Parts for your 2009 Honda Elysion-Throttle position sensors

2009 Honda Elysion throttle-position-sensors: what they do and when to service them

Based on Honda technical literature and parts listings, the 2009 Honda Elysion is fitted with throttle-position-sensors. Honda’s Electronic Throttle Control System (ETCS) used on the K24A four-cylinder and J-series V6 engines employs dual throttle position sensors (TP Sensor A and TP Sensor B) built into the throttle body. This configuration is detailed in Honda factory service manuals for the period, the Honda Elysion RR-series electronic parts catalogue (which shows the TP sensor integrated with the throttle body assembly), and the Honda diagnostic trouble code coverage for TP circuits (e.g., P0121, P0122, P0221) in workshop manuals. The vehicle also uses an accelerator pedal position (APP) sensor at the pedal, but that’s separate from the throttle body’s TP sensors.

On the 2009 Honda Elysion, the throttle-position-sensors constantly report the throttle plate angle to the engine control unit. The ECU compares the two signals (A/B) for accuracy, then adjusts fuel, ignition timing, transmission shift logic and cruise control. It’s a safety-critical, drive-by-wire setup, so redundancy is the name of the game: if one signal goes out of range, the ECU can drop into limp mode to protect the engine and passengers.

As part of regular servicing, there’s no set interval to replace the throttle-position-sensors. What owners should do is keep the throttle body clean and the connectors healthy. Under the bonnet, check the harness for chafing or oil contamination, and make sure the connector pins aren’t corroded. If the Elysion shows symptoms like erratic idle, hesitation, sudden surging, poor economy, or a check engine light with TP-related codes (P0120–P0123, P0220–P0223), it’s time for proper diagnosis with a scan tool—look at live data for TP% agreement between Sensor A and B, and compare with APP readings.

For this model, the throttle-position-sensors are typically integrated into the throttle body and aren’t a separate, adjustable item. If the sensor fails, most workshops will replace the throttle body assembly and its gasket, then perform an idle learn/throttle angle relearn. After fitting, ensure coolant hoses (if fitted) are clamped correctly, bolts are torqued to spec, and no vacuum leaks are introduced. The relearn generally involves resetting the ECU’s learned values, warming the engine, and letting it idle with all accessories off for several minutes. When cleaning, use proper throttle body cleaner, avoid flooding the sensor area, and don’t force the throttle plate by hand. A careful approach here saves headaches down the road and keeps the Elysion running sweet as at Aussie and Kiwi cruising speeds.

• Common signs of trouble: CEL on, limp mode, idle hunting, throttle lag, mismatched TP A/B readings.
• Best practice: clean throttle body every 40–60,000 kilometres or when deposits are visible, inspect wiring at each major service.
• Parts tip: use quality gaskets and genuine-spec throttle bodies to avoid drivability gremlins.

FAQs

Does the 2009 Honda Elysion have a throttle-position sensor or is it only at the pedal?
It has both. The pedal houses the accelerator pedal position (APP) sensor, while the throttle body itself contains dual throttle-position-sensors (A and B). The ECU cross-checks them for accuracy as part of the drive-by-wire system.

Can the throttle-position sensor be replaced on its own?
On most 2009 Elysion variants, the TP sensors are integrated into the throttle body and aren’t serviced separately. While some aftermarket options claim standalone sensors, Honda service procedures generally call for replacing the entire throttle body if the sensor set fails or is out of spec.

Do I need an idle relearn after cleaning or replacing the throttle body?
Yes. After cleaning or replacement, perform the idle/throttle angle relearn so the ECU can recalibrate. Typically that means clearing learned values, warming the engine fully, switching off all loads (A/C, lights), and letting it idle undisturbed for several minutes.