Parts for your 1998 Daihatsu Gran move-Oxygen sensor

1998 Daihatsu Gran Move oxygen sensor: what it does, where it is, and when to replace it

Based on technical references — including the Daihatsu Pyzar/Gran Move workshop manual (EFI section: Heated Oxygen Sensor/HO2S) and AU/NZ application catalogues from DENSO and NGK/NTK — the 1998 Daihatsu Gran Move is fitted with a heated oxygen sensor. As an EFI petrol model designed to meet period emissions rules with a catalytic converter, it runs closed-loop fuelling using an O2 sensor positioned in the exhaust stream.

On this Gran Move, the oxygen sensor’s job is to read how much oxygen is in the exhaust and send that info to the ECU. The ECU then trims the air–fuel mix so the engine stays right on the sweet spot for economy, drivability, and keeping the cat happy. When the sensor gets lazy with age or fouling, the ECU has to guess, fuel use goes up, and performance can feel a bit doughy. It’s usually a 4‑wire heated type mounted in the exhaust manifold or front pipe, with some markets also getting a second (post‑cat) sensor to monitor catalytic converter efficiency.

• Common signs it needs attention: higher fuel consumption, rough idle, sulphury exhaust smell, hesitation, failed emissions, or a check‑engine light (typical OBD‑II codes like P0130–P0135/P0141).
• Lifespan: many HO2S units deliver reliable service for 100,000–160,000 kilometres. By that sort of distance, testing or proactive replacement is sensible, especially if economy has slipped.
• Best practice at service time: scan for stored codes and live sensor response, inspect the sensor harness and plug for heat or abrasion damage, and check for exhaust leaks ahead of the cat (leaks can skew readings).

When replacing, choose an OEM‑quality unit from the major sensor suppliers that list the 1998 Gran Move/Pyzar. Let the exhaust cool, soak the old sensor thread with penetrant, and use an O2‑sensor socket. Most new sensors come pre‑coated, if so, don’t add extra anti‑seize. Route the lead away from the exhaust and secure the connector so it can’t rub. After fitting, clear fault codes and verify the sensor switches promptly once warm. Getting the oxygen sensor sorted keeps the Gran Move running crisply, saves petrol on the school run, and protects the catalytic converter from rich running.

Popular questions

Where is the oxygen sensor on a 1998 Daihatsu Gran Move?
It’s typically threaded into the exhaust manifold or the front section of the exhaust under the bonnet, with a 4‑wire plug leading to the engine loom. Some markets may also have a second sensor mounted after the cat under the car.

How often should the oxygen sensor be replaced?
There’s no strict interval, but checking it around 100,000–160,000 kilometres is smart. Replace if it’s slow to respond, has fault codes, or fuel economy and drivability have dropped despite a good basic tune.

Is it OK to drive with a faulty oxygen sensor?
It’ll usually run, but the ECU may go open‑loop and over‑fuel. That means higher petrol use, more emissions, and potential long‑term damage to the catalytic converter. Best to sort it sooner rather than later.