Parts for your 2018 Honda Odyssey-Throttle position sensors

2018 Honda Odyssey throttle position sensors — what they do and how they’re serviced

Based on Honda’s 2018 Odyssey (RL6) service information for the Electronic Throttle Control system and the factory DTC chart (including P0121, P0122, P0123 and P2135), this model absolutely uses throttle position sensors. They’re built into the electronic throttle body as dual, redundant sensors that report actual throttle plate angle to the PCM. The accelerator pedal has its own separate position sensors, but those don’t replace the throttle position sensors on the throttle body.

On a 2018 Odyssey with the J35 V6 and drive‑by‑wire, the throttle position sensors (often listed as TP Sensor A and TP Sensor B) let the engine computer compare commanded throttle against the real plate position. That keeps the V6 smooth, responsive and safe, if the two signals disagree, the PCM can drop the vehicle into limp mode and light the MIL, which is why those DTCs exist in the Honda diagnostic tree. Honda service manuals and technical bulletins also note these sensors are part of the throttle body assembly, not a loose, bolt‑on item.

For servicing, the throttle body is the bit to eye off. The TP sensors are not generally sold separately from the electronic throttle body on late‑model Hondas. If a TP sensor fault is confirmed after basic checks, the usual fix is replacing the throttle body assembly, fitting a fresh gasket, and performing the PCM throttle/idle learn. For light maintenance, a careful clean of the throttle bore and plate with a proper throttle‑body cleaner can sort rough idle or sticky response, but never force the plate open by hand — on this system the motor and gears can be damaged.

• Common signs of TP sensor trouble: MIL on, poor throttle response, surging idle, limp mode, and codes like P0121–P0123 or P2135.
• Before replacement: inspect the connector, check for water ingress or corrosion, verify 5V reference and ground, and confirm live data for TP Sensor A/B tracks smoothly and agrees.
• After any throttle body work: do an idle relearn with a scan tool or follow Honda’s key‑on/warm‑up procedure from the service manual to stabilise idle.

Keeping the intake tract clean, ensuring the air filter isn’t choked, and sorting any vacuum leaks will help the throttle body and its sensors live a long life. For most owners, inspection during regular servicing and only intervening when symptoms or codes appear is the sensible Aussie/Kiwi way.

Popular questions

Does the 2018 Honda Odyssey have a separate, replaceable throttle position sensor?
On this model the TP sensors are integrated into the electronic throttle body. Honda’s parts catalogues and service procedures specify replacing the complete throttle body if sensor faults are confirmed, followed by an idle/throttle learn. A standalone TPS isn’t typically supplied.

What’s the best way to clean the throttle body without upsetting the sensors?
With the battery disconnected and the intake duct removed, spray a throttle‑safe cleaner on a cloth and wipe the bore and plate gently. Don’t wedge or force the plate open and don’t flood the electronics. Reassemble with the duct snug and perform an idle relearn so the PCM can recalibrate.

Which fault codes point to throttle position sensor issues on a 2018 Odyssey?
Honda’s diagnostic list flags TP sensor faults with P0121, P0122, P0123 and correlation codes like P2135. These prompt checks of the throttle body’s dual sensors, wiring, 5V reference, and ground, along with a comparison of TP Sensor A/B signals in live data.