P1794 on 2014-2018 Mazda Mazda3 (s Grand Touring, s Touring with i-ELOOP) — Capacitor (i-ELOOP) System Malfunction
1 vehicles · 1 makes · $600-$1,800 repair
Most Reported On
P1794 is an OBD-II diagnostic trouble code meaning “Capacitor (i-ELOOP) System Malfunction.” The PCM monitors the i-ELOOP electric double-layer capacitor and the DC-DC converter that steps its stored voltage down to the 12-volt system. P1794 sets when the capacitor circuit does not charge, discharge, or report correctly - most commonly an open or high-resistance path in the signal harness between the DC-DC converter and the capacitor. Mazda documented that an oxide film can form on the terminals of that signal-harness connector, which is a key root cause of this code. This code is most commonly reported on 2014-2018 Mazda Mazda3 (s Grand Touring, s Touring with i-ELOOP), with repair costs ranging from $600 to $1,800.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
P1794 does not use the standard P/B/C/U prefix. It may be a manufacturer-specific code, so verify that a scanner supports your exact year, model and module before buying.
FAQ
What does P1794 mean?
P1794 stands for "Capacitor (i-ELOOP) System Malfunction." The PCM monitors the i-ELOOP electric double-layer capacitor and the DC-DC converter that steps its stored voltage down to the 12-volt system. P1794 sets when the capacitor circuit does not charge, discharge, or report correctly - most commonly an open or high-resistance path in the signal harness between the DC-DC converter and the capacitor. Mazda documented that an oxide film can form on the terminals of that signal-harness connector, which is a key root cause of this code.
What are the most common causes of P1794?
The most common causes of P1794 are: Oxide film on the signal-harness connector terminals between the DC-DC converter and the capacitor (Mazda-documented cause), Failed i-ELOOP capacitor assembly with an internal open circuit, Failed DC-DC converter, Open or damaged wiring between the capacitor, DC-DC converter, and alternator, Poor ground or corroded connector terminals. The specific cause varies by vehicle.
How much does it cost to fix P1794?
Repair costs for P1794 range from $600 to $1,800, depending on the vehicle and root cause.
Which vehicles are affected by P1794?
Au7o has documented P1794 across 1 vehicle models from 1 manufacturers: Mazda.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.