P0038

Code

LAND ROVER P — Powertrain

High Heated Oxygen Sensor Heater Control Circuit (bank 1 sensor 2)

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 14 EN: 49 RU: 47

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Page language: EN

Causes

Open or shorted wiring in the O2 heater circuit (short to battery voltage)
Failed or internally shorted oxygen sensor heater element
Corroded or loose connector or pins at the sensor or ECM
Poor ground or supply to heater circuit
Faulty PCM/ECM heater driver (internal short or failed transistor)
Aftermarket or incorrect sensor with different heater specs

Symptoms

MIL (Check Engine) lamp illuminated
Possible failed emissions test
Incomplete catalyst monitoring or readiness codes (downstream O2 heater important for diagnostics)
Usually no immediate driveability issues; engine may run normally

What to check

Read DTC and freeze frame data with scan tool; note conditions when code set
Visually inspect sensor, connector and wiring for damage, corrosion, pin push-out, or melted insulation
Backprobe and verify heater supply (12 V) and control/ground circuit behavior with ignition on/engine running
Measure heater element resistance at the sensor with sensor disconnected
Perform wiggle test on harness while monitoring heater circuit for intermittent faults
Verify related codes (other O2 or heater codes) and PCM wiring/ground integrity

Signal parameters

Heater supply voltage: typically battery voltage (~11–14 V) available to the heater circuit (varies by design)
Heater element resistance: typically low (example ~5–10 Ω for many sensors) — consult factory specification for exact value
Heater current: can be up to a few amps when active (depends on sensor design)
Control signal: ECM usually switches the heater to ground or modulates via PWM; when switched OFF the driver should not show battery voltage on control terminal

Diagnostic algorithm

Confirm code P0038 and note freeze-frame. Clear code and attempt to re-create; observe if code returns immediately or under specific conditions.
Visually inspect bank 1 sensor 2 harness and connector for corrosion, heat damage, water intrusion, or rodent damage; repair any obvious issues.
With ignition OFF, disconnect the sensor. Measure heater element resistance across the heater terminals at the sensor. Compare to factory spec. If open or out-of-spec (very low indicating short or very high/open), replace sensor.
With harness disconnected, check for battery voltage on the heater supply circuit with ignition ON (should have battery voltage or fused feed).
Backprobe the ECM/driver pin with ignition ON and engine running (or as required). Check for control behavior: when heater should be OFF, control terminal should not be stuck at battery voltage. If control terminal is at battery voltage (short to B+) the circuit is high.
If supply and sensor are OK but control behaves incorrectly, inspect wiring for shorts to battery (pinch points, especially near exhaust or suspension). Repair wiring as required.
If wiring and sensor check good and the control output at the ECM is still abnormal, test/replace the ECM only after verifying all wiring and loads. Consider using a known-good sensor or bench-tested replacement to confirm.
After repairs, erase codes, perform readiness/drive cycle and confirm the code does not return.

Likely causes

Corroded/contaminated sensor connector allowing high resistance or intermittent short
Damaged wiring rubbed through to battery voltage (short to B+) in harness near sensor
Heater element failed internally (short to heater supply)
ECM driver stage failed and is sourcing voltage when it should be off

Fault status

⚠️ Status

MIL ON — DTC stored. Heater circuit fault detected for HO2S bank 1 sensor 2; catalytic and O2 sensor diagnostics may be inhibited until repaired.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

Repair manuals

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P0038 — High Heated Oxygen Sensor Heater Control Circuit (bank 1 sensor 2)