Brake yellow warning light with C1643 and C1644 diagnostic code

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That OBD2 scanner may not be toyota hybrid compatible, as the posted OBD2 codes (DTCs) don't appear to be applicable. Many will use a "mini-vci" cable with a copy of techstream on a windows device, this is the same software that the dealership techs will use. Others get by with a OBD2 bluetooth adapter and a phone App like Dr Prius or Torque.

Read this site before buying an adapter : Hybrid battery diagnostic and repair tool for Toyota and Lexus

If you have access to other OBD2 readers in the area, you should try rescanning with those as well.

 

Let me rephrase then, the reported DTC (code) doesn't appear to be related to the gen2 prius (do a search to confirm). You might try using another App (or Techstream) with an appropriate adapter and see if you can retrieve a different OBD2 code / DTC result.

 

Was IPA (Intelligent Park Assist) not available as an option on any Gen 2 option packages in the US?

 

Since @mubasherusman is in India, his car may have been built for sale in Japan and then exported later as a used car. Such vehicles don’t necessarily have the same DTCs as those sold elsewhere, especially for features such as Intelligent Parking Assist (IPA) that were offered, at the time, only in Japan.

DTCs C1643 and C1644 indicate that the IPA system has received a trouble report from, or been unable to communicate with, the brake system. The actual problem may be indicated by DTCs stored in the skid control ECU, the computer that runs the brake system, but perhaps the scan tools used so far haven’t been able to communicate with this computer. @SFO's kind suggestion to use a more capable diagnostic system—preferably Toyota Techstream software—is the best way to proceed.

It may be also necessary to refer to the Japanese edition of the Electronic Technical Manual (電子技術マニュアル) for the NHW20 series, published on CD-ROM. At this writing, a few copies are offered in Yahoo! JAPAN auctions; I didn’t check if their sellers would export directly or via a buying service.

That’s difficult to say from the information available. The safest course is to assume that any brake-related problem could be dangerous until proven otherwise.

 

This thread is a reminder of a couple useful things to remember:

First, while there are code readers that can get all the info from a Prius and readers that can't, that's not the same thing as getting a code from a reader and thinking it has showed you the code wrong. The codes come from the car as (at least in the Gen 2s and 3s) a sixteen bit number: you use two bits to pick the letter P, C, B, or U, the next two pick a digit 0 to 3, and each next group of four bits to choose from 0 1 2 3 4 5 6 7 8 9 A B C D E F.

Those rules don't change for manufacturer-specific codes; a code reader might not "know" the code, but that doesn't mean it'll show the code wrong. (More likely is a reader may show the wrong explanation for a code, mixing it up with what some other car uses the code for.)

The other thing is that the codes are best looked up in the repair manual specific to the car. They just aren't all going to come up in Google searches, and even when they do, Google could be finding posts about other cars, or cars in other markets, or posts by people guessing.

 

That only started in 2010 with introduction of the new Gen3 and the Advanced Technology Package upgrade.