Parts for your 1999 Daihatsu Gran move-Oxygen sensor

1999 Daihatsu Gran Move oxygen sensor

Based on technical references including the Daihatsu Pyzar/Gran Move workshop manual (EFI and emission control sections), the Daihatsu electronic parts catalogue, and application guides from OE sensor suppliers like Denso and NGK/NTK, the 1999 Daihatsu Gran Move runs a fuel‑injected petrol engine with a catalytic converter and a heated oxygen sensor (lambda sensor). In most markets it has an upstream HO2S in the exhaust manifold, some late-spec or stricter-emissions versions may also carry a post‑cat sensor. So yes, an oxygen sensor is fitted and it’s absolutely relevant to how this Gran Move runs and meets emissions rules.

On this model, the oxygen sensor constantly samples exhaust oxygen and helps the ECU trim fuelling in closed loop. That tightens up the air–fuel ratio around stoichiometric, so it burns cleaner, sips less fuel, and keeps the catalytic converter happy. When the sensor is tired or slow, the Gran Move can feel a bit doughy off the line, chew more petrol, and throw a check‑engine light with mixture or sensor performance codes.

As part of regular servicing, it’s smart to treat the oxygen sensor like a wear item. While there’s no strict replacement kilometre for every market, many technicians in Australia and New Zealand will inspect live data and replace the upstream sensor around 150,000–200,000 km if it’s sluggish. Signs it’s due include poor fuel economy, rough idle, blackened tailpipe, or fault codes related to O2 feedback. Always confirm with scan data: the upstream sensor should switch briskly once warm, lazy or flatlined signals are a giveaway.

When replacing, choose a quality, heated sensor suited to the Gran Move’s engine variant. A direct‑fit unit avoids splicing drama and ensures the heater circuit and connector are spot‑on. Let the exhaust cool, use penetrating oil on the threads, and crack it with the correct O2 socket. If the new sensor doesn’t come pre‑coated, apply a small amount of high‑temp, sensor‑safe anti‑seize to the threads only (never the tip). Torque it snug, route the harness clear of heat, and reset codes. It’s also worth checking for exhaust leaks upstream of the sensor, because leaks can trick the ECU and mimic a crook sensor. Do this and the 1999 Gran Move will stay smooth, efficient, and legal under the bonnet and out the tailpipe.

• How many oxygen sensors does a 1999 Daihatsu Gran Move have?
• What are the symptoms of a failing oxygen sensor on a Gran Move?
• Can a Gran Move be driven with a faulty oxygen sensor?

How many oxygen sensors does a 1999 Daihatsu Gran Move have?
Most 1999 Gran Move variants have one heated oxygen sensor before the catalytic converter. Certain later or stricter‑emissions versions may also have a second sensor after the cat for monitoring. A quick look at the exhaust and a scan of the ECU will confirm what’s fitted on the specific car.

What are the symptoms of a failing oxygen sensor on a Gran Move?
Common giveaways include higher fuel use, rough or hunting idle, hesitant throttle response, and a check‑engine light. Scan tools may show slow sensor switching or mixture codes. A sooty exhaust tip or fuel smell after cold starts can also point to a lazy sensor.

Can a Gran Move be driven with a faulty oxygen sensor?
It’ll usually run in open loop, but fuel economy will suffer and emissions will climb, which can shorten the catalytic converter’s life. It’s fine to get it home or to a workshop, but best to sort it promptly to avoid extra costs.