P00B4 OBD II Trouble Code Radiator Coolant Temperature Sensor Circuit High

How to quickly diagnose, repair, and info on symptoms and causes of a P00B4 code that means there is a high voltage condition in the radiator coolant temperature sensor circuit.

Symptoms of P00B4 OBD II Trouble Code

  • Hard cold starts
  • Erratic idle
  • Engine stalling
  • Poor fuel mileage
  • Smoking exhaust
  • Fuel smell Symptoms
  • Erratic or false temperature readings
  • Poor engine performance

Common Causes of P00B4 OBD II Trouble Code

  • Defective radiator or other coolant temperature sensor (CTS)
  • Dirty/plugged sensor pickup
  • Sensor O-ring/Gasket leaking
  • Broken or damaged wiring harness
  • Fuse
  • ECM issue
  • Pin/connector problem (corrosion, melting, broken lock tab etc.)

Severity of P00B4 OBD II Trouble Code

This code would be considered a moderately severe issue. This will vary on what symptoms you have and how the fault is actually affecting your vehicles performance. The fact that the CTS's functionality directly influences the engine's air/fuel mixture, makes this an issue you do not want to leave unattended. Neglect this problem long enough, and you could be faced with some hefty engine repair bills.