Skip to content
Skip to content

OBD-II Code

P0AF5

Severity

Not yet reviewed

Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.

Can you drive it

We cannot say

Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.

Indicative cost (USD)

$180–$15,000+

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

$180 (re-terminate sense lead) to $1,800 (BMS connector replacement) to $15,000+ (full pack on a Bolt or Mercedes plug-in).

P0AF5 sets when the BMS sees the voltage-sense "C" circuit reporting ABOVE the expected range — typically above 4.5V on a Li-ion sense input or above ~8.5V on a NiMH stick input — which the controller interprets as a shorted-to-high-voltage or open-circuit condition on the sense lead.

How a shop works this

Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.

  1. Note every code that is set, not just this one.

    Codes that appear together usually narrow the cause faster than any one of them read alone.

  2. Read the freeze frame — the conditions the fault was recorded under.

    Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.

  3. Confirm the fault is current rather than history.

    Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.

  4. Then follow the diagnostic notes further down this page, in the order they are written.

    They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.

If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.

Common symptoms

  • Check engine light
Read the full diagnostic procedureP0AF5 sets when the BMS sees the voltage-sense "C" circuit reporting ABOVE the expected range — typically above 4.5V on a Li-ion sense input or above…

P0AF5 sets when the BMS sees the voltage-sense "C" circuit reporting ABOVE the expected range — typically above 4.5V on a Li-ion sense input or above ~8.5V on a NiMH stick input — which the controller interprets as a shorted-to-high-voltage or open-circuit condition on the sense lead.

The cheapest-first ladder

  1. scan-tool per-module voltages and look for the group reporting absurdly high (a sense lead that's open often floats up to rail voltage at the BMS input).
  2. Cross-check against pack-level voltage at the service plug after the safety lockout procedure — if pack voltage matches the sum of the other modules but one input is reading high, the sense lead is open, not the module.
  3. Inspect the BMS connector for pushed-out pins or a corroded socket where pin contact has been lost.
  4. Per-cell Li-ion should sit 3.6-4.2V (4.2V is full charge, 3.0V is the lower discharge limit, 2.5V is permanently damaged);
  5. NiMH per-stick is 7.2V nominal, 8.4V at full charge.
  6. HV pack voltage sense reads 200-650V scaled at the controller depending on platform.
  7. DO NOT probe HV orange-wire circuits with a standard multimeter.
  8. Always service HV with Class 0 1000V gloves, isolation tester (Megger), and DC-rated lugged probes.
  9. 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 patterns2004-2009 Toyota Prius Gen2 throws P0AF5 most often from an open sense lead at the ring terminal — corrosion cracks the copper terminal at the crimp,…
  • 2004-2009Toyota Prius Gen2 throws P0AF5 most often from an open sense lead at the ring terminal — corrosion cracks the copper terminal at the crimp, the lead disconnects, and the BMS input floats high. A re-terminate with a fresh ring lug and proper crimp is the fix.
  • 2010-2015Prius Gen3 shows the same pattern plus a documented BMS connector socket-tension issue where the female pin loses spring tension after repeated service.
  • 2011-2015Chevy Volt Gen1 throws P0AF5 after a Voltec service where the LBC was disconnected and reconnected without verifying pin engagement.
  • 2017-2019Bolt EV throws P0AF5 from the LG cell-module pack as a high-side complement to the more common P0AF4 — both are recall territory.
  • 2016-2021Mercedes-Benz hybrid (S550e, GLC350e, E350e) throws P0AF5 from a known sense-harness issue at the pack bulkhead on the P2 hybrid architecture.

Estimated repair$180 (re-terminate sense lead) to $1,800 (BMS connector replacement) to $15,000+ (full pack on a Bolt or Mercedes plug-in).

Look up another code

More free tools

VIN DecoderDecode year, make, model, engine, recalls.Maintenance ScheduleOil, timing belt, fluids, by vehicle.Tire SizeOEM vs new — diameter delta + speedo error.Gas CostWeekly, monthly, annual fuel math.

See all 9 tools