Parts for your 2018 Toyota C-hr-Oxygen sensor

2018 Toyota C‑HR oxygen sensor: what it does and when to replace it

Based on technical sources, oxygen sensors are absolutely used on the 2018 Toyota C‑HR. Toyota’s factory service information (TIS/repair manual) and the Toyota Electronic Parts Catalogue specify an upstream air‑fuel ratio (A/F, wideband) sensor at Bank 1 Sensor 1 and a downstream oxygen sensor at Bank 1 Sensor 2 in the exhaust stream. Modern emissions and OBD‑II requirements (e.g., SAE J1979 and ADR 79/04 Euro 5 compliance for petrol vehicles sold in Australia and New Zealand) rely on these sensors for closed‑loop fuelling and catalyst monitoring. So yes—this model is fitted with oxygen/air‑fuel sensors and they’re relevant to performance, economy, and emissions.

For the 2018 Toyota C‑HR, the oxygen sensor setup does a lot of heavy lifting. The upstream A/F (lambda) sensor constantly measures oxygen content in the exhaust so the engine computer can fine‑tune fuelling and keep the mixture bang‑on for smooth running and great fuel economy. The downstream oxygen sensor sits after the catalytic converter, checking that the cat is doing its job. Together they help the C‑HR run cleaner, sip fewer litres per 100 km, and sail through WOF or rego checks.

While Toyota doesn’t list a fixed replacement interval, these sensors age. On high‑kilometre cars, a tired A/F sensor can respond slower, nudging up fuel use and sometimes triggering the check‑engine light. Many workshops in Aus and NZ will proactively replace the upstream sensor somewhere around 160,000–200,000 km, and the downstream unit as needed based on diagnostics or catalyst efficiency codes.

• Typical symptoms of a crook sensor: higher fuel consumption, rough idle, flat spots on acceleration, exhaust smell, failed emissions, or a check‑engine light (often P013x/P014x range DTCs).
• Good servicing habits: scan live data for fuel trims and A/F sensor response, confirm heater circuit operation, inspect wiring and connectors for heat damage, and check for intake or exhaust leaks that can skew readings.
• Replacement tips: stick with the correct Toyota/Denso‑spec sensor, avoid contamination from silicone sprays or coolant/oil leaks, and don’t overtighten—use the service manual torque and an O2 socket. Many genuine sensors come pre‑coated, if not, use O2‑safe anti‑seize only on the threads. After fitting, clear codes and complete a proper drive cycle so OBD readiness sets.

Across common AU/NZ C‑HR variants (1.2‑litre turbo petrol, 2.0‑litre petrol, and hybrid), you’ll typically find one A/F sensor before the cat and one O2 sensor after it. Access can be from underneath, use stands or a hoist for safety.

How many oxygen sensors does a 2018 Toyota C‑HR have?

Most 2018 C‑HR petrol and hybrid variants have two sensors on Bank 1: an upstream air‑fuel ratio (wideband) sensor before the catalytic converter and a downstream oxygen sensor after it. The pair handles fuel control and catalyst monitoring, which is required for OBD‑II and local emissions compliance.

When should the oxygen sensor be replaced on a C‑HR?

There’s no fixed schedule from Toyota, but many technicians replace the upstream A/F sensor proactively around 160,000–200,000 km if fuel economy drops or response slows. Otherwise, replace any sensor that sets a related DTC, fails a diagnostic test, or shows sluggish readings on a scan tool.

Can it be driven with a faulty oxygen sensor?

Usually the car will still run, but it may use more fuel, feel a bit doughy, and risk damaging the catalytic converter. It can also fail a WOF/regulatory emissions check. Best bet: diagnose and sort it promptly to protect the cat and keep running costs in check.