Fault Tree: No Crank / Clicks

If the starter doesn’t turn the engine, treat it as a power/ground/control problem first. Don’t jump to a starter until you confirm voltage drop and control signals.

Quick triage & tools

  • Scan first: read codes (all modules if you can) + live data that matches the symptom.
  • Power basics: battery voltage (resting + while cranking) and quick fuse checks before deep dives.
  • Have ready: basic scan tool, multimeter, and a way to confirm the symptom (road test / idle test).

Tip: if a step says “check wiring”, use Wiring diagrams basics → and Voltage drop testing →

What you need (minimal)

  • Multimeter (or a decent test light).
  • Basic scan tool (helpful for checking immobiliser / PRNDL / clutch switch inputs on some cars).

Related deep-dive: Voltage drop testing →

Decision flow

  1. Confirm the symptom
    • Single click (relay/solenoid) vs rapid clicking (low voltage) vs dead silent (no control/power).
    • Dash lights dim hard when you try to crank? That’s a big clue.
  2. Battery state at rest
    • < 12.2V → charge the battery first, then retest.
    • 12.4–12.8V → proceed.
  3. Battery voltage while attempting crank
    • Drops below ~9.6V → battery weak, bad connection, or starter drawing too much.
    • Stays above ~10V but no crank → likely a control circuit / starter / ground issue.
  4. Terminal + ground inspection (5-minute check)
    Clean/tight terminals, check the body ground strap and engine ground. A loose ground can mimic a dead starter.
  5. Voltage drop test the crank circuit
    • Positive side (battery + to starter B+) should typically be low drop under load.
    • Ground side (starter case to battery -) should also be low drop.
  6. Starter control signal (solenoid trigger)
    • 12V present at the solenoid trigger when key is in START → control circuit is working; suspect starter/solenoid or power feed.
    • No 12V → trace upstream (relay, ignition switch, clutch/neutral switch, immobiliser).
  7. PRNDL / clutch switch / neutral safety
    Try starting in Neutral (auto), press clutch hard (manual), or check scan data for clutch/neutral input if available.
  8. Immobiliser / key authorisation
    Some cars allow crank with immobiliser active, others block the starter relay. Look for security light behaviour and related body/cluster codes.
  9. If you have good power + good grounds + 12V trigger and still no crank
    Starter/solenoid is the prime suspect. Confirm the engine isn’t seized (turn crank manually if safe) before replacement.

Related flows

Print / save checklist

Tick these off as you work. If you need to hand this to a mechanic, print it as a short job card.

  • Freeze-frame captured / conditions noted
  • Battery voltage checked (resting + cranking)
  • Basic visual checks (hoses, connectors, grounds, fuses)
  • One test at a time (don’t change multiple variables)
  • Confirm fix by reproducing the original condition
Print / Save as PDF Back to symptom selector

What to do next

Use the links below to deepen the test you’re about to perform, cross-check related codes, or jump to a faster symptom-led flow.

Find another symptom flow Jump to the symptom selector to locate the closest decision tree. Workshop Guides Deep-dive how-to tests: voltage drop, wiring diagrams, smoke testing, fuel pressure and more. Diagnostic Codes Look up DTC meanings, common causes, and related checks. AI Tools Use AI assistance to summarise symptoms, plan tests, or sanity-check a diagnosis.

Related fault trees

Symptom selectorCrank/no-startBattery/charging