HAX DrivePulse — User Manual

Meet your DrivePulse

DrivePulse is a solid-state instrument bar. It plugs into a Bluetooth OBD-II adapter in your car and shows live engine data across one to eight OLED screens — and reads your fault codes in plain English the moment the check-engine light comes on.

DrivePulse Quad, four lit gauges and two buttons

What you have

The screens — each a 128×64 OLED. Screen 1 (nearest the buttons) is the interactive display you drive the menus on. Screens 2–8 show whatever live data you assign them.
Two buttons — that's the entire interface. Marked 1 and 2 on the panel.
USB-C port — on the end wall. Power it from any 12 V USB adapter in the car.

What you also need

An OBD-II vehicle — effectively any car sold in the US from 1996, EU petrol from 2001, diesel from 2004.
A Bluetooth Low Energy (BLE) ELM327 adapter — the common $8–15 kind. (Classic-Bluetooth or Wi-Fi-only adapters will not work.)
A 12 V USB power source — a cigarette-lighter USB adapter is perfect.

Powering on. DrivePulse boots the instant it gets USB power — about one second, with the HAX ignition animation below. It reopens the exact screen you were on when it last lost power.

Startup screen. The HAX logo, an ignition sweep, and “FAULT SENTINEL / PROTOTYPE”. On multi-screen units each panel lights in sequence.

The two buttons

The entire interface runs on two buttons: NEXT and SELECT. Everything is a tap (press and release) or a hold (press and keep holding). Learn these four moves and you know the whole device.

Button 1 · move & change

Tap: Next item — steps through menus, cards, codes and sensors. Lists wrap around.
Hold: Fast-scroll a long list. On a live gauge, hold switches the view (number → bar → graph).
In editors: Tap = + one step, hold = − one step.

SELECT

Button 2 · choose & back

Tap: Pick / OK — open the highlighted item, confirm, or reset a value.
Hold: Go back one level. From most screens, hold returns you home.
In editors: Tap = change the step size, hold = save.

This same reference lives on the device under Main Menu › Help / About:

Help / About. The on-device cheat sheet, plus the firmware version.

The golden rule: tap SELECT goes in / confirms, hold SELECT goes back. tap NEXT moves along, hold NEXT does the “power” version of whatever screen you're on.

First-time setup & pairing

You pair your Bluetooth adapter once. DrivePulse remembers it by address and reconnects on its own every drive after.

Plug the BLE ELM327 adapter into the OBD-II port under your dash (driver's side, near the steering column).
Turn the key to ON (or start the engine). The adapter needs the car awake to answer.
Power up DrivePulse from a 12 V USB socket.
Go to Main Menu › Bluetooth › Find My Adapter and let it scan.
Pick your adapter from the list — then you're done, forever.

The adapter list

Likely OBD adapters are marked with a * and sorted to the top; the signal-strength bars on the right show which is closest. Tap NEXT to move down the list, tap SELECT to connect.

No PIN is ever needed — BLE adapters don't use one.

If it can't connect

You'll see Adapter Not Found. Almost always it's one of two things: the adapter isn't fully seated, or the key isn't ON. Fix that, then tap SELECT to try again.

The Bluetooth menu also has Reconnect, Adapter Info, and Forget Adapter (to pair a different one).

The home screen

Home is a carousel of big, glanceable gauge cards. Tap NEXT to slide to the next card; the page counter (2/5) shows where you are.

Speed card — **Big gauge card.** Icon, large value, unit, and a live status pill (MOVING).

RPM card — **The carousel** rotates through Speed, RPM, Battery, Coolant and Average MPG.

Getting around from home: tap NEXT next card · tap SELECT open the Main Menu · hold SELECT jump back to this home screen from anywhere.

Menu item	What it does
Live Dashboard	Real-time RPM / speed / coolant / battery on one screen.
Gauges	Focused single gauges: RPM, battery, boost/vacuum, fuel trims, 0–60 timer, since-last-erase.
Fuel Economy	Instant & average MPG, range estimate, tank setup.
Engine Codes	Read, understand and (carefully) clear trouble codes.
Smog Check	Are your emissions-readiness monitors complete? Check before an inspection.
All Sensors	Browse every live sensor your car reports (18 supported PIDs).
Trip Computer	Trip summary, peak records, reset.
Vehicle Info	VIN and readiness details from the ECU.
Bluetooth	Find, reconnect to or forget your adapter.
Settings	Units, alarms, display, extra screens — see section 10.
Help / About	The button cheat sheet and firmware version.

