Another problem with these things, the PCM requires a start voltage of at least 8.5 volts so that its microcontroller gets a proper POR or power on reset. If not the program counter is not reset to zero randomly reads code that also was not properly reset. Another cause of this lower voltage, starter kicks on, and can get a surge current of close to 800-900 amperes. Problems can be a little corrosion on the battery terminals, grounds, ignition switch that drops an extra volt or two, or a partially sulfated battery.
Common cause of this is no battery caps on a so-called maintenance free battery, hate this marketing term, electrolyte still evaporates leaving the top of the plates bone dry. Bad for consumers, good for battery replacement sales.
Putting a scope with memory across the battery terminals shows if this voltage is dropping below 8.5 volts, won't find this in any shop manual, tell you to use an ohmmeter, good way to fry it.
Getting random codes periodically is a sign of an erratic POR. Most alternators are grounded via their frames and using the cheapest oxidizing aluminum they can find. Another cause of low voltage. Another problem is lack of electroplating connectors, instead of our good EPA helping to solve problems with the waste, banned it in the USA, and if this job is exported say to Mexico or China, really don't do a very good job. EPA never solves problems, just fines you or shuts you down.
