Triage trees
Symptom → system decision trees. Each leaf ends with: the static test to run, the manual page(s) to fetch, and applicable bulletins. Ask ONE narrowing question at a time to move down a tree — pick the question that best splits the remaining branches.
Trees encode the path; specs and procedures come from live fetches of the cited pages.
Tree 1: Rear noise (worked example of the character × correlation matrix)
Section titled “Tree 1: Rear noise (worked example of the character × correlation matrix)”Q1 — Character: whine/grind, knock/clunk, rattle/buzz, or click/tick? Q2 — Correlation: engine RPM, wheel speed, bumps, load transitions, or turning?
Knock/clunk, both turn directions, low-speed/paddock-only
Section titled “Knock/clunk, both turn directions, low-speed/paddock-only”→ Plate-LSD behavior. Clutch-type LSD; chatter at parking-lot speeds is often normal or oil/wear-related, not a broken part.
- Static tests: wheels-up backlash at the diff; note that a broken-in diff spins easily by hand unloaded — that alone is NOT wear.
- Fetch:
tunables/diff-plate-stacks.md(plate configs, broken-in vs worn guidance),maintenance/fluids.md(diff oil spec — verify live),maintenance/each-month/changing-diff-and-engine-oil.md. - Bulletins: 2025-10-07 Differential Rebuild Upgrade Kit, 2025-07-29 Lowered Differential.
- Cheapest-first order: oil spec/age check → backlash → plate stack inspection → rebuild kit.
Clunk on load transitions (on/off throttle), straight line
Section titled “Clunk on load transitions (on/off throttle), straight line”→ Chain slack, cush/sprocket interface, diff backlash, halfshaft CV lash.
- Static tests: chain tight-spot sweep through full rotation and suspension travel; wheels-up rotational lash at each halfshaft vs at the diff (localizes which joint).
- Fetch:
maintenance/each-weekend/clean-and-adjust-chain.md,maintenance/each-year/rebuilding-axles.md. - Bulletins: 2025-07-09 Upgraded Outboard CV Joint Hardware.
Click/tick correlated with wheel speed, worse under turning + load
Section titled “Click/tick correlated with wheel speed, worse under turning + load”→ Outboard CV joints under articulation, or side-loaded wheel bearing.
- Static tests: 12/6 and 3/9 rock at each rear corner (bearing); rotate wheel with halfshaft loaded/unloaded to isolate CV.
- Fetch:
maintenance/each-year/inspecting-wheel-bearings.md,maintenance/each-year/rebuilding-axles.md. - Bulletins: 2025-07-09 Upgraded Outboard CV Joint Hardware.
Whine/grind correlated with wheel speed
Section titled “Whine/grind correlated with wheel speed”→ Frequency-discriminate: once-per-wheel-rev (hub/bearing/tire), once-per-chain-rev (stiff link, damaged roller), multiple-per-rev (sprocket teeth).
- Static tests: chain sweep for tight spots; sprocket tooth inspection; bearing rock.
- Fetch:
maintenance/each-weekend/clean-and-adjust-chain.md,maintenance/each-year/replacing-chain-track-variable.md,tunables/gear-ratios-sprocket-changes.md.
Whine/grind correlated with engine RPM (any gear, incl. neutral revs)
Section titled “Whine/grind correlated with engine RPM (any gear, incl. neutral revs)”→ Engine/gearbox/primary side, not final drive.
Rattle/buzz over bumps
Section titled “Rattle/buzz over bumps”→ Suspension/chassis hardware, bodywork, heat shields, exhaust hardware.
- Static tests: weekend nut/bolt inspection pass; push down on each corner and listen.
- Fetch:
maintenance/each-weekend/inspecting-nuts-and-bolts.md. - Bulletins: 2025-11-03 Control-Arm Retaining Compound, 2025-11-04 Upgraded Spherical Bearing, 2026-01-16 Misalignment Spacer.
Tree 2: Shift faults
Section titled “Tree 2: Shift faults”Start at the manual’s own symptom index — fetch
maintenance/electronics-and-wiring/gcu-debugging.md and use its “Where to Start”
routing. Summary of the branches (fetch the page for the procedures):
Q1: Do BOTH paddles work sometimes? Does the compressor run? What does the AiM show for tank pressure?
| Symptom | Branch (on gcu-debugging page) |
|---|---|
| Both paddles dead AND compressor won’t run | Nothing Works (signal fuse → heartbeat LED → power-supply cap → pressure sensor fail-safe → Mega 2560) |
| One paddle direction dead | One Paddle Direction (wire swap → ground pin → filter cap bypass → wheel swap) |
| Both directions miss intermittently (false neutrals, missed shifts) | Missed/Incomplete Shifts: tank pressure first, then countershift setting, then mechanical |
| One direction weaker / sounds different | Asymmetric Shifts (valve block, Amphenol connector pins) |
| Missed up- OR down- but not both, incomplete engagement | Shift Linkage Mechanical (arm clearance, rod length/cylinder alignment) |
| Can’t find neutral engine-running | Clutch disengagement + technique (hold neutral, then pull direction paddle) |
| Erratic, no clear pattern | GCU water intrusion (daily water check!) |
| Compressor runs continuously / never / short-cycles | Compressor Issues (leaks → relay → MOSFET; drain-tank test separates sensor vs board vs compressor) |
| Limp mode / no blip / no cut (Gen2 DBW) | Speed Emulator → Clutch Switch → Gearshift Sensor Mimic, in that order |
| No blip (Gen1 cable) | Blip cylinder air supply + throttle cable |
- Key bisecting static test: Manual Pneumatic Shift Test (bypasses GCU; splits electrical vs pneumatic/mechanical in one test) — procedure on the gcu-debugging page.
