Parts for your 2001 Holden Commodore-Knock sensor

2001 Holden Commodore Knock Sensor: Yes, It’s Fitted and It Matters

Based on the Holden VX Commodore Service Manual (Engine Controls), GMH Service Information for VX/VY, GM Powertrain LS1 engine documentation, and Bosch knock-sensing technical papers, the 2001 Holden Commodore is equipped with a knock sensor system. All 2001 VX variants use it: the 3.8L Ecotec V6 (including supercharged L67) runs a block-mounted knock sensor, while the 5.7L Gen III LS1 V8 uses two knock sensors mounted in the valley beneath the intake manifold. Those sensors let the ECU listen for detonation and trim ignition timing to protect the engine and keep it running sweet on Aussie and Kiwi fuels.

What’s the point of the knock sensor? It hears high-frequency vibrations caused by knock (pinging) and signals the ECU to back off timing just enough to stop the knock without killing performance or economy. It’s a quiet hero for reliability—especially on hot days, under load, or when fuel quality varies. That’s why Holden’s own service literature (VX Engine Controls) and GM’s LS1 documentation treat knock sensing as core to engine management, not an optional extra.

If the knock sensor or its wiring plays up, the car can feel flat, the check engine light may glow (codes like P0325–P0333), fuel use can climb, and in the worst case the engine can suffer detonation damage. It’s not a routine replacement item, but it deserves attention during scheduled servicing—particularly on higher-kilometre cars.

• Inspection tips: check the harness and connector condition, look for oil or coolant contamination, and confirm the sensor is torqued correctly to spec (use a torque wrench, not “that’ll do”).
• LS1 specifics: the two sensors sit under the intake, water can pool in the valley if the intake grommets or valley cover seal are tired. When replacing, clean the valley, renew grommets/seals, and route the sub-loom properly to avoid moisture. Genuine or OEM-quality sensors are strongly recommended.
• V6 specifics: the sensor threads into the block, ensure the mating surface is clean, don’t use thread tape, and torque to spec so it can “hear” properly.

Replacement is straightforward if the right steps are followed. On the V6 it’s typically an external job with clear access. On the LS1, the intake has to come off, so many owners bundle it with intake gasket renewal and a fresh knock sensor harness. After fitment, clear codes and road test under load to confirm the ECU is happily trimming timing without recurring faults.

Popular questions about the 2001 Holden Commodore knock sensor

Where is the knock sensor on a 2001 Commodore?
On the 3.8L V6, it’s mounted into the engine block. On the 5.7L LS1 V8, there are two sensors tucked under the intake manifold in the valley. Access on the V6 is generally easier, the LS1 usually needs the intake removed to reach them properly.

Can it be driven with a faulty knock sensor?
It’ll usually start and run, but the ECU often pulls timing as a safeguard. That can make it feel gutless and chew more fuel. More importantly, without reliable knock feedback there’s a risk of detonation under load. Best practice is to fix it promptly rather than drive on and hope.

What does a replacement typically involve?
V6 jobs are commonly a sensor swap with a torque check and a quick harness inspection. LS1 jobs involve removing the intake, cleaning the valley, renewing grommets/seals, and often replacing the sub-loom to prevent future moisture issues. Always clear codes and verify with a proper road test.