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Results are grouped by useful content—not by paid placement or guessed parts. Describe the symptom naturally; IAR recognizes common alternate wording while keeping exact codes and vehicle details precise.
Your available vehicle context is included where the destination supports it. AI guidance stays separate from verified IAR source records.
Separate fuel, spark, compression, timing, and security-system faults with a test-first process.
IntermediateUse the first starting split—cranks or does not crank—to choose the correct electrical, authorization, fuel, ignition, or mechanical diagnostic path.
beginnerSeparate a missing lamp or changed circuit load from socket, wiring, switch, module, hazard, and control evidence before replacing a flasher or lamp.
beginnerReduced braking, unusually long stopping, or a vehicle that will not stop normally is a stop-driving condition. Secure the vehicle first, then separate hydraulic, assist, friction, mechanical, and control-system evidence with qualified service information.
professional recommendedAn EVAP code identifies a monitored vapor-control condition, but the useful next test depends on whether the evidence points to a leak/sealing fault, purge-flow fault, electrical circuit fault, or an incomplete monitor.
intermediateSeparate missing ignition, fuel delivery, control, synchronization, and mechanical evidence after the engine is confirmed to crank.
Test-first procedureUse warning behavior, scan context, cylinder pattern, and controlled contribution evidence to separate ignition, fuel, air, and mechanical branches.
Test-first procedureSeparate start-request, interlock, cable, ground, solenoid, and starter-motor evidence before bypassing the circuit or replacing the starter.
Test-first procedureCheck whether the vehicle is replenishing electrical energy under its intended operating strategy instead of applying one universal voltage rule.
Test-first procedureSeparate vibration caused by brake application from a shake that follows road speed before choosing a brake, wheel, tire, hub, or suspension path.
Test-first procedureInvestigate key-off battery drain only after the vehicle has entered its correct sleep state and the evidence is preserved.
Test-first procedureCompare operating pattern, temperature data, and airflow evidence without applying a universal gauge, infrared, or fan rule.
Test-first procedureThe starting system must authorize the request and deliver high current long enough to rotate the engine. A no-crank condition is different from an engine that cranks normally but does not run.
System guideThe fuel system stores and meters fuel under controlled conditions. A no-start, lean code, odor, or hesitation can involve supply, command, air measurement, electrical control, mechanical condition, or vapor management.
System guideThe engine turns stored fuel energy into controlled torque. Good diagnosis separates a combustion problem from a mechanical, control, mounting, or support-system problem before parts are removed.
System guideElectrical diagnosis follows the circuit and the evidence. A module-related code can be caused by supply, ground, wiring, communication, input, output, configuration, or the module itself.
System guideIAR does not passively record this search. Save feedback only if you want a local note that you can export later for editorial planning. VIN-like vehicle identifiers are redacted before local save.