Parts for your 2008 Mitsubishi Lancer-Throttle position sensors

2008 Mitsubishi Lancer throttle position sensor: what it does and how to look after it

Based on the Mitsubishi Motors workshop manual for the 2008 Lancer (CJ, 4B11/4B12) and OEM parts catalogues, this model uses electronic throttle control with two throttle position sensors (main and sub) integrated into the throttle body, plus an accelerator pedal position sensor. The TPS isn’t a separate, adjustable item, it’s built into the throttle body assembly and monitored by the engine ECU. So yes—throttle position sensors are fitted and very relevant on a 2008 Mitsubishi Lancer.

In this Lancer, the throttle position sensors tell the ECU exactly where the throttle plate is, so it can manage fuel, spark and idle speed. With drive-by-wire, the ECU compares the pedal position with the throttle position to keep things safe and smooth. If the signals don’t agree, it can drop into limp mode to protect the engine and you.

As part of regular servicing, the TPS itself isn’t a routine replacement, but the throttle body should be inspected and kept clean. A light clean of the throttle bore and plate (without flooding the shaft area) every 60,000–100,000 kilometres helps prevent sticky throttle behaviour. Don’t force the plate open by hand—use the key-on position if needed, and go easy with cleaner to avoid damaging the sensors.

• Common symptoms of TPS/throttle body issues: erratic idle, flat spots, poor fuel economy, stalling, or the check engine light with codes like P0121–P0123 or P2135.
• Diagnosis: use a scan tool to view throttle angle (main/sub) and pedal angle, look for smooth, matching movement and proper correlation.
• Replacement: because the TPS is integrated, the fix is typically a new throttle body assembly. Fit a new gasket, check hoses and clamps, and don’t overtighten. Many CJ Lancers need a throttle/idle relearn with a scan tool after replacement or a battery disconnect.
• Electrical checks: inspect the connector for corrosion or moisture, confirm good earths, and test for 5 V reference.
• Parts choice: quality OEM-equivalent throttle bodies tend to give the best long-term results and fewer calibration dramas.

Look after the throttle body and its sensors, and the 2008 Lancer will keep its smooth tip-in and tidy idle without any fuss.

Popular questions

Does a 2008 Mitsubishi Lancer have a separate throttle position sensor?
Yes, it has throttle position sensing, but it’s integrated into the electronic throttle body as dual sensors (main/sub). There’s no separate, adjustable TPS like on older cable-throttle setups. The accelerator pedal also has its own position sensor.

Can the TPS be adjusted on a CJ Lancer?
No. The TPS is non-adjustable. If the sensor fails or drifts out of range, the correct repair is to replace the throttle body assembly and carry out a throttle/idle relearn with a suitable scan tool.

Is it safe to drive with a TPS fault code?
Short distances may be possible, but the car can enter limp mode, hesitate, or stall. It’s best to address it promptly—check wiring and connector condition, then repair or replace the throttle body as required and clear codes after relearn.