C121C — OBD-II trouble code

A chassis OBD-II trouble code. Below are the vehicles and failure patterns where owners report it, drawn from NHTSA complaints.

In ProblemsByVin's analysis of the NHTSA owner-complaint record, owners cite C121C across 6 vehicle failure patterns. Diagnostic codes in complaints are reported by owners and are unverified — they point to where this code shows up, not a confirmed diagnosis. Open a page below for the full pattern (symptoms, mileage, repair costs owners cite).

Vehicles where owners report C121C 6 patterns

2016 Jeep Wrangler

powertrain — Engine stalling under normal operation

2013 Jeep Wrangler

powertrain — Loss of power and limp mode during highway driving

2009 Volkswagen Routan

steering — Engine Shutdown with Power Loss (Ignition/Electrical)

2008 Jeep Liberty

powertrain — Check Engine/Traction Control Light with Sensor Code C121C

2007 Chrysler Pacifica

engine — Unexplained stalling without warning

2007 Jeep Grand Cherokee

engine — Engine stalling—random, without warning

Codes are pulled from what owners wrote in their NHTSA filings — they're allegations, not a shop diagnosis. Always confirm with a live scan. Browse all diagnostic codes →