P0140

Code

LAND ROVER P — Powertrain

O2 sensor circuit no activity detected (bank 1 sensor 2)

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 16 EN: 59 RU: 47

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Failed downstream O2 sensor (bank 1 sensor 2)
Open or short in O2 sensor signal circuit
Corroded, loose or damaged sensor connector or wiring harness
Heater circuit failure inside sensor or wiring fault (affects warm‑up and diagnostics)
Severe contamination or damage to sensor (oil, coolant, silicone, exhaust soot)
Exhaust leak near sensor or downstream that prevents expected readings

Symptoms

Check engine light (MIL) illuminated
Possible failed emissions test
Poor fuel economy if PCM reverts to default strategy
No noticeable engine driveability symptoms in many cases (downstream sensor monitors catalyst)
Possible stored related trouble codes (heater or upstream O2 codes)

What to check

Read and record freeze frame and all stored/ pending codes with a scan tool
Inspect sensor wiring and connector for corrosion, broken wires, pushed‑out pins, heat damage or contamination
Compare live data for bank 1 sensor 2 with bank 1 sensor 1 (upstream) while engine is warmed up
Check for related heater codes (P0141) or upstream codes (P0136–P0139)
Inspect exhaust near sensor for leaks, damage, or recent service that may have disturbed the connector

Signal parameters

Expected oxygen sensor output: ~0–1.0 V (narrowband) or switching activity; downstream (sensor 2) typically shows less rapid switching than upstream if catalyst is healthy
Heater circuit: low resistance to ground when measured at sensor connector (refer to OEM spec)
No open circuit between sensor signal and PCM pin; no short to voltage or ground
Live data should show a valid voltage value (not flat at 0.00 V or constant near rail)

Diagnostic algorithm

Verify the code and note freeze frame; check for multiple related codes
Visually inspect connector and wiring for damage, pin push‑outs, corrosion and repair as needed
With a scan tool, monitor bank 1 sensor 2 voltage and compare to bank 1 sensor 1 during various operating conditions (idle and light throttle)
Backprobe the sensor signal wire at the connector: confirm a varying voltage is present and not stuck at 0 V or constant value
Check continuity and resistance of signal and ground wires between sensor connector and PCM; check for short to battery positive or ground
Check heater circuit: measure heater resistance at the sensor connector (compare to spec) and energized voltage/ground to heater with key on/engine running; check heater fuse/relay/circuit
If wiring and power/ground are good but no signal, replace the sensor and clear codes
After replacement, perform drive cycle and confirm code does not return and sensor shows expected behavior
If new sensor also shows no activity and wiring/power/grounds test good, consider PCM/ground faults and consult OEM diagnostic procedure

Likely causes

Wiring connector corrosion at sensor (common on Land Rover due to weather)
Open signal or ground wire between sensor and PCM
Heater element open or shorted inside sensor or blown fuse/relay to heater circuit
Sensor failed from age or contamination (oil/coolant)
Previous exhaust work left connector disconnected or damaged

Fault status

⚠️ Status

O2 sensor circuit no activity detected (Bank 1 Sensor 2). PCM is not receiving a valid downstream oxygen sensor signal. Possible causes include failed sensor, open/shorted wiring, connector corrosion, heater circuit failure, contamination, exhaust leak or PCM fault.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Repair manuals

Manual library for LAND ROVER

320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

Send to email

P0140 — O2 sensor circuit no activity detected (bank 1 sensor 2)