1.DS 4 O2 sensor

Original part numbers and OE NO.
Upstream(Front) Oxygen Sensor part No.：DS4-O2-25​(for 1.6T EP6 engine, Bosch Replacement No. 1613C5)
Downstream(Rear) Oxygen Sensor part No.：DS4-O2-21​(with rapid heating, common to DS 7)
​​Defender Oxygen Sensor Fault Codes & Symptom Signs

P0134 (heating circuit break): common in hybrid systems with frequent start-stop caused by the aging of the wiring harness, need to measure the heating resistance (normal value of 4-6Ω) and replace the wiring harness.
P2270 (signal viscosity): ethanol gasoline sulfur pollution or fuel dilution triggered, it is recommended to use high grade fuel and clean the sensor probe.
P0420 (low efficiency of catalytic converter): carbon deposits on rear oxygen sensor or sintering of three-way catalytic converter, synchronized detection of front and rear oxygen signal curves is required.

​What causes & How to repair​

Frequent starting and stopping of the hybrid system: temperature fluctuations lead to cracking of the ceramic element, special temperature-resistant sensors (OE 1613C5) are required.
Urban short-distance commuting: low-speed driving leads to the accumulation of carbon deposits, it is recommended to use fuel additives (e.g., SIREP Original Liquid) every 20,000 kilometers.
Track driving: high speed leads to overheating of sensor, need to install heat dissipation shield.

​How much oxygen sensor cost to replace？
Original parts: 400-700 (150-250 for labor)
Secondary parts (Bosch/Denso): 250-450 (need to verify hybrid programming compatibility)

2.DS 5 O2 sensor

Original part numbers and OE NO.
Upstream(Front) Oxygen Sensor part No.: DS5-O2-HEV (for 1.6T plug-in engine with lead-resistant coating)
Downstream(Rear) Oxygen Sensor part No.: DS5-O2-TURBO (for diesel version, OE number common to DS 7)
​​Defender Oxygen Sensor Fault Codes & Symptom Signs

P061F (ECU logic error): abnormal mixture correction interferes with oxygen sensor signal, need to upgrade ECU software.
P0130 (Signal voltage abnormality): Carbon covered or fuel sulfide poisoning, suggest soaking and cleaning (cost 30-50).
P0037 (low voltage of heating circuit): Abnormal resistance of wiring harness in low temperature environment, need to replace the improved sensor with fast heating function.

​What causes & How to repair
Diesel version for use in cold areas: low temperatures cause delayed heating (requires replacement of Bosch 15733 series sensor).
Oil burning problem: oil vapors contaminate sensor probes, need to check piston ring sealing and replace with higher grade oil.
​How much oxygen sensor cost to replace？
Original parts: 450-800 (180-300 for labor)
Sub-factory parts (NTK/ACDelco): 300-550 (VIN verification of fitment required)

3.DS 7 SUV O2 sensor

Original part numbers and OE NO.
Upstream(Front) Oxygen Sensor part No.：DS7-O2-PHEV​(adaptable to plug-in version, high-temperature resistant ceramic design)
Downstream (Rear) Oxygen Sensor part No.: DS7-O2-HD (for 2.0T diesel engine, OE No. 1613D7)
​​Defender Oxygen Sensor Fault Codes & Symptom Signs
P0171/P0172 (mixture too lean/thick): Dirty MAF sensor or exhaust leak, clean intake system and check seals.
P0135 (Heating Circuit Failure): Oxidized wiring harness or ECU power supply abnormality, need to measure the voltage (standard 0.45V±0.1V).
​What causes & How to repair
Long distance towing: high loads cause sensors to overheat, it is recommended to check the exhaust system seals every 50,000 kilometers.
Luxury city driving: frequent start-stop accelerates carbon buildup, requiring a deep fuel system cleaning service (cost 50-80).
​How much oxygen sensor cost to replace？
Original parts: 500-900 (200-350 for labor)
Sub-factory parts: 350-650 (Bosch 15733 series recommended, compatibility to be verified by TecAlliance)
Generic recommendations and data validation

Part Number Verification: Verify compatibility by entering the VIN number through the DS EPC system or Bosch online catalog.
Diagnostic tool: Use DiagBox to read the oxygen sensor voltage waveform (normal range: 0.1-0.9V fluctuation for front oxygen, 0.2-0.6V stable for rear oxygen).
Cost optimization: Purchasing the sensor by yourself can save 20%-40% of the labor cost, but note that plug-in hybrid models need special programming.
(Note: The above prices may fluctuate ±15% due to regional and channel differences, real-time data suggest checking local dealers)

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