P0341 on 2003-2005 Mercedes E320 (W211): M112 Camshaft Sensor Guide

What's Unique About the 2003-2009 Mercedes-Benz E-Class

The Mercedes-Benz M112 V6 engine, unlike many V-type engines with two or four camshaft sensors, uses only one Camshaft Position Sensor (CPS). This simplifies diagnosis, as there's no need to determine which bank is at fault; P0341 directly points to this single sensor or its circuit. Failure of this sensor is a well-documented and very common issue on the M112 and related M113 V8 engines, often occurring after 100,000 miles. Failure of this sensor is a well-documented and very common issue on the M112 and related M113 V8 engines. Owners frequently report symptoms like a crank-no-start condition specifically when the engine is hot, which is immediately resolved by replacing this one part.

Generation note: The 2003-2009 E-Class covers the W211 generation. However, this guide is specific to the M112 3.2L V6 engine found in the E320 model from 2003 to 2005. Later E-Class models in this range used different engines (like the M272) which may have different sensor locations and designs.

Symptoms You May Notice

• Check Engine Light is on.
• Engine cranks but does not start, especially when the engine is hot (classic 'hot-soak' no-start).
• Difficulty starting, requiring extended cranking, which may progress to a complete no-start condition.
• Engine stalls unexpectedly, sometimes while driving or idling.
• Rough idle or engine misfires.
• Reduced engine power and poor acceleration.

Most Likely Causes

1. Failing Camshaft Position Sensor (CPS) 🔴 High Probability → Shop Engine Camshaft Position Sensor The camshaft position sensor is a known common failure item on M112 and M113 engines, often failing due to age and heat cycles in the engine bay. It is often recommended as a preventative replacement item around 100,000 miles.
   How to confirm: The most definitive test is replacing the sensor. Given the high failure rate and low cost, it's often the first and only step needed. A user on MBClub UK with a P0341 and hot-start issues confirmed a new Bosch sensor resolved the problem immediately.
   Typical fix: Replace the camshaft position sensor. It is held in by a single E8 external Torx bolt. 🎬 Watch: A quick walkthrough of the sensor replacement process. It's recommended to let the engine cool before replacement.
   Est. part cost: $40-$100
2. Damaged Wiring or Connector ⚪ Low Probability Engine bay heat can make the plastic connector and wiring insulation brittle over time, leading to cracks or a poor connection. Oil from leaking valve cover gaskets can also contaminate the connector.
   How to confirm: Visually inspect the wiring harness and the connector for the camshaft position sensor. Check for cracks, fraying, or signs of oil wicking up the harness. In one documented case, a new sensor did not fix the P0341, and the owner planned to test the continuity of the three sensor wires to the ECU. In another case, a mechanic found and repaired bad wires between the sensor and ECU, fixing the code and saving the owner from a $2,000 dealer-quoted harness replacement.
   Typical fix: Repair the damaged section of wire or replace the connector pigtail. In rare cases of widespread damage, a new engine wiring harness may be needed, but targeted wire repair is often sufficient.
   Est. part cost: $10-$400

Rare But Worth Checking

• Stretched Timing Chain: → Shop Engine Timing Chain While rare, a severely stretched timing chain can cause the camshaft and crankshaft signals to be out of sync, triggering a P0341 code. This would typically be accompanied by a rattling noise from the front of the engine, especially on cold starts.
• Faulty Engine Control Module (ECM): This is extremely rare. The ECM should only be considered a possibility after all other potential causes, including the sensor, wiring, and timing components, have been definitively ruled out.

Diagnosis Steps

1. Scan the vehicle's computer for trouble codes to confirm P0341 is present.
2. Allow the engine to cool down completely before working in the engine bay.
3. Locate the camshaft position sensor. On the M112 engine, it is on the front of the passenger-side (Bank 1) cylinder head, near the oil filler cap.
4. Inspect the sensor's electrical connector for damage, corrosion, or a loose fit. Press the tab to release and disconnect it. Check the wiring leading to it for any visible damage or brittleness.
5. Using an E8 External Torx socket, remove the single bolt securing the sensor.
6. Gently wiggle and pull the old sensor straight out. A small amount of oil may seep out, which is normal.
7. Ensure the old O-ring came out with the sensor. Lightly oil the O-ring on the new sensor and insert it into the cylinder head.
8. Re-install the E8 bolt and reconnect the electrical connector, ensuring it 'clicks' securely into place.
9. Clear the trouble code with a scan tool.
10. Start the engine. A successful repair is confirmed if the engine starts promptly (especially from hot) and the P0341 code does not return.

