Parts for your 2009 Honda Civic-Camshaft sensor

2009 Honda Civic camshaft sensor — what it does and how to look after it

Yes, the 2009 Honda Civic is fitted with a camshaft position sensor (CMP). This is confirmed by OEM service literature and parts catalogues: Honda Civic 2006–2011 Service Manual (PGM-FI section, CMP Sensor Circuit, DTC P0340/P0341), Honda Electronic Parts Catalogue listings for 2009 Civic R18A engines (CMP sensor assembly part family 37510-RNA-xxx) and K20-powered Si/Type R variants (intake/exhaust CMP sensors), plus independent service databases that document test procedures and specifications. These technical sources make it clear the CMP sensor is an essential input for the Civic’s PGM-FI and i-VTEC systems.

On a 2009 Civic, the camshaft sensor tells the engine control module exactly where the camshaft is in relation to the crank. That lets the ECU run true sequential fuel injection, control spark timing, and phase i-VTEC correctly for smooth idle, strong mid-range, and good economy. Without a clean CMP signal, the car can crank longer, run rough, misfire, drop into limp mode, or throw the check engine light with codes like P0340/P0341.

There’s no fixed maintenance interval for the CMP sensor — it’s a solid-state component — but it benefits from simple checks during regular servicing. Under the bonnet, make sure the connector is tight and clean, wiring isn’t chafed, and there’s no oil seeping past the sensor’s O-ring. On R18 models you’ll find a single sensor at the cylinder head, K-series performance variants may have two (intake and exhaust).

Replacement is straightforward with basic tools. Disconnect the battery, unplug the connector, remove the retaining bolt, and gently twist the sensor out. Lightly oil the new O-ring, seat the sensor squarely, and torque the bolt to spec (around 9–12 N·m, always follow trusted service data). Clear any stored fault codes and road test. If oil was present in the connector, inspect and clean the plug, and consider replacing the pigtail if the seal is compromised.

Use a quality OEM or reputable aftermarket sensor, cheap copies can cause intermittent faults that are maddening to trace. If the Civic is doing lots of short trips or high-kilometre duty, adding a quick electrical and leak check of the CMP sensor at each service helps catch issues early, keeping starts crisp and i-VTEC behaviour spot-on.

• Common signs of trouble: hard starting, rough idle, poor fuel use, reduced power, and the MIL on with P0340/P0341.
• Tip: Always handle the sensor and O-ring with clean hands — grit can cause sealing issues and false triggers.

Popular questions

Where is the camshaft sensor on a 2009 Honda Civic?
On most 1.8-litre R18 models it’s mounted on the cylinder head near the end of the camshaft, accessible from the top/front of the engine under the plastic cover. Performance K-series variants may have two sensors, one on each cam. A quick look at the valve cover area will usually spot the small, two- or three-pin sensor held by a single bolt.

Can a 2009 Civic drive with a bad camshaft sensor?
Sometimes it will, but it’s not ideal. The ECU may fall back to less precise strategies, causing hard starts, poor performance, and higher fuel use. Prolonged driving risks stalling or catalyst damage from misfires. Best to diagnose and sort it promptly if the light’s on with CMP-related codes.

Does the 2009 Civic have one or two camshaft sensors?
The common 1.8-litre R18 uses one CMP sensor. K-series performance models (like the Si/Type R) typically use two — one for the intake cam and one for the exhaust cam — to support more advanced cam phasing control.