- Second bisector: serial console at 115200 baud — paddle-press lines vs shift-completed lines tell you which half of the chain is lying.
- Fetch as needed:
maintenance/electronics-and-wiring/shift-harness.md(pin-level),maintenance/electronics-and-wiring/gcu-firmware.md(console access, versions). - Bulletins: 2025-09-12 Compressor TSB — check before condemning any compressor.
- Interval note: shift valve and compressor are four-event service items; overdue service masquerades as faults.
Tree 3: Electrical / voltage issues
Section titled “Tree 3: Electrical / voltage issues”Q1: Constant or load-dependent? Which loads (fans, fuel pump, compressor)? What does the dash voltage read engine-off vs idle vs 5000 RPM?
Voltage sags under load (e.g. fans on), recovers when load drops
Section titled “Voltage sags under load (e.g. fans on), recovers when load drops”→ Charging system: regulator/rectifier output, battery health, main power distribution connections.
- Static tests: dash/multimeter voltage at idle vs revs with loads staged on one at a time; voltage-drop test across main power connections and grounds.
- Fetch:
maintenance/electronics-and-wiring/main-harness.md(power distribution + diagrams),maintenance/suzuki-service-manuals.md(R/R and stator specs are Suzuki-side). - Bulletins: 2025-06-23 Battery (+) Wire Relocation.
Dead circuit / single subsystem dark
Section titled “Dead circuit / single subsystem dark”→ Fuse → connector → harness segment, in that order.
- Fetch:
maintenance/electronics-and-wiring/main-harness.md,maintenance/electronics-and-wiring/dash-harness.md. - Note: the compressor circuit is always hot via the ABS fuse regardless of ignition.
Dash alarm showing (oil pressure, water temp, oil health, clutch)
Section titled “Dash alarm showing (oil pressure, water temp, oil health, clutch)”→ Treat the alarm as instrumentation first, mechanical second — but never dismiss oil pressure without proof.
- Fetch:
at-the-track/aim-dashes-and-smartycams/dash-alarms.md(alarm meanings + thresholds), then the implicated system’s pages.
Intermittent everything / erratic behavior
Section titled “Intermittent everything / erratic behavior”→ Grounds, water intrusion (GCU and connectors), chafed harness.
- Fetch:
maintenance/electronics-and-wiring.md, gcu-debugging water-intrusion section.
Tree 4: Overheating
Section titled “Tree 4: Overheating”Q1: Overheats everywhere, or only in sessions/traffic? Gradual creep or sudden spike? Losing coolant?
Sudden spike
Section titled “Sudden spike”→ Airlock, failed hose/clamp, water pump. Stop running it; inspect for loss first.
- Fetch:
maintenance/each-year/changing-coolant.md(fill + bleed procedure),at-the-track/aim-dashes-and-smartycams/dash-alarms.md(water temp thresholds).
Gradual creep over a season
Section titled “Gradual creep over a season”→ Radiator fouling (open-wheel cars eat rubber and debris), coolant age.
- Static test: visual through-radiator light check; fin condition.
- Fetch:
maintenance/each-year/cleaning-radiator.md,maintenance/each-year/changing-coolant.md.
Only in traffic / low speed
Section titled “Only in traffic / low speed”→ Fan operation (also cross-check Tree 3 if fans drag voltage down), airflow.
- Static test: confirm fan cut-in temp on dash while stationary.
- Fetch:
maintenance/electronics-and-wiring/main-harness.md(fan circuit).
After maintenance / new engine
Section titled “After maintenance / new engine”→ Airlock from an incomplete bleed; verify before anything else.
- Fetch:
maintenance/each-year/changing-coolant.md(bleed procedure — fetch live).
Tree 5: Handling deviation from baseline
Section titled “Tree 5: Handling deviation from baseline”Q1: Deviation since when — after a change (setup, crash, curb strike), or gradual?
After a setup change
Section titled “After a setup change”→ Compare every touched parameter against the factory baseline before diagnosing hardware.
- Fetch:
tunables/factory-baseline-setup-guide.md, then the specific tunable page (tunables/alignment-and-ride-height.md,tunables/shock-adjustments.md,tunables/anti-roll-bars.md,tunables/diff-plate-stacks.md).
After contact / curb strike
Section titled “After contact / curb strike”→ Alignment check first; then inspect suspension hardware, rod ends, control arms.
- Static tests: string/plate alignment vs baseline; corner weights if available; visual on every rod end and spherical.
- Fetch:
tunables/alignment-and-ride-height.md,maintenance/each-weekend/inspecting-nuts-and-bolts.md. - Bulletins: 2025-11-04 Upgraded Spherical Bearing, 2025-11-03 Control-Arm Retaining Compound, 2026-01-16 Misalignment Spacer, 2025-07-23 Wide Rear Camber Plates.
Gradual deviation, no changes made
Section titled “Gradual deviation, no changes made”→ Wear items: shock gas pressure, tire heat cycles, plate LSD seating, bushings/sphericals.
- Static tests: shock pressure check; tire heat-cycle count; corner rock tests.
- Fetch:
maintenance/each-weekend/checking-shock-pressure.md,tunables/tires.md,maintenance/each-year/rebuilding-shocks-track-variable.md.
One-corner misbehavior (pulls, uneven wear)
Section titled “One-corner misbehavior (pulls, uneven wear)”→ That corner’s alignment, shock, bearing, or a bent component.
- Static tests: side-to-side comparison of camber/toe; swap components corner-to-corner where cheap (cheapest discriminating test).
- Fetch:
tunables/alignment-and-ride-height.md,maintenance/shock-diagrams.md.