Parts for your 2004 Toyota Bb-Throttle position sensors

2004 Toyota bB Throttle Position Sensor (TPS): what it does and how to look after it

Yes, the 2004 Toyota bB uses a throttle position sensor. Toyota’s technical literature for the NCP30/31/35 bB series (1NZ-FE 1.5L and 2NZ-FE 1.3L) describes an Electronic Throttle Control System (ETCS-i) with a dual-track throttle position sensor integrated into the throttle body, outputting VTA/VTA2 signals to the ECM. This is detailed in Toyota New Car Features (NCF) for the NCP3# platform and the Toyota Repair Manual SFI/Engine Control sections, and is backed up by the Toyota Electronic Parts Catalog, which lists a sensor within the throttle body assembly for 2004 bB variants. On some cable-throttle derivatives, the TPS is a bolt-on unit at the throttle shaft, ETCS-i variants have the sensor built into the throttle body and it’s not serviced separately.

On the 2004 Toyota bB, the TPS tells the engine computer exactly how far the throttle plate is open. That real-time angle is used to fine-tune fuel delivery, ignition timing, idle control and, on automatics, shift behaviour. When it’s healthy, throttle response feels crisp and consistent, when it’s crook, drivers may notice flat spots, a hunting idle, stalling when coming to a stop, harsh shifts, or the MIL on with codes like P0120–P0123, P0220 or P2135.

Maintenance-wise, there’s no scheduled replacement for the throttle-position-sensor, but it pays to:

• Keep the throttle body clean using a throttle-safe cleaner. Avoid soaking the sensor area and never wind the factory stop screw.
• Inspect the TPS connector for oil ingress or green crusties (corrosion). Clean and reseat as needed.
• Scan live data for VTA/VTA2. At closed throttle you’ll typically see roughly 0.6–0.8 V, rising smoothly to about 3.8–4.5 V at wide-open throttle with no dropouts or spikes.

Replacement advice depends on which bB they’ve got:

• ETCS-i (drive-by-wire): the TPS is integral to the throttle body. Replace the throttle body assembly, fit a new gasket, and perform a throttle/idle learn with a scan tool (or battery-off then warm idle relearn). Don’t try to pry off the sensor—it's not designed to be serviced separately.
• Cable-throttle: the TPS can usually be replaced on its own. Mark the old position, swap the sensor, and set the base voltage/angle with a scan tool. Some procedures call for a feeler gauge at the throttle stop to set the switch-on point—follow the Toyota repair manual steps.

A quality OEM or OE-equivalent part is worth it—cheap copies can drift out of spec and cause ETCS-i failsafes. After any work, clear codes, confirm smooth live-data traces, and take it for a gentle run to let the ECM settle. Easy as—and no worries on the next WOF or rego check.

Popular questions about 2004 Toyota bB throttle-position-sensors

Does a 2004 Toyota bB actually have a TPS?
It does. Toyota’s NCF and Repair Manual for the NCP30/31/35 series show a throttle position sensor on all engines—either integrated into the ETCS-i throttle body or as a bolt-on unit on cable-throttle versions. The Electronic Parts Catalog also lists the sensor within the throttle body assembly for 2004 models.

What fault codes point to a bad TPS on a bB?
Common codes include P0120–P0123 (TPS circuit range/performance/low/high), P0220-series for the second track on dual sensors, and P2135 for correlation between the two tracks. If you see these with symptoms like surging or limp mode, check the connector and wiring first, then verify smooth VTA/VTA2 traces before replacing parts.

Can a DIYer replace or calibrate the TPS on this model?
Yes, but it depends on the throttle type. On ETCS-i, the sensor is built into the throttle body—replace the assembly and run a throttle/idle learn with a scan tool. On cable-throttle units, a DIYer can swap the sensor and set the base angle/voltage with a scan tool following the Toyota procedure. Avoid touching the stop screw and don’t overtighten the small screws.