Infiniti QX80 and QX56 Rear Air Suspension Height Calibration with ELM327
New height sensor, struts or control unit, and now the rear rides too high or sags? You can store the standard ride height again yourself with an ELM327, a phone, and a lift or a jack.
On the Infiniti QX56 and QX80 (Z62), the rear air suspension has its own control unit. It remembers the standard ride height and which height sensor signal corresponds to it. When that stored data no longer matches reality, the rear end does its own thing: it jacks itself all the way up or sinks down.
Normally the dealer stores the standard height. Canfiti runs the same procedure through an ELM327 adapter and your phone. You’ll still need a lift, or at least a jack and stands, and some care.
When you need to calibrate
- After removing, reinstalling, or replacing the height sensor.
- After replacing the air suspension control unit.
- After rear suspension work, if the vehicle no longer sits at the right height.
A real case: a QX80 owner replaced the rear strut assemblies, and the air suspension went haywire. Either the rear was pumped all the way up, so the truck handled poorly and bounced over speed bumps, or it was dumped to zero. Neither independent shops nor the dealer could calibrate it. Adjusting the sensor mechanically didn’t help, and neither did a brand-new sensor. A calibration through Canfiti with a basic Bluetooth adapter fixed it.
What you need
- An ELM327 adapter. The QX80 owner used a basic Bluetooth one. BLE, Bluetooth Classic (Android only), and Wi-Fi all work; more on the adapters page.
- Canfiti 0.3.2 or newer, the version that introduced calibration.
- A lift, or a jack with solid stands, and level ground.
The procedure itself takes a few minutes: the compressor runs for a minute in the first stage, and the final stage takes two more.
Make sure the sensor is alive first
Calibration stores new values, but it can’t revive a dead sensor, as a QX56 owner pointed out in the discussion. Before you start, open “Data monitor” and check:
- “Signal voltage of vehicle height sensor”. The first number is the sensor’s current signal; the second is what’s stored in the unit. Load the cargo area or sit in the back seat, and the first number should change.
- “Period of time that signal from vehicle height sensor does not change”. If the vehicle is being driven and this keeps climbing, the sensor signal may be stuck. Check the sensor and its wiring.
- “Voltage of air levelizer control module”, the unit’s supply voltage.
The “E-SUS unit” screen
On the main screen, tap the E-SUS card (“Air levelizer control module”). The screen has three sections:
- “Active test”: manual control of “AIR COMPRESSOR”, “EXHAUST SOLENOID” (bleeds air), and “WARNING LAMP” (the CK SUSP light on the dash).
- “Data monitor”: compressor, valve, and lamp status, voltages, ride height, and engine status.
- “Work support”: an “Alert” card with the instructions and three calibration buttons, “CLEAR HEIGHT INI”, “ADJUST HEIGHT INI”, and “STANDARD HEIGHT LEVEL”.
Active tests are useful on their own
“Active test” lets you check the system piece by piece. Turn on “AIR COMPRESSOR”: its status in “Data monitor” switches to ON, and you should hear the compressor run. If the status says ON but the compressor is silent, the problem is the compressor or its circuit. “EXHAUST SOLENOID” vents air and the rear drops, which shows the valve works. One reader confirmed the compressor and lamp tests work on his vehicle.
When you’re done, put everything back: at rest, the compressor, valve, and lamp are all off. At the bottom of the screen is the unit’s number on the “ECU part number” card; “Not connected” there means no link to the unit.
Calibration: three stages
| Stage | Vehicle | Tap | Wait | Done when |
|---|---|---|---|---|
| 1. Clear height | in the air, engine running | “AIR COMPRESSOR”, then “CLEAR HEIGHT INI” | compressor at least 60 s | CK SUSP on |
| 2. Unloaded height | still in the air | “ADJUST HEIGHT INI” | — | CK SUSP off |
| 3. Standard height | on its wheels | “STANDARD HEIGHT LEVEL” | at least 120 s | height −15 to +15 mm |
Stage 1. Clear the height setting
- Raise the vehicle so that no tire touches the ground. The app reminds you before clearing.
- Start the engine. In “Data monitor”, the engine status line should read RUN.
- Under “Active test”, turn on “AIR COMPRESSOR” and wait at least 60 seconds.
- Turn “AIR COMPRESSOR” off.
- Under “Work support”, tap “CLEAR HEIGHT INI”.
The stage is done when the CK SUSP light is on. If it went out, repeat the stage from the start.
Stage 2. Set the unloaded height
With the vehicle still in the air, tap “ADJUST HEIGHT INI”. The stage is done when the CK SUSP light goes out. If it stays on, repeat.
Stage 3. Set the standard height
- Lower the vehicle completely: lift all the way down, full weight on the wheels. The app reminds you of this too.
- Tap “STANDARD HEIGHT LEVEL” and wait at least 120 seconds.
The stage is done when “Vehicle height recognized by air levelizer control module” in “Data monitor” reads between −15 and +15 mm (about ±0.6 in).
Without a lift
The in-app instructions call for all four wheels in the air. A QX80 owner without a lift jacked up only the rear left wheel, where the height sensor is, and the calibration went through. That’s one owner’s experience, not the factory procedure.
How to tell it worked
- “Vehicle height recognized by air levelizer control module” is between −15 and +15 mm.
- “Completion of the standard vehicle height setting” reads “Completed”, not INCOMPLETE.
- The CK SUSP light is off.
- After a drive, the rear sits level, neither jacked up nor sagging.
If it didn’t work
- The light went out during stage 1: repeat the whole stage, including at least 60 seconds of compressor.
- The light is still on after stage 2: tap “ADJUST HEIGHT INI” again.
- Height is out of range: make sure the vehicle has its full weight on the wheels and the lift is all the way down, then repeat “STANDARD HEIGHT LEVEL”.
- “The unit is not responding”: check the ignition and the adapter connection.
- The sensor voltage never changes: it’s the sensor or its wiring, and calibration won’t help.
Safety
- Work only on a lift or jack stands.
- Don’t run the compressor longer than necessary, and switch it off after a test.
- “EXHAUST SOLENOID” vents air and the rear comes down. Make sure nobody is under the vehicle before you use it.
- Everything is done in software and is reversible: if something goes wrong, run the calibration again.
The calibration is confirmed by a QX80 Z62 owner, and the E-SUS screen also works on the QX56 Z62. More on the air suspension page and the QX80 and QX56 Z62 page.