Reading fault codes

This is what DrivePulse is for. It watches the check-engine (MIL) status in the background. The moment your ECU turns the light on, it automatically reads the codes and tells you what they mean.

The alert

When the light comes on you get an unmissable ! CHECK ENGINE ! banner with the number of codes found. Tap SELECT to see the details, or hold SELECT to dismiss it for now.

Plain-English codes

Each code shows the number and what it means — P0301 → Cylinder 1 Misfire. Over 350 codes are described on the device (no phone or internet needed), with smart fallback decoding for anything rare. Tap NEXT to step through multiple codes; hold SELECT to go back.

(known fault) means an exact match; (general area) means it decoded the category of a code it doesn't have verbatim.

The Engine Codes menu

Item	Reads
Current Codes	Confirmed faults that turned the light on (Mode 03).
Pending Codes	Intermittent faults being watched, not yet confirmed (Mode 07).
Permanent Codes	Codes that only clear after the car re-verifies the repair (Mode 0A).
Fault Snapshot	Freeze-frame — the engine conditions captured when the fault hit.
Erase Codes	Clears codes and turns off the light. Two-step confirm.

Fault snapshot

The freeze-frame shows what the engine was doing the instant the fault was recorded — RPM, speed, coolant temp, load. Priceless for diagnosing intermittent problems.

No codes screen — **All clear.** No stored faults — a green light before a road trip or smog test.

Erasing codes — read this

Erasing is not repairing. Clearing codes turns the light off, but if the fault isn't fixed it comes back. Erasing also resets your emissions-readiness monitors — if you erase and drive straight to a smog check, you'll fail for “not ready.” DrivePulse warns you and requires a deliberate two-step confirm.

DrivePulse only ever reads data and uses the standard clear command. It cannot reprogram, tune, or damage your ECU.

Gauges & sensors

Any live value can be shown three ways. On a gauge screen, hold NEXT to cycle the view:

View	Looks like	Best for
Numerical	One big number + unit	Reading an exact value at a glance
Gauge / Bar	A bar or segmented tach that fills	Seeing where you are in the range
Live Graph	A scrolling line of the last ~minute	Spotting trends, spikes and drops

All Sensors lets you browse all 18 supported readings: engine load, coolant, fuel trims (B1), intake pressure, RPM, speed, ignition advance, intake air temp, MAF airflow, throttle, O₂ voltage, run time, fuel level, barometric pressure, battery voltage, ambient temp, and fuel rate. Tap NEXT to move between them.

Not every car reports every sensor. If your ECU doesn't support one, DrivePulse shows -- rather than a fake number, and battery voltage falls back to the adapter's own reading.

Fuel economy & trips

DrivePulse estimates fuel economy from live engine data and keeps a running average that survives power cycles.

Fuel Economy menu

Instant MPG	Right-now economy + a mini sparkline.
Average MPG	Rolling average, saved to memory.
Range Estimate	Distance-to-empty from fuel & economy.
Tank Size	Your tank capacity (for range).
Fuel Level	Set current fuel manually if needed.
Reset To Full	Tell it the tank is full now.

Trip Computer

Trip Summary	Distance and economy this trip.
Peak Records	Highest RPM, speed, temp; lowest volts.
Reset Trip	Start a fresh trip.

0–60 timer lives under Gauges — for honest bragging.

Accuracy. MPG is an estimate from MAP/MAF and load, not a fuel-flow meter reading (unless your car reports fuel rate). Use Settings › MPG Cal to trim it to your real tank-to-tank numbers.

Multi-screen displays

On 2- to 8-screen DrivePulse units, screen 1 stays your interactive display and screens 2–8 each show a live page you assign. Configure them under Settings › Additional OLEDs.

Aux RPM tach — **RPM Tach** — a segmented digital tachometer.

Aux core data quad — **Core Data 2×2** — four vitals on one panel.

Aux battery graph — **Live Graph** — here battery voltage over the last minute.

Aux vehicle status — **Vehicle Status** — BLE, ECU, MIL and battery at a glance.

For each extra screen you choose a page (what it shows) and, for the sensor pages, a view (number / gauge / graph):

Assignable page	Shows
Off / Blank	Screen off.
Vehicle Status	Link, ECU, check-engine and battery summary.
RPM / Speed / Coolant / Battery	That one value, in your chosen view.
Live Sensor	Any of the 18 sensors, in your chosen view.
Fuel Economy	Now + average MPG.
Fuel & Range	Fuel remaining and distance-to-empty.
Core Data 2×2	RPM, speed, temp, battery grid.
Trip Peaks	Session peak records.
HAX Logo	A static badge screen.

Why a Duo and up needs the little extra board. Every screen has the same fixed address, so 2+ screens can't share one cable directly — the built-in I²C multiplexer inside the case handles that for you. Nothing to set up; it just works.

Settings reference

Open Main Menu › Settings. Tap NEXT to move, tap SELECT to change the highlighted item (toggles flip; values cycle to the next option). Always finish with Save & Exit — that writes your choices to memory.

Settings top — **Settings.** Each row shows its current value inline.

Settings alarms — **Scroll down** for the alarm thresholds and tuning.

Setting	What it does	Options (tap SELECT to cycle)
Units	Opens the units sub-menu (below).	› submenu
Buzzer	Beeps for alerts and key presses.	ON / OFF
Alert LED	Lights the warning LED on alarms.	ON / OFF
Auto Alerts	Auto-reads codes when the light comes on.	ON / OFF
Flip Screen	Rotate the display 180° for mounting.	ON / OFF
Contrast	Display brightness.	40 → 240, steps of 40
Overheat	Coolant alarm threshold.	Off / 110 / 115 / 120 °C
Low Volt	Battery-voltage alarm.	Off / 11.6 / 11.8 / 12.0 V
Shift	Shift-light RPM (one beep crossing it).	Off / 5000 / 6000 / 6500 rpm
Check Rate	How often it polls the check-engine status.	0.8 / 1.0 / 1.5 / 2.0 / 3.0 s
Engine Size	Displacement, for the MPG estimate.	value editor
MPG Cal	Trim the economy estimate to reality.	60 → 140 %, steps of 5
Additional OLEDs	Assign pages to screens 2–8.	› submenu
Factory Reset	Erase all settings and restart.	action
Save & Exit	Write settings to memory.	action

Units sub-menu

Tap SELECT on any row to flip it. Units save automatically when you leave this menu.

Speed — mph / km/h
Temp — °F / °C
Distance — mi / km
Pressure — psi / kPa / bar
Economy — mpg / L/100km / km/L

Value editors (Engine Size, Tank Size, Fuel Level)

These use a slightly different button scheme:

Action	Does
Tap NEXT	Increase by the current step.
Hold NEXT	Decrease by the current step.
Tap SELECT	Change the step size (e.g. 1 → 0.1).
Hold SELECT	Save and exit the editor.

Alarms & alerts

Set an alarm once and forget it until it saves you. All three live in Settings.

Overheat — buzzer + LED when coolant crosses your threshold. The best cheap insurance against a blown engine.
Low Volt — warns of a dying battery or failing alternator before you're stranded.
Shift light — one crisp beep the instant you hit your shift RPM.
Check-engine — with Auto Alerts ON, the moment the light comes on you get the alert and the codes, automatically.

Silence it your way. Prefer no noise? Turn Buzzer OFF and keep the Alert LED on — or vice-versa.

Troubleshooting

Symptom	Try this
Won't find the adapter	Key ON, adapter fully seated, adapter is BLE (not classic-Bluetooth or Wi-Fi). Re-scan from Bluetooth › Find My Adapter.
Connected, but data says “--”	Engine off, or your car doesn't report that sensor. Start the car; try a different gauge.
Values freeze then recover	Normal with a slow adapter — the firmware auto-recovers. A better adapter smooths it out.
Screen upside-down for your mount	Settings › Flip Screen.
Display too dim / too bright	Settings › Contrast.
Extra screens blank	They doze after the car's been off a while — press a button or start the car to wake them.
MPG looks wrong	Set Engine Size, then trim with MPG Cal against a real tank of fuel.
Totally stuck	Unplug and replug USB. Settings survive; it reopens where you left off.

Drive safely. Configure and read DrivePulse while parked. Mount it low or on the A-pillar, clear of airbags and your sight line. It's built to be glanceable — big digits, high contrast — so a glance is all it ever needs. It is an accessory display, not a replacement for your car's instrument cluster or its warning lights.

User Manual