Parts for your 2008 Honda Stream-Throttle position sensors

2008 Honda Stream throttle-position-sensor (TPS): what it does and how to look after it

Based on Honda technical references, the 2008 Honda Stream does use a throttle‑position sensor. The RN6–RN9 Stream (R18A 1.8L and R20A 2.0L i‑VTEC) runs electronic throttle control, and the TPS is built into the throttle body as a dual‑track sensor. This is documented in the Honda Stream (RN6–RN9) Service Manual’s Electronic Throttle Control section (with DTCs like P0121–P0123) and shown in the Honda Electronic Parts Catalogue where the throttle body assembly (e.g., 16400‑RNA‑A51 variants depending on engine/market) incorporates the sensor as a non‑serviceable component.

On the 2008 Honda Stream, the throttle‑position sensor tells the engine control module exactly how far the throttle plate is open. That live angle is the backbone for fuel delivery, ignition timing, transmission shift strategy, idle control and cruise control. Because it’s a drive‑by‑wire setup, the TPS works alongside the throttle actuator motor and the accelerator pedal position sensor to deliver smooth pedal feel and crisp response without a mechanical cable.

For owners, the sensor rarely needs attention by itself, but the throttle body it’s built into does appreciate periodic care. A light clean of the throttle bore and plate during a major service helps keep idle stable and throttle response sharp. Use throttle‑body‑safe cleaner, avoid soaking the external joints or connector, and don’t touch the factory stop screw. After cleaning or any battery disconnect, perform an idle learn so the ECU can recalibrate. Most technicians will warm the engine, turn off loads (A/C, lights), and allow it to idle for several minutes until the speed settles, or use a scan tool to run the throttle/idle relearn routine.

If the car shows a check‑engine light with codes like P0121/P0122/P0123, surging idle, flat spots on take‑off, poor fuel economy, or it drops into limp mode, it’s time for diagnosis. On this model, the TPS is integrated — replacement typically means fitting a complete throttle body with a new gasket, checking the harness and grounds, clearing codes, and carrying out the idle learn. Genuine or high‑quality OEM‑equivalent parts are the go‑to, and a scan tool that can view live data (throttle angle A/B correlation) makes quick work of confirming a fault.

• Typical service touchpoints: inspect connector and loom for corrosion or chafe, clean throttle bore and plate, verify idle learn after work under the bonnet.
• When replacement’s needed: fit complete throttle body, torque to spec, and relearn throttle/idle to restore smooth behaviour.

Popular questions about 2008 Honda Stream throttle-position-sensors

Does the 2008 Honda Stream actually have a TPS?
Yes. It’s built into the electronic throttle body as a dual‑track sensor. It isn’t a separate bolt‑on part like older cable‑throttle Hondas, so it’s monitored by the ECU and works with the throttle actuator motor.

Can the TPS be replaced on its own?
On this model, no. The sensor is integrated and not serviceable separately. If the TPS fails or the correlation goes out of spec, the usual repair is a complete throttle body replacement followed by an idle/throttle relearn.

How often should the throttle body/TPS be serviced?
There’s no fixed interval for TPS replacement. As part of routine servicing, a throttle body clean every 40,000–60,000 kilometres is a sensible idea, especially if the car mostly does short trips. Always perform an idle learn after cleaning or battery work.