P0652
Sensor Reference Voltage B Circuit Low
Sensor reference / ECM
Generic OBD-II
High
What it means
P0652 means the ECM's 'B' 5-volt reference supply — the regulated voltage that feeds several sensors — is reading low, usually from a short to ground or a shorted sensor. Because multiple sensors share this reference, they can all report wrong values at once, making the engine run poorly, lose power, or stall. Trace the short rather than replacing sensors at random.
High
Can I keep driving? Have it diagnosed soon — the 'B' reference feeds several sensors, so the engine may run poorly, lose power, or stall when they read wrong.
Common symptoms
What you'll notice
- Check-engine light on
- Several sensor codes stored at once
- Erratic or implausible sensor readings
- Rough running, reduced power, or stalling
Common causes
Most likely first
- Short to ground in the 'B' 5-volt reference circuitLikely
- A shorted sensor pulling the shared reference downCommon
- Damaged wiring or connector on the reference circuitCommon
- Faulty ECMLess often
How to diagnose & fix
Work through it in order
- Read all stored codes — several sensors sharing the 'B' reference will often flag together.
- Disconnect sensors on the 'B' reference one at a time to find one shorting it low.
- Inspect the reference wiring for a short to ground or chafing against the body.
- Measure the reference voltage (should be near 5 V) at the sensors.
- Replace the shorted sensor; if wiring and sensors are good, have the ECM tested. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0652?+
Not ideal. Multiple sensors lose an accurate reference, so the engine can run poorly or stall. Get it diagnosed before longer trips.
Can I just clear P0652?+
It returns while the reference reads low. The usual cause is a short to ground or a shorted sensor — find that first.
Related codes
Often seen with P0652
Read & clear P0652 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX