Fix P0366: Mechanic’s solutions that WORKED

The P0366: Camshaft Position Sensor “B” Circuit Range/Performance (Bank 1) code indicates a potential issue with the Camshaft Position Sensor “B” in Bank 1 of the engine. This sensor plays a critical role in monitoring the position of the camshaft and ensuring it is timed correctly with the crankshaft. Problems with this sensor can affect the engine’s timing, leading to a range of performance issues.

P0366 quick overview

Meaning	P0366: Camshaft Position Sensor “B” Circuit Range/Performance (Bank 1)
Is it serious?	This code can be serious as it relates to the engine’s timing, which, if incorrect, can lead to poor vehicle performance or engine damage.
Possible causes	– Incorrect camshaft timing – Faulty camshaft position sensor – Damaged or corroded wiring or connectors – Mechanical timing issues like a stretched timing chain – Issues with the camshaft chain tensioner – Problems due to recent engine rebuild or repairs
How to diagnose?	Verify Camshaft Timing: Check if the camshaft timing is correct and aligned properly. Inspect Sensor and Wiring: Examine the camshaft position sensor and associated wiring for damage or disconnections. Conduct Compression Test: Perform a compression test to identify any mechanical issues that might indicate timing problems. Review Engine Rebuild Work: If the engine was recently rebuilt, assess the work done for potential issues. Use Labscope for Analysis: Analyze the sensor signal with a labscope for any irregularities. Compare Waveforms: If available, compare the sensor’s waveform with known good patterns.

How to fix P0366 – learn from mechanics

I looked into P0366 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Audi

Vehicle Information: 2005 Audi A6 Quattro 3.2L

Issue + Repair History:

• MIL (Malfunction Indicator Lamp) on.
• Codes P0341 and P0366 related to camshaft sensors.
• VVT solenoids checked for debris; found to be okay.
• Codes persisted after clearing and restarting the engine.
• Swapping all 4 sensors did not change the code location.
• Wiring to the ECM appeared normal.
• Timing chain tensioner on bank B found to be broken, leading to the decision to send the vehicle to the dealer for repair.

Suggestions to Fix Issue:

• Scope the Camshaft Position Sensors (CMPs) and compare to the Crankshaft Position Sensor (CKP).
• Check if the engine’s timing is causing the codes.
• Use an Audi-capable scanner to view measuring blocks and monitor camshaft adjustment.
• Inspect the timing chain tensioner for looseness.
• Check oil pressure to ensure proper timing chain tension.
• Look for poor connections at the sensor.
• Consider the possibility of stretched belts and issues with VVT not actuating.

Final Fix: The issue was resolved by addressing the broken timing chain tensioner on bank B. The vehicle was sent to the dealer for repairs due to the need for special tools.

Case #2: Mercedes

Vehicle Information: 2005 Mercedes-Benz C230 Kompressor 1.8L

Issue + Repair History:

• Poor idle quality, misfires, poor fuel economy, MIL lamp on.
• Popping sound around the supercharger.
• Found and repaired a vacuum leak.
• Replaced spark plugs, coils, right exhaust cam sensor, and air mass meter.
• Despite repairs, cam sensor code (P0366) still present and vehicle occasionally runs poorly with bad fuel mileage.
• Misfire codes present on all 4 cylinders.

Suggestions to Fix Issue:

• Check if the engine timing is off, possibly due to chain stretch.
• Investigate the timing chain, as it may have moved out of alignment.
• Examine fuel trims and O2 sensor readings.
• Test the cam sensor directly.
• Check for stretched timing chain.
• Inspect cylinder heads and the possibility of binding exhaust valves.
• Consider issues with difficult adaptation reset.

Final Fix: The problem was resolved by addressing a vacuum leak.

Case #3: Chevrolet

Vehicle Information: 2009 Chevrolet Traverse LT 3.6L

Issue + Repair History:

• MIL lamp on, code P0366 for right exhaust cam sensor.
• Engine recently rebuilt, but details of the rebuild unclear.
• Basic circuit tests conducted, including checking 5v reference and ground at connector.
• Signal from sensor scoped and appeared clean.
• Unable to activate cam actuators due to the code.
• Possibility of bad or incorrect exhaust cam phaser.
• No correlation codes, suggesting timing might be correct.
• Engine runs fine, and customer has been driving it.

