Parts for your 2004 Toyota Prius-Crank angle sensor

2004 Toyota Prius crank angle sensor: purpose, servicing and replacement tips

Technical sources confirm the 2004 Toyota Prius (NHW20, 1NZ‑FXE engine) does use a crank angle sensor, also called a crankshaft position sensor (CKP). It’s monitored by the engine control module to synchronise ignition and injection timing and to coordinate engine starts via MG1 in the Hybrid Synergy Drive.

• Toyota Repair Manual for 2004 Prius (RM1075U): Engine/Hybrid System diagnostics include DTC P0335/P0339 for the crankshaft position sensor (NE signal) and related inspection steps.
• Toyota Electrical Wiring Diagram for 2004 Prius (EWD, model NHW20): shows the CKP (NE) signal routed to the ECM.
• Toyota Electronic Parts Catalogue (EPC) for NHW20: lists a “Sensor, Crank Position” for the 1NZ‑FXE engine.

On this Prius, the CKP quietly keeps the petrol engine running sweet. The hybrid system spins the engine up with MG1, but the ECM still needs precise crank angle data to know exactly where each piston is. If the CKP goes out to lunch, expect rough running, stalling, a no‑start or the engine dropping out while the car soldiers on in EV—sometimes masking the fault. The dash will usually light the MIL and store P0335 or P0339.

It’s not a scheduled service item, so there’s no routine replacement. As part of good servicing, a tech will check for oil leaks around the timing cover that can soak the sensor or connector, make sure the harness isn’t chafed, and confirm clean, tight terminals. If the car logs CKP‑related codes or shows the classic symptoms, replacement is the go. Use an OE‑quality sensor and a fresh O‑ring, lightly lubricated before fitting. The sensor lives at the front of the engine (bonnet side), mounted to the lower timing cover near the crank pulley, held by a small bolt. Always disconnect the 12‑V battery before unplugging engine sensors and steer well clear of orange high‑voltage cabling.

No special programming is required, once fitted, clear codes and perform a road test. Because hybrids can mask engine hiccups, it’s worth scanning for pending faults if you notice odd transitions between EV and engine drive or a sudden nudge in fuel economy over a few hundred kilometres.

For DIYers, axle stands and the undertray off make access easier. If in doubt, leave it to a qualified sparky or mechanic—especially given the hybrid gear under the bonnet.

Popular questions

Does a 2004 Prius have a crank angle sensor?
Yes. Toyota’s 2004 Prius (NHW20) uses a crankshaft position (crank angle) sensor. It’s covered in Toyota’s Repair Manual under DTC P0335/P0339 and shown in the Electrical Wiring Diagram as the NE signal to the ECM.

Where is the crank angle sensor on a 2004 Prius, and what are the failure symptoms?
It’s mounted to the lower timing chain cover near the crank pulley at the front of the engine. Common symptoms include a check engine light, codes P0335/P0339, hard starting or no‑start, intermittent stalling, and rough running. The hybrid system can sometimes glide through a stall, making the issue less obvious.

Is replacing the CKP on a Gen 2 Prius a DIY job?
Often, yes, for a competent home mechanic. Access is from the front underside with the splash shield removed. Disconnect the 12‑V battery, swap the sensor and O‑ring, and refit the bolt to the workshop‑specified torque. Avoid any contact with orange high‑voltage wiring. If scanning and confirming the fault isn’t your thing, a workshop visit is the safer bet.