Dick,
First a word about the codes in general. The computer stores a code when it does not get the electronic signal it is expecting based upon the perameters built into the program.
For example, if it expecting a signal between 0.34 volts and 4.7 volts it will record a code if it gets a signal lower or higher than what is expected. The code will tell you which sensor is out of range (high or low).
While the code may mean that the sensor is malfunctioning, this is not necessarily the case. The computer may have recorded a code because the signal was interfereed with due to a shorted wire, an open wire, or a poor or broken connection.
Your SHO is now 11 years old. Check your connections for corrosion. Even a slight coating of oxydation on the connections can interfere with the conduction of the electrical signal, especially when the signal is measured in the mili-volt or micro-volt ranges.
If you want the 5 step process for testing the DIS, and you have (or have access to) a LED test light ( not incandescent), or a Digital Multi-Meter (not analog or swing needle), you can do a search for it, or get back to us and I will post it again.
In answer to your question, yes your new DIS could be faulty.
IMHO you have a connection problem. I based this opinion on the fact that after you unplugged you old DIS, and then plugged it back in, your SHO ran fine. It would seem that the unplugging, and plugging back in, reestablished a good connection. rangerj
