Error code

OBD2 P0038

OBD2P0038
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

HO2S Heater Control Circuit High.

Severity

moderateCan drive, but symptoms may affect performance and fuel efficiency.

Summary

P0038 indicates an issue with the heater control circuit of the heated oxygen sensor (HO2S) 2 on bank 1, which is located after the catalytic converter.

Symptoms

  • Rich-running condition
  • Lean-running condition
  • Increased fuel consumption
  • Loss of power
  • Rough idling
  • Visible black smoke from tail pipe
  • Hard starting in some cases
  • Illuminated CHECK ENGINE light

Common Causes

  • Burnt wiring caused by proximity to hot exhaust components
  • Short circuits due to burnt wiring
  • Corrosion or impact damage on connectors
  • Bad ground connections
  • Blown fuses in the heater control circuit

Diagnosis

  1. Perform a visual inspection of wiring and connectors for damage.
  2. Check fuses in the heater control circuit.
  3. Test continuity and resistance of sensor wiring.
  4. Inspect oxygen sensor element for discoloration or deposits.
  5. Replace faulty components as needed and retest.

Fixes

  • Replace damaged wiring, connectors, or blown fuses in the heater control circuit.
  • Replace the oxygen sensor if it is defective or has deposits.

FAQ

What does P0038 mean?

P0038 indicates a high input voltage issue in the heater control circuit of HO2S 2 on bank 1.

How do I diagnose P0038?

Start with visual inspections and electrical tests to identify faulty wiring or components.

View source

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

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