P0652 code meaning
Sensor Reference Voltage B Circuit Low
Powertrain system Generic code P06xx codes Check engine light
What P0652 means
The engine module feeds several sensors (camshaft, pedal, pressure sensors) from separate regulated 5 V reference circuits; 'B' is circuit 2. A short at one sensor pulls the whole reference down, so every sensor on it reports at once – unplug them one by one until the reference returns to 4.8–5.2 V. P0652 means reference B is too low – usually the 5 V line or a connected sensor is shorted to ground. GM's 6.6 L Duramax LB7/LLY (2004–05) sets it below 4.7 V for 2 s; GM Europe's 2.0 L turbo after 1 s or 10 s cumulative, each with the lamp in the first trip. Newer GM engines report it under the collective code P0651, and Ford does not use P0652. All sensors on the circuit then read low, with matching codes, limp mode and possibly starting problems.
P0652 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor1 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0652
- Check engine light
- Several 'low' sensor codes at once
- Limp mode or reduced power
- Starting problems
Common causes of P0652
- Most likely5 V reference wire shorted to ground (chafing)
- Most likelySensor on the reference circuit shorted internally
- PossibleMoisture or corrosion in a connector
- Less likelyModule
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Sensor reference voltage circuitSensor wiringEngine control module
What each part of P0652 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 6 | Area: computer (engine control module) and output circuits. |
| 52 | The exact fault in that area. |
What to do next
- Note P0652 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0652
What does P0652 mean?
P0652 means "Sensor Reference Voltage B Circuit Low". The engine module feeds several sensors (camshaft, pedal, pressure sensors) from separate regulated 5 V reference circuits; 'B' is circuit 2. It is a generic code, so it means the same on every make.
Is it safe to drive with P0652?
Drive gently and only to a workshop. With P0652 the car can go into limp mode (reduced power) to protect itself.
Will P0652 fail an emissions test?
Yes, it can. P0652 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0652 to fix?
Difficulty: medium. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will P0652 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.