Guide workflow for drivers
Use the guide, not a guess.
Clear answers for DIY drivers about CrankKey’s free browser-based code lookup, its no-adapter boundary, and the read-only meaning of scan-result references.
Quick definitions
Diagnostic terminology
These plain-English definitions explain labels used in CrankKey’s scan reports.
CrankKey provides general diagnostic information; it does not confirm a diagnosis for a specific vehicle.
- Pending DTC
- A code stored when the OBD system detects a potential malfunction. The system may use later drive cycles to evaluate it before confirming a malfunction.EPA OBD DTC definitions (40 CFR § 86.010-2)
- Permanent DTC
- A DTC that corresponds to a MIL-on DTC and is stored in non-volatile memory. Only the vehicle’s OBD system can erase it; a scan tool or other human interaction cannot.EPA OBD DTC definitions (40 CFR § 86.010-2)
CrankKey’s connected scan is read-only and does not clear codes. A permanent DTC is erased only by the vehicle’s OBD system after its requirements are met; clearing codes is not a repair, and faults may return.
- Freeze Frame Data
- A recorded snapshot of vehicle operating conditions associated with a fault or DTC. It may be unavailable on some vehicles or in some scans. The cited federal OBD rule applies to heavy-duty engines used in applications over 14,000 lb GVWR.EPA heavy-duty OBD requirements for engines used in applications over 14,000 lb GVWR (40 CFR § 86.010-18)
- Module
- A vehicle computer, also called an electronic control unit (ECU) or electronic control module, that controls one or more electrical systems. A scan response confirms that a computer answered, but not which module answered.EPA-approved California Title 13, Division 3, Chapters 3.5–3.7 compilation (ECU definition)
- Diagnostic Trouble Code (DTC)
- A code reported by a vehicle diagnostic system to identify a detected fault condition. CrankKey’s connected DTC decoding is experimental pending independent validation; results may be unknown or partial. Model-specific coverage limitations are not yet characterized because no dated, diverse-vehicle CrankKey test evidence is documented in this checkout. SAE J2012 and ISO 15031-6 describe standardized DTC scope; neither independently validates CrankKey’s decoder or its vehicle coverage.
- Fuel trim
- A value describing an engine controller’s adjustment to fuel delivery. Its meaning depends on the vehicle and the scan context.
- Coolant temperature
- A reported temperature value for the engine coolant. Check the vehicle service manual for model-specific interpretation.
- SAE J2012
- SAE J2012 describes standardized diagnostic trouble-code definitions. Its scope does not validate CrankKey’s decoder or vehicle coverage.Official SAE J2012_202509 page
- ISO 15031-6:2015
- ISO 15031-6:2015 describes standardized DTC formats and definitions for emissions-related diagnostics. Its scope does not validate CrankKey’s decoder or vehicle coverage.Official ISO 15031-6:2015 page
- CARB OBD II regulations
- The CARB OBD II regulations index points to applicable current California regulations; applicability depends on the vehicle and jurisdiction. CrankKey does not claim EPA or CARB compliance.Official CARB OBD II regulations index