift to P mode and depress the brake twice. You will now see a 'Cdy-2E' notification on the instrument cluster.
9. Depress the brake and start the vehicle like you'd normally do.

You will now see the engine running. Keep the brake pressed and let the engine run ( you don't have to use the accelerator) enough to give the PUC testing device sufficient readings. During the process, the instrument cluster will show ' ESP Maintenance mode activated'. Once the PUC test is complete, switch off the engine and wait for 30 seconds before a restart. After this time span, the vehicle will start normally, and the 'Maintenance mode' will be automatically disabled.

What Happens If You Don't Possess A Valid PUC Certificate?

Failing to possess a valid PUC certificate for your vehicle can lead to fines and penalties. In severe cases (though rare), it could even fetch you imprisonment of up to 3 months. Previously, the fine for not having a PUC certificate used to be Rs 1000 (and Rs 2000 for repeated offences). However, the revised fine structure published earlier this year, has taken this to Rs 10,000 and up to six months of imprisonment in severe cases.