P0AF6

P0AF6 sets when the BMS sees the voltage-sense "C" circuit dropping in and out — the value is in range when present but disappears or jumps erratically across a drive cycle. Intermittent codes are the hardest to chase because the fault has to be present while you're scanning. The cheapest-first ladder: pull freeze-frame and look at the conditions when the fault was set (SOC, pack temp, vehicle speed, regen-braking event), then try to reproduce. A sense lead chafing against the pack frame typically opens under vibration — a long drive on rough pavement reproduces it, idling in the bay won't. With the scan tool live-graphing the per-module voltage on the suspect group, gently flex the sense harness at each bulkhead/connector and watch for the voltage to drop or jump. A reading that glitches when you wiggle the connector identifies a pin or terminal issue; a reading that glitches when you flex a specific section of harness identifies a chafe point. Per-module voltages should hold 3.6-4.2V (Li-ion) / 7.2V (NiMH) steady within 0.02V on a stable pack. DO NOT probe HV orange-wire circuits with a standard multimeter. Always service HV with Class 0 1000V gloves, isolation tester (Megger), and DC-rated lugged probes. Voltage-sense codes (P0AF3-P0AF7) often indicate the BMS sense lead chafed at the bus-bar bolt — re-tightening with new lockwasher can fix without pack replacement.

Vehicle-specific patterns: 2004-2009 Toyota Prius Gen2 throws P0AF6 as the precursor code before P0AF3/P0AF4/P0AF5 settles into a hard fault — the sense lead is fretting at the bus-bar bolt but hasn't fully failed yet, and you'll see the intermittent set under hard regen events (downhill braking, freeway off-ramp) when the pack sees the largest voltage swings. Catching it at this stage with a re-terminate and lockwasher kit avoids module-group replacement later. 2010-2015 Prius Gen3 throws P0AF6 from the BMS ribbon-cable tab cracks — temperature cycling expands and contracts the ribbon, the solder joint fractures, and you get intermittent contact. 2011-2015 Volt Gen1 throws P0AF6 from a vibrating LBC connector that needs a fresh seal and re-seat. 2017-2019 Bolt EV throws P0AF6 as a recall-coverage early warning. Estimated repair: $180 (re-terminate + lockwasher) to $900 (BMS ribbon repair, where serviceable) to $15,000+ (pack-level work outside recall).