when its flasing 20 times, is it flashing slower than original flashing when you turn it on... if so, it could be giving you code 11 yes it flashes slower than what it does when we first turn the igniton on. i been reading this: Hello again, U2510 would stop the car from starting, this code is for a communication issue between the engine management module (PCM) and the instrument cluster. The instrument cluster is part of the immobiliser on this model, if the instrument cluster can't communicate with the PCM then the immobiliser will remain active. The only thing that concerns me on your car is the fact that the immobiliser LED doesn't flash fast when the ignition is on as it should with this fault. Neither knock sensor code should prevent the car starting and the fuel level sensor code certainly won't. I would put the most likely cause of the fault as a faulty instrument cluster which would explain why the immobiliser LED is acting as it should. To confirm this would mean checking the CAN wiring between the cluster and PCM, pins 31 and 32 of the cluster are the can wires, pins F31 and F19 are the CAN wires at the PCM. To access the PCM wiring means removing the security bolt, when you disconnect the PCM check that there's no corrosion in the connector, also check the engine bay wiring near the gearbox to make sure there is no damage to it causing interference on the CAN. The knock sensor wiring goes to M16, M31 and M32 of the PCM connector so when the connector is off I would eliminate any wiring concern to the knock sensor. could this have anything to do with it? and if so where is the pcm located, is the one on the back of the battery? cheers.