OBD-II Code
P0652
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)
$90–$900
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$90 (single sensor) to $900 (PCM + programming).
P0652 means VREF B is specifically below its lower threshold — the rail is being dragged below 4.5V (typically 3.5-4.4V) by a load somewhere on the bus.
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.
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.
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.
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.
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 procedureP0652 means VREF B is specifically below its lower threshold — the rail is being dragged below 4.5V (typically 3.5-4.4V) by a load somewhere on the b…
P0652 means VREF B is specifically below its lower threshold — the rail is being dragged below 4.5V (typically 3.5-4.4V) by a load somewhere on the bus.
This is the most common VREF fault mode
a sensor's internal Wheatstone bridge or signal-conditioning chip partially shorts to ground, the rail can't maintain its regulated 5V, and the PCM watches the feedback collapse. Shop-floor ladder, cheapest first: pull the FSM and list every sensor on VREF B for this platform. With key on engine off, backprobe VREF B at each sensor and note the voltage; you should see roughly the same low reading everywhere (3.5-4.4V if a sensor is loading the rail, ~0V if the rail is fully shorted). Now do the disconnect-and-measure dance: pull one VREF-B sensor at a time, watching the rail voltage at any other sensor. The moment VREF returns to 4.9-5.1V, the sensor you just disconnected is the loader — that's your bad part. If you've disconnected every VREF-B sensor and the rail still reads low, the short is in the wiring (chafed harness contacting ground) or the PCM's internal regulator has failed. Expensive-misdiagnosis caveat: same as P0651 — find which sensor is loading the VREF before replacing the PCM. The trap on P0652 specifically is that the PCM regulator can current-limit instead of failing hard, masking which sensor is the actual fault; pulling sensors one at a time is the only reliable isolation method. Don't shotgun-replace sensors on P0652 — disconnect-test each one for $0 instead of buying $80-300 parts.
Vehicle-specific patterns2007-2014 Toyota / Lexus platforms with the 2GR-FE or 2AR-FE engine commonly throw P0652 from a shorted fuel-rail pressure sensor or MAP sensor — Toy…
- 2007-2014Toyota / Lexus platforms with the 2GR-FE or 2AR-FE engine commonly throw P0652 from a shorted fuel-rail pressure sensor or MAP sensor — Toyota typically buses MAP + fuel-rail pressure + APP onto VREF B, so the loaded sensor takes the entire rail down and triggers multiple companion codes (P0107, P0192, P2122, etc.) alongside P0652.
- 2008-2015Honda V6 and 4-cylinder GDI applications throw P0652 from APP sensor internal shorts.
- 2010-2016Ford EcoBoost 1.6/2.0/3.5L commonly throws P0652 from chafed VREF wiring at the firewall grommet or from a shorted fuel-rail pressure sensor on the high-pressure side.
- 2008-2013GM 3.6L direct-injection V6 throws P0652 from cam position sensor internal shorts or from TPS hardware failure.
Estimated repair$90 (single sensor) to $900 (PCM + programming).
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