Parts for your 2018 Mitsubishi Asx-Throttle position sensors

2018 Mitsubishi ASX throttle position sensor (TPS)

Yes — the 2018 Mitsubishi ASX uses a throttle position sensor, but it’s built into the electronic throttle body rather than being a separate bolt-on part. Technical sources that confirm this include Mitsubishi’s factory service information for the 2018 ASX/Outlander Sport, which details the Electronic Throttle Control system with a throttle actuator and dual-channel throttle position sensors integrated into the throttle body, the Mitsubishi EPC/ASA parts catalog, which lists the throttle body assembly as a single serviced unit with the TPS inside, and the model’s OBD-II diagnostic coverage, which includes TPS-related fault codes (e.g., P0121, P0122, P0123, P2135) that the manual attributes to the throttle valve position sensors.

• Mitsubishi Motors Service Manual (2018 ASX/Outlander Sport): Electronic Throttle Control system shows TPS built into the throttle body (main and sub tracks).
• Mitsubishi ASA/EPC parts catalog: Throttle body assembly includes the TPS, sensor not serviced separately.
• OBD-II DTC coverage: TPS/Throttle valve position sensor codes (P0121–P0123, P2135) documented for this model year/engine.

On the 2018 ASX, the TPS tells the engine computer exactly how far the throttle blade is open. Because it’s a drive-by-wire setup, the car uses an accelerator pedal position sensor at the pedal and a throttle position sensor in the throttle body to keep everything in sync. The ECU constantly cross‑checks both TPS tracks to manage idle, throttle response and emissions — if they disagree, it can drop the car into limp mode to protect the engine.

As part of regular servicing, the throttle body (and therefore the TPS) doesn’t need routine replacement, but it does benefit from a clean every 40–60,000 km, especially if the idle feels a bit rough or it’s hesitant off the line. Use a proper throttle body cleaner, avoid forcing the throttle blade by hand, and don’t flood the electronics. After any throttle body removal or replacement, organise a throttle/idle relearn with a scan tool — that’s the tidy way to get the ECU to recalibrate the new sensor tracks. If a scan tool isn’t handy, many workshops will perform this as a quick service task.

If the ASX shows a check engine light with codes like P0121–P0123 or P2135, or the idle hunts, surges or it suddenly lacks power, the TPS circuit could be the culprit. Because the TPS is integrated, the usual fix is to replace the complete throttle body assembly, inspect the connector and wiring under the bonnet, and update engine software if available. Use quality parts and correct torque on the clamp and mounting bolts, then complete the relearn. It’s a straightforward job for a pro, and it restores smooth throttle behaviour and reliable drivability.

Does the 2018 ASX have a separate TPS I can replace?

No. On this model the throttle position sensor is built into the throttle body as a dual-track unit. If the sensor fails or goes out of range, the usual repair is to replace the entire throttle body assembly and carry out a throttle/idle relearn.

What symptoms point to a failing TPS on a 2018 ASX?

Common clues include erratic or high idle, hesitation, flat spots, sudden limp mode, poor fuel economy and a check engine light. Typical stored fault codes are P0121, P0122, P0123 or P2135 relating to throttle position correlation or range.

Do I need to service the TPS during routine maintenance?

The sensor itself isn’t serviceable, but keeping the throttle body clean helps the TPS read accurately. Every 40–60,000 km, a careful clean and a quick scan for stored codes is smart. If the throttle body is replaced, a proper relearn procedure is recommended.