Parts for your 1993 Toyota Hilux surf-Knock sensor

1993 Toyota Hilux Surf knock sensor — which models have one, and how to look after it

Referencing Toyota’s technical materials for the 130‑series Hilux Surf (factory Repair Manuals, the 1993 Wiring Diagrams, and the Toyota Electronic Parts Catalogue), the presence of a knock sensor depends on the engine. The petrol models — RN130 with the 22R‑E and VZN130 with the 3VZ‑E V6 — are fitted with a knock sensor and show a KS signal to the ECU in the EWD, along with a diagnostic path for code 52 (knock sensor circuit). The diesel models — LN130 with the 2L‑TE and early KZN130 with the 1KZ‑TE — do not list a knock sensor in the EPC or the wiring diagram, and their engine control sections do not carry a knock‑sensor diagnostic.

Why no knock sensor on the diesels? On these early‑90s Toyota diesels, combustion is controlled by injection timing and fuel delivery rather than spark, and “knock” isn’t managed the same way as on petrol engines. The diesel ECUs of the era use sensors like the timing/needle‑lift, boost, coolant temp, and air temp — there’s no detonation control via a knock sensor in the factory documentation for 2L‑TE or early 1KZ‑TE Hilux Surf applications.

For petrol Surfs that do have a knock sensor, the part is there to keep the engine happy on Aussie and Kiwi roads, even with variable fuel quality. The sensor is a little piezo “microphone” that listens for detonation (that sharp ping under load). When it hears knock, it tells the ECU to trim ignition timing just enough to protect the pistons and head while keeping power and economy on point. On the 3VZ‑E V6 (VZN130), the sensor sits in the valley under the intake, and on the 22R‑E (RN130) it’s threaded into the block on the intake side of the engine. There’s no routine replacement interval — they’re a fit‑and‑forget item — but a crook sensor or brittle sub‑loom will trigger a Check Engine Light with code 52 and can make the Surf feel flat as the ECU pulls timing to stay safe.

• Typical symptoms: CEL with code 52 (on OBD1), sluggish performance, poor fuel use, or persistent pinging under load.
• Service tips: Inspect the shielded knock‑sensor wire for cracking or oil soak, especially on the V6 under the manifold. Ensure the mating surface on the block is clean and dry.
• Replacement advice: Use an OE or quality aftermarket sensor, avoid sealants or Teflon on the threads (it needs a clean metal‑to‑metal contact). Tighten to the factory spec with a torque wrench and route the harness away from heat.
• Good opportunities to replace: Any time the intake manifold (3VZ‑E) is off, during head work, or when chasing a persistent code 52 after confirming the loom is sound.
• After fitting: Clear codes, take it for a gentle drive, and check for returning faults. If pinging continues, verify fuel quality and base ignition timing per the workshop manual.

Owners who are unsure which engine they’ve got can check the build plate (RN/VZN = petrol with knock sensor, LN/KZN = diesel without one in 1993 Surf spec) or glance at the intake layout — the V6’s sensor hides under the upper plenum, while the 22R‑E’s sits mid‑block.

Does a 1993 Hilux Surf diesel have a knock sensor?

No. The 2L‑TE and early 1KZ‑TE Hilux Surf models don’t use a knock sensor in factory form. Their control strategy relies on injection timing, boost, and temperature inputs rather than detonation feedback.

Where’s the knock sensor on a petrol 1993 Hilux Surf?

On the 3VZ‑E V6 it’s bolted into the valley beneath the intake manifold, the upper plenum usually needs to come off to reach it. On the 22R‑E four‑cylinder it’s threaded into the block on the intake side, roughly mid‑way along.

What are the signs the knock sensor or its wiring is playing up?

Expect a Check Engine Light with code 52 on OBD1, lacklustre acceleration, and worse fuel use as the ECU runs conservative timing. Sometimes the sensor is fine and the shielded sub‑loom is the real culprit, so always check the wiring before throwing parts at it.