Parts You'll Likely Need

• Camshaft Position Sensor (OEM #0041531328 / A0041531328) — This is the most common cause of code P0341 on the M112 engine. It is a frequent wear-and-tear item that fails from heat and age. Part number is confirmed across multiple sources.
  Trusted brands: Bosch, Hella, Continental/VDO
  OEM price range: $80-$120
  Aftermarket price range: $40-$80

Platform-Specific Known Issues

• The M112 V6 only has one camshaft position sensor, located on the passenger side (Bank 1) cylinder head, making diagnosis for P0341 straightforward.
• It is highly recommended to use a quality OE-supplier part (like Bosch) for the replacement sensor. Forum users report that cheap, no-name aftermarket sensors can fail prematurely or be dead-on-arrival, forcing you to do the job twice.
• The most characteristic symptom of this failure on the M112 engine is the 'hot-soak no-start', where the car runs fine, is turned off, and then refuses to restart until it has cooled down for 20-30 minutes.

Mechanic-Grade Diagnostic Values

• Camshaft Position Sensor Power Supply Voltage — expected: 12 Volts (with key on, engine off). Failure: No voltage or significantly lower voltage indicates a wiring or ECU supply issue.
• Camshaft Position Sensor Signal Voltage (Hall Effect Sensor) — expected: A square wave switching between 0V and 12V when viewed on an oscilloscope while the engine is running or cranking.. Failure: A flat line, a noisy signal, or a signal that does not switch cleanly indicates a faulty sensor.
• Continuity Test from Sensor Connector to ECU — expected: Full continuity (less than 1 ohm of resistance) on all three wires between the sensor connector and the corresponding ECU pins.. 🎬 Watch: How to test sensor connector voltage and signals. Failure: High resistance or no continuity (OL) indicates a broken wire in the harness.

Wiring & Ground Locations

• Camshaft Sensor Connector (B6/1) — On the front of the passenger-side (Bank 1) cylinder head, near the oil filler cap.. This is the primary connection point to test. The connector itself can become brittle from heat, and the terminals can be contaminated by oil.
• ECU Connector Pins for Camshaft Sensor — At the Engine Control Module (ECM/ME-SFI control unit), typically located in the engine bay's control module box.. For advanced diagnosis, you must test continuity from the sensor to the ECU. The signal wire goes to pin 40, and the ground wire goes to pin 39 of the ECU connector.
• Engine Ground Strap — Typically a braided cable attached between the engine block/bell housing and the vehicle chassis.. A poor engine ground can cause a variety of erratic electrical issues and sensor faults. While not a direct cause of P0341, verifying the main engine ground is a good practice when chasing electrical gremlins.
• Connector Part Number — The 3-pin connector housing for the camshaft position sensor.. If the connector lock tab breaks during removal (a common issue), the housing can be replaced. The Mercedes part number for the 3-pole Hirschmann connector housing is A0225452426.

Real Owner Repair Stories

• MBWorld.org Forums (2004 E320, 134k miles) — Occasional no-start, P0341 code present.
  ❌ Tried (didn't work) Replacing the camshaft position sensor with a new one did not fix the problem.
  ✅ What actually fixed it The owner planned to perform a continuity check on the three sensor wires (ground, 12V, signal) to the ECU, suspecting a wiring issue. This highlights that when a new sensor doesn't work, the wiring harness is the next logical suspect.

OEM Part Supersession History

• 0041531328 / A0041531328 → This part number appears to be stable with no common supersessions noted in parts catalogs. — N/A
  Heads up: While the part number is stable, there is a significant difference in sensor design between the M112 V6 and M113 V8 engines, even though they are related. A sensor for an M113 (e.g., from an E500) will not fit or work in an M112, despite both being from the W211 platform.

Diagnostic Flowchart

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0335 — Crankshaft Position Sensor A Circuit - Often confused with P0341. The context notes that camshaft position sensor symptoms (like the hot-soak no-start) can be very similar to a failing crankshaft position sensor, which is another common M112 failure point.
• P0300 — Random/Multiple Cylinder Misfire Detected - A failing camshaft position sensor on the M112 can cause rough idling and engine misfires, triggering this code alongside P0341.
• P0340 — Camshaft Position Sensor 'A' Circuit - A closely related generic OBD-II code for the camshaft position sensor circuit, which can trigger under the same conditions (failing sensor or brittle wiring harness) as P0341.
• P0301 — Cylinder 1 Misfire Detected - Related to the engine misfires symptom caused by the ECU losing camshaft sync due to a failing sensor or oil-contaminated connector.

Frequently Asked Questions