Parts for your 2020 Toyota Hilux-Oxygen sensor

2020 Toyota HiLux oxygen sensor: what’s fitted, what’s not

Based on Toyota’s service information (Repair Manual and Electrical Wiring Diagram for the AN120/AN130 series), the Electronic Parts Catalogue (EPC) for common 2020 HiLux model codes (e.g., GUN125/GUN126 diesels and TGN121 petrol), and the emissions hardware shown for ADR/Euro-compliant variants, the oxygen sensor story splits by engine type. Diesel 2020 HiLux models (2.8L 1GD‑FTV and 2.4L 2GD‑FTV) do not use a conventional oxygen/lambda sensor. Instead, they rely on a diesel particulate filter (DPF) with a differential pressure sensor and multiple exhaust gas temperature (EGT) sensors, plus MAF/MAP and EGR control. Some markets add NOx sensors where SCR is used, but that’s not an oxygen sensor. Petrol 2020 HiLux models (2.7L 2TR‑FE) are fitted with an upstream air‑fuel ratio (A/F) sensor and a downstream oxygen sensor for catalytic converter monitoring.

Why diesels in this range don’t run an O2 sensor comes down to how compression‑ignition engines operate. They typically run lean with excess air over a wide range, so traditional closed‑loop lambda control isn’t essential. Emissions compliance is achieved using EGR, precise injection control, and after‑treatment with the DPF monitored by EGT and differential pressure sensors. That’s exactly what Toyota’s wiring diagrams and parts listings show for the 2020 HiLux diesels.

For petrol 2020 HiLux owners, the oxygen sensor hardware matters. The upstream A/F sensor constantly measures oxygen content in the exhaust to keep the mixture right on the money, helping the engine deliver good fuel economy and smooth running while protecting the catalytic converter. The downstream O2 sensor checks how well the cat is doing its job. If either sensor drifts with age or gets contaminated (silicone sealants, coolant, oil vapour), the ECU has to work harder, trims head off, and fuel use can creep up. It can also throw a check‑engine light and log codes for slow response or heater faults.

There’s no fixed replacement interval in Toyota schedules, but many techs see performance tail off somewhere after 160,000–200,000 km. During routine servicing, it’s smart to scan fuel trims, confirm the A/F sensor is switching/responding as expected, and check for exhaust leaks ahead of the sensors (a tiny leak can fake a lean reading). If a sensor needs replacing, go for OE‑grade (Denso is typical), match the connector exactly, and avoid universal splicing on late‑model cars. Always fit to a cold exhaust, don’t touch the tip, and torque to spec with a dab of appropriate anti‑seize if the part doesn’t come pre‑coated. After installation, clear codes, perform an ECU readiness drive, and recheck trims. Keeping the engine tight—no vacuum leaks, clean MAF, healthy ignition—helps sensors live longer. If the ute sees lots of short trips, an occasional longer run at operating temp helps keep the cat and sensors happy.

• Common signs it’s time: higher fuel use, rough idle, sulphury exhaust smell, failed WOF/rego emissions test, or codes like P0130–P0161.
• Good practices: fix exhaust leaks, use the correct sealants, and keep up with air filter and MAF cleaning as needed.

Bottom line: 2020 HiLux diesels don’t use an oxygen sensor, petrol variants do, with an upstream A/F sensor and a downstream O2 sensor that deserve occasional attention to keep the ute running sweet and efficient.

Popular questions

Does a 2020 HiLux diesel have an oxygen sensor?

No. The 1GD‑FTV and 2GD‑FTV diesels use a DPF with differential pressure and multiple EGT sensors, plus EGR, MAF and MAP for control. Some markets add NOx sensors with SCR, but that’s different to an oxygen sensor.

How many oxygen sensors are on a 2020 HiLux petrol and where are they?

Two. An upstream air‑fuel ratio (A/F) sensor sits in the exhaust manifold before the catalytic converter, and a downstream O2 sensor sits after the cat to monitor its efficiency.

When should the HiLux petrol oxygen sensor be replaced?

There’s no fixed interval, but many are refreshed after 160,000–200,000 km or when fuel trims drift, a check‑engine light appears, or emissions/driveability slip. Always confirm with scan data and basic exhaust leak checks.