Just a little info I have on the P0445 fault I have a had with my E39 530 sport since April.
The engine management light come on around the beginning of April. Using the Android App Torque on my HTC, I got the fault Fault code P0445 (Evaporative Emission Control System Purge Control Valve Circuit Shorted). I also got fault codes P0171 and P0174 (fuel trim bank 1 and 2 too lean), but these have not been a problem since and have been cleared. I changed the purge valve, cleared the fault, but it would come back. During this time it passed the MOT, with the engine light being noted.
After some time spent with DIS, I got the same error with another code:
DME 44 DME Activation of solenoid valve, tank vent short circuit to negative (P0445 Evaporative Emission Control System Purge Control Valve Circuit Shorted)
In June, Deutschtek garage, Glasgow, tested the wiring, the new valve, and performed a smoke test. All tests were passed. They tried to activate the valve with the diagnostic software, but this failed. Their conclusion was a faulty DME.
On Monday the 31st of July, I sent the DME to ECU Testing Ltd. Automotive ECU Testing - ECU Repair and Exchange On Tuesday, I got a phone call from them, saying that it was a more complex unit and that it would be sent to another department for testing. On Friday the 10th of August, I had another call to say that a fault was detected and was repairable. They were given the go ahead and I recieved the DME the next day (Saturday). Cost £310 with VAT and postage.
It was plugged straight in, reconnected the battery and the car started, but the fault remained. I cleared the fault and has stayed off since.
This problem was not stopping me using the car, but was out of action for nearly two weeks while waiting for the repair. It was also the most straight forward repair, as the ECU/DME is coded to the vehicle. A replacement would need recoding at the least, if not the keys and locks. I did not get a quote from BMW, but suggestions were about £1000 for a blank DME, with possibly extra to be coded.
I am just glad that its fixed and that light has gone out. Until the next time.