Use Cases

EV owners who want insight without a dealer visit. Professionals who need reports their customers can act on. Two different tools inside one app.

iPhone & iPad — For EV owners and enthusiasts

Bluetooth LE OBD adapter. No tools. No appointment. Works in a car park. These three are example scenarios showing how the tools work, not customer results.

Example scenario · 01

Pre-purchase battery health check

Buying a used Jaguar I-Pace. Seller claims "perfect battery." You have 20 minutes.
The used EV market has a battery transparency problem. State of charge is visible on the dash, but state of health — the true measure of how much capacity the battery has lost — is not. Dealers rarely volunteer it and most buyers have no way to check.

With a Bluetooth LE adapter and EvmetricsOBD with Pro, you can read the BMS directly before signing anything.
  • 1 Plug a Bluetooth LE ELM327 adapter into the OBD port under the dashboard. Turn ignition on (not engine start).
  • 2 Open EvmetricsOBD on iPhone. Select Jaguar I-Pace template. Tap Connect — pairs automatically.
  • 3 Go to Health → State of Health. The app queries the BECM (7E4) directly and returns SoH as a percentage of original factory capacity.
  • 4 Check the cell voltage spread in the battery readings. It should be tight at rest (the real I-Pace below read 0.01-0.03 V). A large spread indicates cell imbalance.
  • 5 Run a DTC scan. Any stored fault codes, especially HV battery codes such as P0A80, appear with their fault names, attributed to the ECU that reported them.
  • 6 Tap Generate Report. Share the HTML report with the seller or keep it for your records. For a one-page summary of the battery alone, export the Battery Health Report PDF from Health: state of health, capacity, cell voltage spread, module temperatures and isolation resistance, all from the car's own BMS.
In about 10 minutes you have state of health, cell balance and any stored codes from the car's own BMS: evidence to negotiate with, or a reason to walk away.
Hardware needed: a Bluetooth LE ELM327 adapter (Vgate iCar Pro, Veepeak BLE+, Carista). Budget about $30-$45 or £20-£35. Classic Bluetooth adapters don't work on iPhone. Health, the DTC scan and reports need EvmetricsOBD Pro.
Example scenario · 02

Charge curve logging during a session

I-Pace owner. Noticing DC fast charging feels slower than it used to. Is the taper starting earlier?
EV charging curves taper as the battery fills — that's normal. What's not normal is a taper that starts significantly earlier than it should, or a curve that looks different from what the manufacturer published. The Charging Graph tool plots active power (kW) against SoC (%) in real time, building a permanent record of every session.
  • 1 Connect OBD dongle at the DC charger. Select Charging Graph category on the Dashboard tab.
  • 2 The app polls HV voltage, HV current and SoC from the BECM every few seconds.
  • 3 Watch the curve build. Note the SoC at which power starts to taper — typically above 80% on a healthy pack.
  • 4 Compare across sessions over time. A taper that creeps earlier across weeks may indicate emerging thermal management issues.
If the taper is starting earlier than it used to, you have a dated record to show the dealer rather than a feeling.
Example scenario · 03

Small EV fleet health checks with an iPad

Fleet of 8 I-Pace company cars. Monthly battery health reporting needed for lease resale planning.
Fleet managers need reliable, repeatable health data across multiple vehicles. The iPad's large screen makes it ideal for side-by-side comparison while walking a car park, and the Diagnostic Report export gives a consistent monthly record per vehicle.
  • 1 Each vehicle gets a 5-minute scan: SoH, SoC, cell voltages, DTC check. The app remembers the last Bluetooth device per vehicle profile.
  • 2 Generate and export a Diagnostic Report per vehicle as an HTML file.
  • 3 Compare SoH trends month-on-month. Identify vehicles declining faster than expected before they become a lease penalty problem.
Vehicles losing health faster than the fleet average stand out early enough to raise under warranty before lease return. State of health, Garage and reports need EvmetricsOBD Pro.
Real investigations

Real cars: Jaguar I-Pace and XF

Our own cars and captures, worked through with the Workshop checklists. Some are still open, and we correct them when the evidence changes.

