Parts for your 2003 Nissan Serena-Throttle position sensors

2003 Nissan Serena throttle-position-sensors (TPS) — what they do and how to look after them

Yes, the 2003 Nissan Serena does use throttle-position-sensors. Technical references including the Nissan Serena C24 Factory Service Manual (EC section: Throttle Control System), Nissan FAST parts catalog, and common diagnostic listings for DTCs P0120–P0124/P2135 confirm that the C24 Serena’s electronic throttle body contains dual throttle-position-sensors for feedback, with an accelerator pedal module carrying its own dual position sensors. On these models, the TPS is built into the throttle body and isn’t typically supplied as a separate standalone sensor.

On a 2003 Serena, the throttle-position-sensors tell the engine control module exactly how far the throttle plate is open. That info is critical for fuelling, ignition timing, idle control and even how the auto trans behaves under load. Being an electronic throttle (drive-by-wire), the Serena’s throttle body houses two TPS tracks for redundancy, so the ECM can cross-check signals for safety and accuracy.

If the TPS signals go out of whack, the Serena might hesitate off the lights, idle rough, surge, burn more fuel or drop into limp mode. You’ll often see the check engine light and codes like P0120–P0124 or P2135. Because the TPS is integrated, replacement usually means swapping the complete throttle body assembly rather than just a sensor.

• Common signs it’s time for attention:
  • Erratic idle or stalling when coming to a stop
  • Flat spots on acceleration or delayed throttle response
  • Unstable revs with A/C on or under electrical load
  • Check engine light with TPS-related fault codes

Servicing tips for a 2003 Serena throttle body/TPS setup:

• Rule out basics first: clean MAF, check for intake leaks, verify battery and charging system health, and inspect the throttle body connector and wiring for corrosion or broken pins.
• Clean the throttle bore and plate with a throttle-body safe cleaner. Don’t force the plate open by hand on an electronic unit.
• After cleaning or replacing the throttle body, carry out throttle closed-position learning and idle air volume learning with a capable scan tool, or follow the Nissan pedal dance if supported. Skipping this can leave the idle too high or low.
• If replacement is needed, use a new gasket, keep the bore spotless, and avoid overtightening the mounting bolts. Clear codes, do the relearn, then road test.

With the right checks and a proper relearn, most Serena throttle-position-sensor issues are sorted quickly and stay that way for years.

FAQs

Where is the TPS on a 2003 Nissan Serena?
The TPS is built into the electronic throttle body on the intake. You won’t find a separate external sensor on the side like older cable throttles. The accelerator pedal also has its own position sensors, but they’re a different component.

Can the TPS be replaced on its own, or is it a full throttle body job?
On most 2003 Serena engines (QR20DE/QR25DE and many YD22 variants), the TPS is non-serviceable by itself. The standard repair is to replace the complete throttle body, then perform a closed-throttle and idle air volume relearn with a scan tool.

Do I need a relearn after cleaning or replacing the throttle body?
Yes. Nissan specifies throttle valve closed-position learning and idle air volume learning after cleaning or replacement. Without it, idle quality and throttle response may be off, even if the hardware is fine.