Error code

OBD2 P0652

OBD2P0652
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Sensor Reference Voltage 'B' Circuit Low.

Severity

moderateCan drive but performance issues may occur.

Summary

P0652 indicates that there is a low reference voltage issue in sensor circuit B, which can affect various sensors like MAP, camshaft position, or crankshaft position sensors.

Symptoms

  • Poor idling
  • Poor performance
  • No start condition
  • Intermittent condition
  • Lack of power
  • No A/C

Common Causes

  • Wiring short to ground or open circuit in the reference voltage supply
  • Corroded connections or pins
  • Chafed, melted wires
  • Faulty ECM (Engine Control Module)

Diagnosis

  1. Visually inspect the wiring harness for chafes or corrosion.
  2. Test each sensor's reference voltage signal using a multimeter.
  3. Check for shorts to ground and opens in the circuit.
  4. Verify that there is a proper 5V reference coming from the ECM.

Fixes

  • Repair chafed wires or replace faulty sensors.

FAQ

What should I do if I can't find the issue?

Consult a service manual and consider taking your vehicle to a qualified mechanic.

Can I test the reference voltage myself?

Yes, but ensure you have basic knowledge of electrical systems or seek professional help.

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.