Parts for your 2000 Holden Commodore-Throttle position sensors

2000 Holden Commodore throttle position sensor (TPS) — what it does and how to look after it

Based on technical references including the Holden VT/VX Series Factory Service Manual (Engine Controls), GM Powertrain service information for the 3.8L Ecotec V6 (L36) and 5.7L Gen III V8 (LS1), and ACDelco/Delphi parts catalogues for VT–VX applications, the 2000 Holden Commodore is fitted with a throttle position sensor (TPS) on both V6 and V8 variants. It’s a three‑wire potentiometer mounted to the throttle body that reports throttle angle to the powertrain control module (PCM).

The TPS tells the PCM exactly how far the driver’s foot has opened the throttle. That live signal is crucial for fuelling, spark timing, idle control, EGR strategy (where fitted), and even the 4L60‑E auto’s shift behaviour and kick‑down logic. At closed throttle, the TPS sits near about half a volt, ramping smoothly up towards roughly 4.5 volts at wide‑open throttle, the PCM watches the sweep for accuracy and consistency.

When a TPS wears out, gets contaminated, or loses a clean signal due to wiring issues, the Commodore can show annoying habits: a surging or hunting idle, flat spots off the line, random stalling when coming to a stop, harsh or late shifts, poor fuel economy, and a check‑engine lamp. Common fault codes include P0121 (range/performance), P0122 (low input), and P0123 (high input).

Good servicing practice for a 2000 Commodore includes a quick TPS check whenever the throttle body is cleaned or the idle’s a bit crook. Don’t drown the sensor in cleaner—sprays can wick past seals—clean the throttle plate and bore only. Inspect the TPS connector for green crusties or looseness and the harness for chafing near the throttle body. With a scan tool, confirm the throttle percentage moves smoothly from closed to wide‑open without spikes, with a multimeter back‑probe, you’re looking for a steady voltage sweep.

Replacement is straightforward on both Ecotec and LS1 throttle bodies and the TPS is non‑adjustable on these models. Recommended approach:

• Disconnect the battery.
• Unplug the TPS and remove the two retaining screws.
• Transfer the new sensor, ensuring the drive tang engages, nip the screws up snug (about 2–3 N·m—do not over‑tighten).
• Reconnect, then perform an idle learn: key ON for ~10 seconds, key OFF for ~10 seconds, start and let it idle until warm, a scan tool idle learn is even better.

Choose a quality sensor (ACDelco/Delphi or a reputable equivalent) to avoid drivability dramas. With a clean throttle body, good wiring, and a healthy TPS, a 2000 Commodore will idle cleanly, shift smartly, and feel crisp underfoot.

Popular questions about 2000 Holden Commodore throttle position sensors

Where is the TPS on a 2000 Commodore?
It’s bolted to the side of the throttle body under the bonnet. On the 3.8L Ecotec V6 it faces the front/side with a three‑pin plug, on the 5.7L LS1 V8 it’s similarly mounted to the throttle body near the throttle cable quadrant.

The part is external and easy to see once the intake duct is off.

Do I need to calibrate a new TPS on this model?
No manual adjustment is required—the sensor is non‑adjustable. After fitting, perform a basic idle learn (key‑on/key‑off, then warm idle) or use a scan tool to run the PCM’s throttle/idle relearn so the readings settle quickly.

If throttle percentage looks odd after replacement, check the connector and ensure the tang is correctly engaged.

What symptoms and fault codes point to a bad TPS?
Tell‑tales include a hunting idle, flat spots when taking off, harsh or late auto shifts, erratic kick‑down, stalling when coasting to a stop, and higher fuel use. The check‑engine light may appear.

Typical codes are P0121 (TPS performance), P0122 (low input), and P0123 (high input). A smooth voltage sweep test or scan‑tool throttle trace will confirm it.