CrankKey diagnostic help
Freeze-Frame Data: Plain-English Field Guide for CrankKey Diagnostic Help
Freeze-frame data is a snapshot of vehicle operating conditions recorded when a fault is detected. A saved record can include a diagnostic trouble code and the parameter values returned for that snapshot.
Before you begin
Preserve the evidence before you repair
Before disconnecting the battery, clearing codes, or starting a repair, save what the vehicle and scanner are showing. A quick record can keep useful context from being erased.
Step 1
Record every code and its status
Write down or photograph every displayed diagnostic trouble code (DTC), along with its status when the scanner shows one—such as active, confirmed, pending, stored, or permanent. If the scanner does not provide a usable status, record that it is unknown or unavailable. Save an export or screenshot if the tool supports it.
Step 2
Save the freeze-frame or operational snapshot
If available, save or photograph the snapshot tied to the fault before changing the vehicle state. Keep the displayed labels, values, units, code association, and capture time together.
- Engine speed (RPM)
- Engine load
- Coolant temperature
- Short- and long-term fuel trims
- Vehicle speed
- Intake-air temperature
- Fuel-system status
- Fuel pressure when available
Step 3
Capture live data for intermittent faults
When a fault comes and goes, save relevant live-data readings while the symptom is present. Note what was happening—such as idling, accelerating, or cruising—and repeat only under safe conditions.
General advice vs. vehicle-specific requirements: This is general capture advice, not a universal test procedure. Field availability, meanings, units, scanner coverage, and procedures vary by year, make, model, engine, code, and tool. Use the service manual for the vehicle-specific requirements, and treat codes as clues to investigate—not as diagnoses by themselves.
Safety boundary: Do not take risks to collect a reading. Brakes, steering, suspension, high-voltage hybrid or electric systems, and advanced driver-assistance systems can require specialized procedures and training. Stop and use a qualified professional when the service manual calls for it or the vehicle is unsafe to operate.
DIY interpretation
How to read common freeze-frame fields
Use these labels to describe the operating context captured with a code. The values are a point-in-time snapshot, not current or real-time data, and they should be read with the code, capture conditions, units, and vehicle service information.
- Engine speed / RPM
- Crankshaft speed at the moment the code was recorded [1]. Read it alongside the capture context—such as idle, acceleration, or cruising—rather than treating one RPM value as evidence of a failed component.
- Calculated engine load
- The controller’s calculated estimate of operating demand [1]. Acceleration, a hill, or light cruising can produce different context; the calculation is vehicle-specific and is not the same thing as throttle position.
- Engine coolant temperature
- Coolant temperature reported at capture [1]. Compare it with how long the engine had been running, ambient conditions, and the vehicle’s service information; one temperature reading does not prove a cooling-system or sensor failure.
- Fuel-system status
- The reported control mode, commonly an open-loop or closed-loop label, at capture [1]. Preserve the exact label and use the vehicle-specific definition instead of assuming that the status alone identifies a fault.
- Short-term fuel trim (STFT)
- The controller’s immediate fuel-delivery correction in response to air/fuel feedback at capture [1]. It is a context clue that should be compared with related data and vehicle-specific test guidance, not a standalone verdict.
- Long-term fuel trim (LTFT)
- A learned, longer-term fuel correction retained from earlier air/fuel feedback [1]. It describes controller history as well as the snapshot moment, so do not use it alone to name a failed sensor or part.
- Vehicle speed
- The reported road speed at capture [1]. The unit and source can vary; use it to reconstruct whether the vehicle was stopped, cruising, or accelerating when the code was stored.
- Throttle position
- The reported throttle opening at capture [1]. On electronically controlled vehicles it may not equal pedal position or calculated load, so interpret it with the other fields and the service information.
- Intake-air temperature
- The temperature of air entering the engine at capture [1]. Ambient temperature, heat soak, airflow, and the vehicle’s sensor strategy can affect the context; one value is not proof that the intake-air sensor failed.
A freeze-frame can be cleared, or a later failure can replace an earlier snapshot for some fuel-control or misfire situations [3]. Availability, calculations, labels, and units vary by vehicle, model year, engine, code, and scan tool. Do not apply a universal pass/fail threshold to any field here.
