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2015 Honda Pilot P3400 Code: No Start Issue and Cylinder Deactivation System Diagnosis

Model: Honda Pilot Fault Code: P3400 Posted: 2020-03-07 14:48

Hello, I own a 2015 Honda Pilot that has been experiencing intermittent knocking, which recently escalated to a complete failure to start. The check engine light triggered with code P340-0 (Bank 1 Cylinder Pressure Sensor), indicating an issue with the cylinder deactivation system. When I attempt to start the vehicle, it sounds like either the timing belt has broken or there is no compression. However, my compression test results show normal readings. I replaced the Bank 1 Cylinder Pressure Sensor (P3400) according to the diagnosis, but the issue persists and the car still won’t start. I’m seeking further guidance on how to diagnose and resolve this 'no-start' condition when P3400 is present. Most online resources mention a rough idle or performance issue with the sensor failure, but they don't address why the engine fails to start entirely. I’ve tested the sensor wiring and found no ground path—yet the vehicle still won’t crank properly. Any insights into potential underlying causes or diagnostic steps for this specific P3400-related no-start scenario would be greatly appreciated. Thank you in advance.

Related fault codes
P3400
Comments (2)
Anonymous 2020-03-07 15:27

If you haven't already, start with the official Honda Technical Service Bulletin (TSB) for P3400 on the 2015 Pilot. Several TSBs address this code and may indicate a need to reflash the Powertrain Control Module (PCM). Check out this resource for relevant PDFs: https://www.carcomplaints.com/Honda/Pilot/2015/tsbs/ This bulletin might explain whether the sensor issue is software-related or if hardware components require further inspection.

Anonymous 2020-03-07 18:13

Thanks for the link—I’ve reviewed it and found it very informative. However, it doesn’t specifically address my 'no-start' problem. All the information points to a running engine with rough performance when the sensor fails, but I’m struggling to understand how to diagnose or fix a complete failure to start. I tested the cylinder pressure sensor and confirmed there’s no ground connection—yet the vehicle still won’t start at all. This suggests either a deeper electrical issue, a faulty PCM signal, or a problem with the engine control system beyond just the sensor itself. I’m looking for guidance on how to troubleshoot this specific failure mode when P3400 is present and the engine doesn't respond at all.