It most probably is a fault with the power supply to the secondary air pump, the pump itself or a faulty relay.
Cost would depend on what needs to be done but this should not be a very costly job.
Checking voltage supply for secondary air pump relay
? Check fuse for Secondary Air Injection (AIR) Pump Relay -J299-.
If the fuse is not faulty:
The secondary air pump relay is located in the E-box in the plenum chamber.
? Remove secondary air pump relay from relay carrier.
? Test voltage supply (B+ 30) for relay.
If no malfunctions are identified in the voltage supply for the relay.
? Replace Secondary Air Injection (AIR) Pump Relay -J299-.
Tuesday, June 7th, 2011 AT 1:56 PM