Parts for your 1998 Mitsubishi Pajero-Throttle position sensors

1998 Mitsubishi Pajero throttle position sensor (TPS)

Based on Mitsubishi’s factory service information for the 1997–1999 Pajero/Montero range and the Mitsubishi ASA/CAPS parts catalogue (engine electrical and fuel/air sections), the 1998 Mitsubishi Pajero is fitted with a throttle position sensor. Petrol EFI engines (6G72 3.0L and 6G74 3.5L) use a TPS on the throttle body, and the 2.8L turbo-diesel 4M40 uses a throttle/accelerator position sensor for ECU control of EGR and timing. Service manuals and parts listings (e.g., TPS part families used across V20 Pajero) confirm the sensor’s presence and role.

The TPS tells the engine control unit how far the throttle is opened. On petrol Pajeros it manages fuelling, ignition timing, idle quality, and kickdown/shift behaviour on autos. On the 4M40 diesel it doesn’t meter air like a petrol throttle, but the ECU still uses the signal to fine-tune EGR, idle-up, and injection pump control for smoother drivability. When the TPS goes out of spec, owners often notice a flat spot on take-off, hunting idle, higher fuel use, or abrupt gear changes.

As part of regular servicing, it’s smart to check the TPS every 40–60,000 km or whenever the throttle body is cleaned. A quick visual once-over for cracked plugs, frayed wiring at the connector, or moisture in the loom is worthwhile. With a multimeter or scan tool, verify the closed-throttle voltage sits around the factory spec (typically about 0.5 V on petrol models) and rises smoothly to roughly 4.5 V at wide open. Any drop-outs or spikes mean it’s time to replace. On some Pajero variants the idle switch is integrated with the TPS, confirm the idle contact engages at closed throttle per service data.

Replacement is straightforward: key off, unplug the connector, remove the two retaining screws, swap the sensor, then set the base position. Back-probe the signal wire to dial in the closed-throttle voltage while gently rotating the sensor before tightening the screws. Recheck idle speed, clear any fault codes, and take a short drive so the ECU can relearn. Use a quality OEM-equivalent sensor suited to your engine code.

To keep the TPS happy longer, avoid blasting the throttle body area with high-pressure water, keep the throttle plate clean (use throttle-safe cleaner), and ensure the accelerator cable isn’t over-tight, which can hold the throttle slightly open and skew the reading.

• Common symptoms: erratic idle, hesitation, poor economy, harsh shifts (autos).
• Basic tools: multimeter, small screwdriver, scan tool if available.
• Service tip: check and clean earths, voltage instability can mimic a bad TPS.

FAQs

Does a 1998 Pajero diesel have a TPS?
Yes. The 4M40 turbo-diesel uses a throttle/accelerator position sensor. It feeds the ECU for EGR control, idle-up, and pump timing tweaks. While it doesn’t meter air like a petrol throttle, a faulty sensor still causes rough idle, stumbles, and noisy or smoky running.

How do you know the TPS needs replacing on a 1998 Pajero?
Look for a dead spot when you crack the throttle, surging at steady cruise, unstable idle, or harsh/late shifts on autos. A scan tool may show erratic throttle percentage. A multimeter sweep test that shows drop-outs confirms it.

Do you need to recalibrate the TPS after fitting?
On petrol models, set the base closed-throttle voltage to spec and clear codes. Many ECUs will relearn trims after a short drive. Some diesel variants benefit from an idle learn or pump control relearn via scan tool, but simple battery disconnects don’t always perform a full adaptation.