Real car · Case 01

Degraded Pack, Dead Module Sensors & Warm A/C

2020 Jaguar I-Pace EV (185k km). Range feels down and A/C stopped getting cold. No warning lights on the dash.
Three stories from one set of scans: a degraded HV pack, compromised thermal sensing and an A/C that won't cool. Our early scans showed no codes because our reports weren't yet reading the battery module's own; correlating the live OBD channels showed all three. A later third-party scan found P1B48 active, consistent with the H441 recall.
  • 1 Capacity vs Cell Balance: Capacity Health settled flat at 70% across all scans, while Cell Voltage Spread remained tight (0.01–0.03V). This is uniform aging, not a single weak cell: the profile behind the I-Pace HV battery recall.
  • 2 Compromised Thermal Sensing: Several per-module temp sensors read impossible values (one stuck at -15°C, another flapping wildly to -216°C) while the pack's average sat at a sane 16°C. These are blind spots in the thermal safety net.
  • 3 Warm Cabin, Blower Flat Out: The evaporator stayed at about 20°C and vents blew 17-24°C with the blower at 7000 RPM, and the rear-right duct ran 4-6°C warmer than rear-left on every scan. The refrigerant reading we first relied on turned out not to be a real sensor, so a low charge is the first, cheapest check, then airflow and blend doors.
The pack and sensor findings gave the owner a data-backed reason to push for a warranty/recall assessment, instead of a simple "monitor it" outcome. The A/C needs its own check, starting with the refrigerant charge.
Read full case study →
Real car · Case 02

Hot No-Start After 30 Mins — Oil Hot, Coolant Cold

2019 Jaguar XF (2.0 Ingenium petrol). Drives normally for ~30 minutes, starts knocking audibly, then won't restart once hot. Only a "coolant level low" warning.
The temperature gauge hid the overheat. The coolant sensor read low (60°C) even as the oil cooked to 100°C. That divergence is the classic signature of coolant not circulating. Correlating the channels exposed the fault where standard gauges and DTC scans found nothing.
  • 1 Monitor Thermal Divergence: Lined up side-by-side, engine oil rocketed to 100°C (full operating temp) while engine coolant maxed out at 60°C (~30°C below normal). Heat in the block wasn't reaching the coolant sensor.
  • 2 Correlate with Warnings: The "coolant level low" warning (without an overheat light) pointed at low coolant, and possibly an airlock leaving the sensor in a vapour pocket reading cold.
  • 3 Assess Engine Stress: The audible knock after 30 mins of slow driving was the signal to assess thermal damage now, not later.
  • 4 Diagnostic Escalation: Stop driving it hot. Run integrity gates (compression, leak-down, combustion-leak) to check for thermal damage before throwing parts like a thermostat or water pump at the circulation issue.
Diagnosis confirmed coolant leaking into the gearbox through a failed oil cooler, the source of the milky coolant in the expansion tank. The gearbox, oil cooler and pipes were replaced and the cooling system flushed.
Read full case study →
Real car · Case 03

Crank-No-Start with Dead Headlights & Signals

2020 Jaguar XF (Diesel). Engine cranks but never catches, whilst headlights and indicators are totally dead. Tempting to blame one common electrical cause.
A dramatic symptom (dead lights) can look related to a no-start when it's actually a second, independent fault. Working the scan and the physical evidence together separated a likely mechanical timing failure from a separate lighting fault.
  • 1 Rule Out Total Power Loss: The BCM is alive. Lock/unlock still flashes brake lights and the hazard switch produces a rapid audible cue (hyperflash warning) even though external indicators are dead.
  • 2 Rule Out the Battery: The initial scan showed 11.4V at the battery, so it really was flat. Swapping it left the faults present, moving the diagnostic downstream.
  • 3 Isolate the Electrical Fault: The selective failure (dead indicators/headlights but working brake lights) points at a shared exterior-lighting feed, fuse, or BCM output driver, not a dead battery or main earth.
  • 4 Diagnose the Mechanical No-Start: The fast, free cranking with almost no compression and a camshaft seen static while cranking point to a snapped or jumped timing chain, which an independent specialist also diagnosed. A compression test would confirm it. The lighting fault is a separate problem.
Repair is ongoing, so the final outcome remains TBD.
Read full case study →
JLR bulletin · Walkthrough

