Parts for your 2016 Toyota Bb-Temperature sensors

2016 Toyota bB temperature sensors: what they do and how to look after them

Temperature sensors are absolutely used on the 2016 Toyota bB. Technical references including the Toyota bB QNC20/QNC21 Workshop Manual (Engine Control for 1NZ‑FE and 2SZ‑FE), the Toyota Electrical Wiring Diagram for the bB platform, and DENSO engine coolant temperature (ECT) sensor specifications all detail multiple temperature inputs feeding the engine control module and HVAC systems. These include the ECT sensor, the intake air temperature (IAT) sensor (often integrated with the MAF), ambient air temperature for the air‑con, and an automatic transmission fluid temperature sensor on models with the 4‑speed auto.

On this bB, these sensors are the quiet achievers: they handle cold‑start enrichment, set idle speed, trim fuel and ignition as conditions change, switch the radiator fans, protect the engine from overheating, refine air‑con performance, and help the auto shift at the right time. If one goes out of whack, the dash light can pop on, the fans may run constantly, it can drink more fuel, or it may start poorly on a cold Kiwi morning or Aussie arvo.

There’s no fixed replacement interval for temperature sensors, but they’re worth checking during routine servicing. Keeping the coolant fresh (as per Toyota’s Super Long Life Coolant schedule) helps prevent corrosion that can skew readings. Make sure connectors are clean, clips intact, and wiring isn’t rubbed through under the bonnet.

• Common signs of trouble: hard cold starts, rich running, high or hunting idle, weak heater performance, poor economy, and OBD‑II codes like P0115–P0119 (ECT) or P0110–P0113 (IAT).
• Smart maintenance: clean the MAF/IAT with proper MAF cleaner (never brake/carby cleaner), inspect the ambient temp sensor behind the grille after any front‑end knock, and verify ECT readings with a scan tool on a cold start (they should match ambient).

Replacing an ECT sensor is usually straightforward: let the engine cool, disconnect the battery, drain a little coolant, unplug the connector, and swap the sensor on the thermostat housing or cylinder head (location varies by engine). Use a new O‑ring/seal, avoid thread tape unless specified, and tighten to the workshop manual spec. Refill with the correct pink Toyota SLLC, bleed air, then confirm no leaks and that live data looks right. A quick road test and fan‑cycle check, and you’re good for many more kilometres with no dramas.

Popular questions

Where is the coolant temperature sensor on a 2016 Toyota bB?
It’s typically fitted in the coolant outlet near the thermostat housing or on the cylinder head water jacket. On the 1NZ‑FE and 2SZ‑FE used in the bB, that spot is at the front or end of the head where the coolant exits. Space is tight on some models, so a mirror and a small ratchet help. If unsure, confirm the exact location in the Toyota workshop manual or the vehicle’s EWD.

Can you keep driving with a faulty temperature sensor?
You might be able to limp it, but it’s not a great idea. The ECU can drop into failsafe, fuelling goes richer, fans can run full‑time, and overheat protection may not kick in correctly. That can cost you a head gasket. Best to book it in soon and get a proper scan and fix.

Do temperature sensors need regular replacement?
Not on a time basis. Replace only if testing shows they’re out of spec or they’ve set a fault code. What does help is preventative care: keep the correct coolant fresh per Toyota’s schedule (often up to 160,000 km/10 years initial, then 80,000 km/5 years—check your handbook), maintain clean electrical connections, and ensure the MAF/IAT isn’t contaminated.