P0652: Sensor reference voltage B: circuit low
The second 5 volt supply the ECU feeds to several sensors is too low. Usually a sensor or a wire shorting to earth.
| Code | P0652 |
|---|---|
| System | Engine and transmission |
| Group | P06xx, Control unit and auxiliary outputs |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0652 means
The ECU powers a group of sensors with a fixed voltage, usually 5 volts, called reference B. This code means that voltage has dropped below normal. Almost always a faulty sensor or a chafed wire is pulling it down to earth.
Most common causes
- A sensor on the line with an internal short
- Reference B wire chafed and touching earth
- Sensor plug with water or corrosion
- Wiring loom pinched or burnt
- Internal ECU fault
Symptoms
- Engine warning light on
- Several sensor codes at once
- Limp mode or unresponsive accelerator
- Engine may not start
Can you drive with P0652?
With care The car may have very little power or refuse to start. Only drive when essential until it is repaired.
Open the bonnetthe in-depth explanation
How to check it
Check on the scan tool whether several sensors show nonsense or zero readings at the same time: that confirms the fault is in the shared supply. Take the full list of codes to the garage.
How to read and clear P0652 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0652 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P064E The internal control unit lambda sensor processor (bank 2) gives readings
- P064F An unauthorized software calibration that is not original equipment has been
- P0650 Malfunction indicator lamp (MIL) control: circuit fault
- P0651 Sensor reference voltage B: circuit open or faulty
- P0653 Sensor reference voltage B: circuit high
- P0654 The engine speed output has an electrical fault
- P0655 The engine hot light output control has an electrical fault
- P0656 The fuel level output has an electrical fault
- P0600 Serial communication link fault
- P0601 Internal control module memory checksum error
- P0602 Control module programming error
- P0603 Internal control module keep alive memory (KAM) error
What does code P0652 mean?
The ECU powers a group of sensors with a fixed voltage, usually 5 volts, called reference B. This code means that voltage has dropped below normal. Almost always a faulty sensor or a chafed wire is pulling it down to earth.
Can you drive with P0652?
The car may have very little power or refuse to start. Only drive when essential until it is repaired.
How do you clear P0652?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0652 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
