The manufacturer had hoped to update the turbo units used by its ten cars in the run-up to Long Beach and replace the current single turbo unit criticised by teams for its poor throttle response in favour of the twin-turbo systems used by Chevrolet and Lotus.
Honda said that it had been given permission by series officials to make the change, only for the decision to be reversed after complaints from at least one of the rival engine manufacturers about the interpretation of benchmarking data being used to support Honda's case for the update.
"It's a matter of written word versus verbal word," said Phillips. "We're just pulling facts together now and will get with the manufacturers to sort it out." The change could still be allowed in time for the street race in Sao Paulo, Brazil.
Changes to the turbo units do not incur the same ten-grid penalties as engine substitutions.