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P0340 Camshaft Position Sensor Fault - 2004 Ford Focus 2.0L Zetec Engine Diagnosis and Solutions

Model: 2004 Ford Focus Fault Code: P0340 Posted: 2018-10-21 18:40

Hi everyone, I'm new here and recently experienced a return of the P0340 camshaft position sensor fault on my 2004 Ford Focus with a 2.0L Zetec engine. This issue first appeared several years ago — I took it to the dealership at that time, where they diagnosed the code as related to the camshaft position (CMP) sensor but confirmed the physical sensor was fine. They suspected interference from the Mass Airflow (MAF) sensor and cleared the code. After four years, the P0340 code returned. I've since tried measuring transmission solenoid resistance, which raised concerns about possible electrical shorts. Clearing the code initially helped — the check engine light would stay off for up to 300 miles — but over time, the intervals between occurrences got shorter. The vehicle now runs roughly with reduced power. I'm wondering if this could be due to: - A failing camshaft position sensor or wiring - Corroded or dirty electrical connections - Oil contamination from the valve cover seeping into the sensor - Low battery voltage affecting sensor readings (I cleaned corrosion and applied protective coating; battery fluid level appears normal) - Parasitic electrical draw causing intermittent power fluctuations I don't have any other active OBD2 codes currently, though I previously had a weak battery code that cleared after maintenance. The original dealer report from 2014 noted a baro reading of 137Hz (should be 158Hz), and the O2 sensor was functioning correctly at the time. They also performed a wiggle test on the harness, which didn't induce a fault. I don’t have access to live data or freeze frame files through my current OBD reader. Any insights into troubleshooting this P0340 issue specifically for 2004 Ford Focus models with 2.0L Zetec engines would be greatly appreciated.

Related fault codes

P0340

Comments (2)

Anonymous 2018-10-25 12:09

Could you confirm the exact engine type (2.0L or 2.3L) and the 8th character of your VIN (e.g., 3, 5, P, Z)? Also, are there any other diagnostic codes present? What is the configuration of the camshaft position sensor — 2-wire or 3-wire? Are freeze frame data logs available in your OBD2 system? If so, what does the engine speed and sensor reading look like during fault conditions?

Anonymous 2018-10-25 13:14

Thanks for the detailed response! My vehicle is equipped with a 2.0L Zetec engine, and the 8th character of my VIN is '3'. There are currently no other active OBD codes, though I once had a weak battery code that cleared after cleaning terminals and checking fluid levels — I believe low voltage might have interfered with sensor operation. I cleaned all connections and applied protective coating. The battery appears to be in good condition with proper electrolyte level. I’ve heard rumors of parasitic draws causing intermittent faults, so I’m wondering if there’s a hidden electrical drain in the system. Regarding the camshaft sensor wiring — I don’t know whether it's 2 or 3 wires. You're referring to the freeze frame file, which I understand is part of the OBD2 diagnostic data that shows real-time readings during fault events. Unfortunately, my current device doesn't support live data viewing. Here’s the original dealer report from 2014: "Customer reports check engine light on. RPMs appear higher than normal. Vehicle ran rough at one point. Codes P0340 (CMP) and P2195 (HO2S11 stuck lean) were found — neither is a hard fault and were cleared. Engine baro reading was 137Hz (should be 158Hz). O2 sensor readings were normal. CMP sensor PID showed no fault during monitoring. Wire harness wiggle test failed to induce error. Codes cleared, KAM reset. Road test showed no issues at that time." Any advice on how to diagnose or resolve this P0340 issue in a 2004 Ford Focus would be very helpful! Thanks again.