P0366 on Buick: How to Diagnose & Fix
Camshaft Position Sensor "B" Circuit Range/Performance (Bank 1)
1 Buick model · 1 documented issue
P0366 on Buick by model: symptoms, diagnosis and fix
2017-2018 Cascadas with the 1.6L LWC can set a check engine light with P0366 (exhaust camshaft position sensor circuit range/performance) and/or P0014 (exhaust cam timing over-advanced) with no driveability complaint. GM's bulletin 17-NA-338 (October 2017) says the cause is an exhaust cam phaser that sporadically fails to lock and oscillates during engine start, which the ECM misreads as a timing fault. The codes are false; there is no mechanical phaser or timing chain defect, so replacing the phaser, actuator solenoid or cam sensor does not fix it.
Common Symptoms
- Check engine light shortly after a cold start
- P0366 stored
- P0014 stored
- No noticeable running problem
How to Fix
Reprogram the engine control module with the latest calibration via SPS (GM 17-NA-338, listed in the Cascada TSB record as 'ECM update to correct MIL illumination'). Do not replace hardware first. Under the 8yr/80k emissions or bumper-to-bumper warranty the reflash is free; out of warranty a dealer reflash is typically $120-$200. If the codes return after the update, then diagnose the phaser, cam sensor and oil control valve per SI.
Sources for this issue (2)
P0366 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0366 mean on a Buick?
P0366 stands for "Camshaft Position Sensor "B" Circuit Range/Performance (Bank 1)." This code indicates the 'B' camshaft position sensor on Bank 1 is electrically present but its signal is out of the expected range or inconsistent with the crankshaft position signal. The PCM uses this sensor to track camshaft timing for fuel, spark, and variable valve timing control. A range/performance fault can cause rough idle, hesitation, reduced power, or hard starting. It often points to sensor or timing alignment issues rather than a fully open circuit. On Buick it is documented across 1 model: Cascada.
What are the most common causes of P0366?
The most common causes of P0366 are: Failing camshaft position sensor (Bank 1, sensor B), Damaged reluctor/tone ring or excessive air gap, Timing chain/belt stretch or jumped timing, Wiring/connector intermittent fault or corrosion, Oil contamination on the sensor, Variable valve timing actuator fault. The specific cause varies by vehicle.
How much does it cost to fix P0366 on a Buick?
Repair costs vary widely with the root cause and Buick model; each issue on this page carries its own estimate where one is published.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.