Suggestions to Fix Issue:

• Compare cam/crank sensor waveform with a known good pattern.
• Check for issues with cam/crank timing, possibly due to chain stretch or incorrect cams.
• Inspect the cam reluctor for bending or damage.
• Examine camshaft end play and adjust if necessary.
• Consider potential issues with cam reluctor or sensor mounting.
• Check for variance in engine timing, bank to bank.
• Inspect cam reluctors for cracks or breakage.

Final Fix: The issue was referred back to the team that performed the engine rebuild. The exhaust cam on bank 1 was found to pattern before bank 2 significantly. The possibility of an advanced exhaust cam on bank one was suggested, which might require moving the chain. The exact final fix was not explicitly detailed.

Case #4: Honda

Vehicle Information: 2004 Honda Odyssey LX 3.5L

Issue + Repair History:

• MIL lamp on, P0366 code indicating camshaft position sensor “B” circuit range/performance (Bank 1).
• Timing belt and water pump replaced 3 weeks prior.
• After initial reset, code reappeared; vehicle exhibited reduced acceleration.
• Recent oil change with 5w20 synthetic oil.
• Vehicle operates well in terms of acceleration.

Suggestions to Fix Issue:

• Check if the Bank 1 cam is aligned correctly.
• Inspect sensor signal with a labscope for a clean signal.
• Test cam position sensor resistance and wiring.
• Recheck timing belt installation for correct alignment.
• Consider possibility of being off by one tooth on the Bank 1 camshaft.
• Inspect for any coolant spillage on wiring or connectors.
• Check crankshaft position sensor and other sensors sharing the 5v reference.

Final Fix: The issue was resolved by addressing a timing issue. The front cam was off by one tooth, which significantly impacted the vehicle’s performance, especially in colder temperatures. Correcting the cam alignment resolved the problem.

Case #5: Audi

Vehicle Information: 2005 Audi A6 Quattro 3.2L

Issue + Repair History:

• Initially, the car had a no-start condition, but later it started and stalled with open throttle.
• Check Engine Light flashing with EPC failure indicated in the cluster.
• Codes: P0341, P0366, P0346, P0391 (all CMP sensor codes), P0301, P0302, P0303 (misfire), P2247 (B2S1 reference voltage).
• Spark and injector pulse checked – both good.
• One cam actuator solenoid broke during inspection, replaced.
• Compression test results varied significantly across cylinders.
• Bank 1 spark plugs were dripping with fuel.
• Replaced all spark plugs and coils.
• Checked for blocked catalytic converter – found to be clear.
• Removed Bank 1 timing cover to inspect chain guides; none broken.
• Vehicle could run at high RPM but would not idle; Bank 1 produced no exhaust heat.

Suggestions to Fix Issue:

• Check for timing issues using a scope to sync cylinder compression with ignition coil 1 for cam-crank correlation.
• Investigate fuel pressure.
• Re-examine all timing marks for potential timing issues.

Final Fix: The problem was resolved by replacing the left cam timing chain tensioner and guide assembly. Despite initial focus on the right side of the engine due to misfire codes and cold exhaust, the issue was with the left cam timing chain tensioner. Special tools were required for the repair.

Advice	Brief Description of Diagnostic Step
Check Camshaft Timing	Verify the alignment of the camshaft timing marks, ensuring they are in sync.
Inspect Camshaft Position Sensor	Examine the sensor for any damage or connectivity issues.
Review Compression Test Results	Conduct a compression test to identify discrepancies that might indicate timing or mechanical issues.
Examine Camshaft Chain Tensioner	Check the camshaft chain tensioner for wear or failure, as it can impact timing.
Use a Labscope for Signal Analysis	Analyze the camshaft sensor signal with a labscope for irregularities.
Consider Engine Rebuild History	If the engine was recently rebuilt, review the work for potential timing errors.
Compare with Known Good Waveforms	Use reference waveforms to compare and identify deviations in sensor signals.