C1203 code on 03 sequoia - 2003 Toyota Sequoia

This communication code (C1203) will be set any time the check engine light comes on. The data link between the two computers becomes interrupted when there is a malfunction in the engine control computer or if the brake warning light is illuminated. The code itself is nothing to be worried about unless it won't clear and this is causing the lights for the VSC system to remain on. If this is the case then there is a problem in the communication line between the VSC computer and the engine control computer. This is extremely unlikely though. Remove the negative battery cable to erase all the memories in the on board systems then see if everything functions normally and this 1203 code disappears