Diagnostic and safety boundary: These values are contextual clues, not a diagnosis or proof that a sensor, component, or other part failed. A snapshot alone also does not establish present vehicle safety. For a vehicle-specific conclusion, compare current data with the original snapshot and follow appropriate testing, service information, or a qualified professional’s guidance.
The separately named sourced freeze-frame research report was not present in this checkout. This guide therefore makes no report-derived claims and cites only the supporting references shown below.
Sources cited in this interpretation
Reading a record
This quick reference explains commonly cited labels and their general diagnostic role. It does not claim that the list is complete or mandatory, set pass/fail ranges, or replace vehicle-specific definitions from the service manual.
Quick reference
- Engine load
- A calculated measure of the engine’s operating demand at the snapshot; the calculation is vehicle-specific.
- %
- Short-term fuel trim
- The controller’s immediate fuel correction in response to air/fuel feedback at capture.
- STFT
- Long-term fuel trim
- The learned, longer-term fuel correction retained from prior air/fuel feedback.
- LTFT
- Engine coolant temperature
- The coolant temperature reported by the engine controller’s temperature circuit at capture.
- ECT
- Fuel pressure
- The fuel-system pressure reported for the snapshot; its measurement point and unit depend on the vehicle.
- varies
- Intake manifold absolute pressure
- The absolute pressure reported in the intake manifold at capture; use the vehicle’s unit and sensor definition.
- MAP
- Engine speed
- Crankshaft rotation speed at capture, reported as revolutions per minute.
- RPM
- Vehicle speed
- The road speed reported by the vehicle at capture; the displayed unit depends on the scan record.
- varies
- Timing advance
- The ignition-timing advance value reported for the snapshot; exact definition and units are vehicle-specific.
- reported
- Oxygen-sensor voltage
- Voltage reported by an oxygen-sensor circuit at capture; sensor type and vehicle strategy determine how to read it.
- V
- Temperature
- Degrees Fahrenheit / degrees Celsius
- °F/°C
- Percentage
- Percent
- %
Further reference
Anonymous worksheet
Diagnostic evidence record sheet
Use this worksheet to capture the scanner's report before you change the vehicle state. Your draft is saved only in this browser's local storage. It is not uploaded, sent to a server, shared with an account, or visible to other CrankKey users.
Safety first: Review urgent vehicle warning signs before recording diagnostic information.
Checking for a saved draft in this browser…
Record these values before clearing codes, disconnecting the battery, or beginning a repair.
Freeze-frame is a single snapshot of vehicle conditions captured when a diagnostic trouble code is detected—not a live or current reading, and not a diagnosis.
Field availability, units, and interpretation vary by vehicle and scanner. Record what the tool reports and leave unavailable fields blank.
Vehicle and capture context
Year
Not entered
Make
Not entered
Model
Not entered
Additional vehicle details
Not entered
Engine or powertrain
Not entered
VIN or last 8
Not entered
Mileage / odometer
Not entered
Scanner or software
Not entered
Capture date / time
Not entered
Conditions: idle / cruise / acceleration / other
Not entered
Diagnostic trouble code
Code
Not entered
DTC status: active / confirmed / pending / stored / permanent / unknown or unavailable
Not entered
MIL / warning-light state
Not entered
Available freeze-frame values
Engine speed / RPM
Not entered
Engine load
Not entered
Coolant temperature
Not entered
Short-term fuel trim (STFT)
Not entered
Long-term fuel trim (LTFT)
Not entered
Vehicle speed
Not entered
Intake-air temperature
Not entered
Fuel-system status
Not entered
Fuel pressure
Not entered
Live-data snapshot
Live readings are scanner- and vehicle-dependent contextual observations. They do not establish a diagnosis or component failure and are not a universal pass/fail test. Follow safe procedures and vehicle-specific service information.
Engine speed / RPM
Not entered
Coolant temperature
Not entered
Short-term fuel trim (STFT)
Not entered
Long-term fuel trim (LTFT)
Not entered
Intake-air temperature
Not entered
Manifold absolute pressure (MAP)
Not entered
Mass airflow rate (MAF)
Not entered
Observations
No observations entered
Diagnostic or repair attempts
None recorded
Diagnostic trouble codes are clues to investigate, not diagnoses by themselves. Keep the code, status, values, and capture context together.
Safety-critical work involving brakes, steering, suspension, high-voltage hybrid or electric systems, or advanced driver-assistance systems may require a qualified professional.