Kamui Kobayashi believes a possible fuel leak was to blame for his fiery exit from Friday's practice in Germany.
Putting in the laps in the afternoon session, the Caterham driver was forced to pull over and was seen running from his car.
Moments later a marshal ran towards the smoking CT05, spraying it down with a fire extinguisher while Kobayashi also grabbed one.
By the time the fire at the back of his car was out, his green Caterham was completely white.
He said: "In FP2 we went out for the first run early and completed ten laps. The car balance felt much better with the changes we made over lunch but it immediately felt like it was down on power, it just felt strange.
"We made a couple more mechanical changes and went back out for run two but at the end of the second lap I lost any braking power and could smell burning.
"I pulled over in Turn 16 as the rear of the car was by then on fire and ran to grab and extinguisher so I could help to put the fire out, but that was obviously the end of the session.
"It looks like it was a fuel leak that started the fire but we need more time tonight to find out exactly why that happened and then fix it."
But despite his woes, Kobayashi reckons his Caterham was feeling good, it just needs to be more reliable.
"Despite how FP2 went I'm still pleased with how the car felt today, especially in the first run I did in the afternoon," he added.
"If we can have more solid reliability I think we could have a better weekend than we've had for a while - now everyone will work as hard as possible tonight to help us do just that."