No Cold Air — I-Pace A/C Compressor Pipe Leak

Jaguar I-Pace with the A/C blowing warm. JLR Technical Bulletin JLRTB02109NAS1 covers a leak on the A/C compressor inlet/outlet pipes.
"A/C not cold" on an EV can point at half a dozen systems — refrigerant charge, compressor, condenser, or the shared battery thermal management (BTMS) loop. This bulletin points at something simpler: a leak at the compressor's own pipe unions, caused by low weld quality on early-build pipes.
  • 1 Leak-Check the Compressor Pipes: Confirm the A/C is inoperative and trace any refrigerant leak to the compressor's HP and/or LP pipe unions before condemning the compressor itself.
  • 2 Follow the Bulletin, Not Habit: JLRTB02109NAS1 requires both the HP pipe (T4K19677) and LP pipe (T4K19719) to be renewed as a pair, even when only one is found leaking — the second weld is the same low quality.
  • 3 Work Through the Access Path: Recover the refrigerant, remove the front EDU for access only, reposition brackets and harness, and disconnect both sensor connectors before the pipes come out.
  • 4 Gate: Front Alignment Only: Subframe and front lower arm fasteners are disturbed for EDU access, so check and correct front wheel alignment — rear alignment, if ever needed, is separate work outside this bulletin.
The bulletin's fix: both compressor pipes renewed as a pair, the system evacuated and recharged, and front wheel alignment corrected, leaving no second weld of the same quality waiting to fail.
Read the walkthrough →
Real car · Case 04

Airbag Light Five Minutes In — Airbags Off for the Rest of the Drive

Jaguar XF, MOT due. The SRS lamp stays off at key-on and comes on after ~5 minutes — of driving, or just the engine running. While it's lit, at least one restraint stage is disarmed. A live investigation, documented before the first part is bought.
An SRS lamp isn't a sensor reading — it's the restraints module latching a failed self-test on a firing circuit, and failing safe by taking that stage offline. Three very different faults produce the identical lamp — supply, comms, or a real squib-circuit break — and here the onset timing does half the triage before a scanner is even plugged in.
  • 1 Read the Onset as Evidence: The lamp passes its key-on prove-out and only lights minutes into running — a marginal circuit failing warm under continuous monitoring, not a hard break latched at self-test. No cluster tamper, and the fault reproduces on demand.
  • 2 Use the Standstill Discriminator: The engine running is enough — the car doesn't need to move. That points away from movement-gated faults (clock spring, seat travel) and keeps thermal drift and charging-voltage drift firmly on the table.
  • 3 Baseline the Supply Past Minute Five: Rested battery, then control-module voltage (PID 0142) logged through and beyond the onset window with the engine running — an alternator wandering out of the 13.8–14.8 V band is a classic delayed-lamp cause, and it costs nothing to test.
  • 4 Then Ask the Restraints Module Directly: Mode 03 is often quiet for SRS — the B-codes live in the module. UDS to the JLR RCM (header 737) and occupant module (752) splits lost-comm (U0151-family) from a named squib-circuit fault — behind the safety gate: battery off, capacitor wait, never probe a squib live.
Investigation open: the onset triage is done and the re-test protocol is defined — nothing counts as fixed until it survives minute six, at a standstill and on the road. The case study will be updated when the scan names the circuit.
Read full case study →

iPhone & iPad

$8.99 once on the App Store, with optional Pro at $20.99 a year. Needs a Bluetooth LE or Wi-Fi ELM327 adapter.

Join the public beta on TestFlight → Coming to the App Store

Mac

In progress — a dedicated macOS build with wired USB support, to be sold from store.vladalexa.com. It will work with wired FTDI or CH340 USB ELM327 adapters.

macOS (arriving in 2027) →