P0560

P0560 is a generic PCM fault meaning system voltage (battery voltage at the PCM's power pins) fell outside the expected operating range during a key-on event, either too low to maintain memory or fluctuating beyond rationality limits. Cheapest-first: before any alternator or PCM work, clean both battery terminals and the engine-to-chassis ground strap with a wire brush, then load-test the battery. A weak battery (CCA below 70 percent of rated) drops voltage under cranking to 9.0 volts or less, which the PCM logs as P0560 even though the charging system is fine. Measure battery voltage at the posts with key off (should be 12.4 to 12.8V), then at the PCM B+ pin with key on (should be within 0.2V of battery). If voltage at the PCM is more than 0.3V lower than at the battery, you have voltage drop in the power feed or the main fusible link. Expensive misdiagnosis: replacing the alternator or PCM when a $5 wire-brush cleaning of the negative cable would have cleared the code.

Vehicle-specific patterns: 2007-2014 Chevrolet Silverado and GMC Sierra 1500 hide corroded battery cable ends inside intact-looking insulation; the negative cable's crimp at the engine block builds green corrosion under the jacket and drops voltage 0.5 to 1.5V under load. 2003-2010 Ford F-150 with the 5.4L 3-valve has a TSB for the alternator's B+ stud connection corroding at the back of the alternator. 2005-2011 Dodge Ram with the 5.7L Hemi loses ground through the engine-to-firewall strap, setting P0560 plus a constellation of false sensor codes. 2002-2008 Toyota Tacoma and 4Runner crack the positive battery terminal where it bolts to the fusible link block, intermittent under vibration. Estimated repair: $40 to $620.