On an Infiniti Q50, clicking during start points to a weak battery or poor connections; check voltage, clean terminals, and test the starter circuit first.
That sharp click when you press the Start/Stop button tells you the starter circuit tried to wake up but didn’t get the juice or the signal it needed. The good news: most no-crank clicks trace to simple power or connection faults you can confirm in minutes. This guide gives clear checks, values, and next steps that work on every Q50 trim and year.
Infiniti Q50 No-Start With Clicking — Quick Diagnosis
Work top-down: power, signals, then the starter itself. You’ll need a digital multimeter, a 10–12 mm wrench, and light. If you’re in a tight spot (like a fuel station), jump to the step-by-step flow below and follow it in order.
Common Symptoms, Likely Causes, And Fast Checks
| Symptom You Hear/See | Likely Cause | Quick Check / Fix |
|---|---|---|
| Rapid, repeated clicks; dash lights flicker | Low battery or high resistance at terminals | Measure resting voltage (≥12.4 V). Clean/tighten posts; try jump start; recheck. |
| Single heavy click, no crank | Starter solenoid contacts or starter motor | Battery good? Tap starter lightly, retest. If it cranks once then stops, suspect starter. |
| Click only in Park; starts in Neutral | Range/PNP switch misread | Hold brake, shift to Neutral, try start. If it works, inspect range sensor alignment. |
| No crank; “Key” or “I-Key” message | Intelligent Key battery low or RF interference | Hold fob to the Start/Stop button and try again; swap fob battery. |
| Slow labored crank then click | Weak battery or poor chassis/engine ground | Check voltage drop on ground straps while cranking; clean frame and engine grounds. |
| Intermittent starts; random click | Loose main cable, corroded fuse link, or relay | Inspect positive lead to fuse box/starter; reseat starter relay; test continuity. |
| Dead silence, then sporadic click | Brake switch or start button signal issue | Confirm brake lights glow; press pedal hard; scan for BCM codes if available. |
The Fast Flow: From Battery To Starter
Step 1 — Verify Battery Health
Pop the hood and put a meter on the posts, not the clamps. Resting voltage should land near 12.6 V on a fresh, fully charged unit. Below ~12.4 V often triggers rapid clicks. Try a boost. If the engine cranks normally with a jump, you’ve confirmed a supply issue, not a starter failure.
Step 2 — Eliminate Terminal And Cable Resistance
White/green crust or loose clamps block current. Remove the negative clamp first, then positive. Clean both posts and the inner faces of the clamps until shiny. Refit snugly. Follow the positive lead to the under-hood fuse box and the starter feed; check that the nut on each stud sits tight.
Step 3 — Try Neutral And A Second Key
Hold the brake, shift to Neutral, and press Start. If it cranks, the transmission range sensor needs attention. If you see an I-Key warning, touch the fob to the Start/Stop button and retry; Q50 accepts that fallback even with a weak fob cell (Infiniti documents this behavior: see touch the Start/Stop button with the Intelligent Key).
Step 4 — Listen For The Click Pattern
Rapid machine-gun clicks scream “low voltage at the solenoid.” A single thunk points at the starter drive or the solenoid contacts. If you’ve confirmed a healthy battery and clean connections yet still get a single click, move to the starter checks.
Starter, Solenoid, And Grounds
Where The Click Comes From
The solenoid is a small high-current switch riding on the starter. It pulls in when the ECM commands crank. If supply sags, it pulls in and drops out in a loop, making those rapid clicks. If supply is steady but the internal contacts are pitted, you hear one loud click and nothing turns.
Accessing The Starter Safely
Park on level ground. Set the parking brake. If you can access the starter body, a light tap on the housing while a helper presses Start can free sticky brushes once or twice. That’s a short-term test, not a repair. Replace a starter that needs tapping.
Ground Straps Matter
The engine and body must share a low-resistance path. Look for braided straps from the engine to the frame and from the battery to the body. Clean both ends and retighten. A weak ground gives slow cranks, warm cables, and—yes—clicks.
Signals And Security: When Power Is Fine
Intelligent Key, RF Noise, And Start Authorization
If you see an I-Key or Key System message and the battery checks out, rule out fob issues first. Replace the coin cell and try again. Strong radio noise near some buildings and accessories can confuse the signal. Nissan/Infiniti issued guidance noting that nearby devices can interfere; if symptoms vanish in a different spot, that’s your clue (see Intelligent Key interference bulletin).
Brake Switch And Range Sensor
The car needs to see a pressed brake and Park/Neutral before it will crank. If the brake lights don’t illuminate, the start request may be ignored. If it only cranks in Neutral, adjust or replace the transmission range sensor.
Start Relay And Fuse Links
Listen in the under-hood fuse box as a helper presses Start. You should hear a crisp relay tick. No tick points to control-side issues; a tick with no starter action points back toward power delivery or the starter itself.
Step-By-Step Checks With Target Readings
These numbers are safe general targets for a healthy gasoline V6 in this platform. They help you separate supply problems from component faults.
Test Values That Pinpoint The Fault
| Test | Target Value | What It Tells You |
|---|---|---|
| Battery at rest | ~12.6 V (≥12.4 V usable) | Low reading hints at discharge or aging cells. |
| Voltage while cranking | >9.6 V | Drop under load means weak battery or high resistance path. |
| Charge voltage (idling, lights on) | ~13.8–14.7 V | Low output points to alternator or wiring faults. |
| Positive cable drop (battery + to starter stud) | <0.5 V during crank | Higher drop signals corroded terminals, bad cable, or loose nut. |
| Ground drop (starter case to battery −) | <0.2–0.3 V during crank | Higher drop points to poor engine/body grounds. |
| Starter relay output | Battery voltage at relay out during crank | No voltage with a command means relay/wiring/BCM path fault. |
When It’s A Known No-Crank Pattern
Some cases set a message and store specific codes. Nissan/Infiniti documented a no-crank condition with I-Key messages and range-sensor-related codes. A dealer can read B-codes like B2604 and confirm the path. You can browse a public copy of a related bulletin here: engine will not start bulletin.
What To Try Before A Tow
Two-Minute Rescue Steps
- Clean and tighten both battery terminals. Don’t forget the small accessory leads.
- Shift to Neutral and retry the start.
- Hold the fob to the Start/Stop button and press firmly on the brake.
- Try a known-good jump pack; if it cranks, plan battery testing or replacement.
Signs You’ve Found The Culprit
- Cranks fine after a jump: supply issue or failing battery.
- Starts only in Neutral: range sensor path.
- Single heavy click with good voltage: starter assembly.
- Rapid clicks with dimming cluster: high resistance at posts or weak battery.
Costs, Parts, And Time
Battery replacement runs fast and often solves the click-no-crank pattern. Starters take more time due to access and heat shields. Grounds and cable ends are low-cost and fix many intermittent cases. A scan and basic meter work keep you from throwing parts at the car.
DIY Or Shop?
If you have a meter and a jump pack, you can do the checks above curbside. For BCM codes, range sensor alignment, or starter replacement, a shop visit saves guesswork. If your battery is under three years old and fails a load test, ask for a warranty claim.
Prevention So The Click Doesn’t Come Back
- Load-test the battery at least once a year, sooner if cranks slow.
- Clean and protect terminals at each oil change.
- Keep a compact jump pack in the trunk.
- Replace the fob coin cell once a year; it’s cheap and avoids I-Key drama.
- After any engine work, recheck that grounds are tight and clean.
Talk To Your Mechanic With Clarity
Describe the click pattern, dash messages, and what fixes you’ve tried. Share voltage numbers if you recorded them. Ask for a voltage-drop test across the main cables and a starter draw check. That single request separates a quick, clean fix from guess-and-replace.
Recap You Can Act On
Most click-no-crank events come down to low voltage at the starter. Prove the battery, clean the paths, and confirm the control signal. If supply is solid and it still only thunks, the starter assembly is next on the list. If the cluster flashes I-Key messages, use the fob-to-button trick and work the signal side before you order hard parts.
Helpful Official References
Infiniti’s own materials point to two quick wins you can try in the driveway: touching the fob to the button when the fob battery is weak (touch the Start/Stop button with the Intelligent Key) and checking for I-Key-related no-crank bulletins when messages show up (engine will not start bulletin). Use those along with the tests above to zero in fast.