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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.
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Electrical 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 guideThe charging system supports electrical loads and restores energy to the battery. Modern output can change intentionally, so one voltage reading does not automatically prove an alternator is good or bad.
System guideThe steering system changes wheel direction and returns road forces to the driver. Pull, vibration, looseness, and heavy steering should be separated from tire, brake, suspension, alignment, and road-surface effects.
System guideSeparate airflow, control, compressor-command, heat-rejection, refrigerant-circuit, and electrical concerns without venting refrigerant or guessing a charge.
professional recommendedClassify whether the engine stalls at idle, under load, during deceleration, immediately after starting, or with a broader electrical power loss before choosing a test path.
intermediateSeparate battery state, mechanical drive, cable loss, alternator output, sensing, control strategy, and vehicle-load concerns before replacing the alternator.
intermediateAn oil-pressure warning can represent actual lubrication-pressure loss or an electrical/sensor reporting fault. Because real pressure loss can damage an engine quickly, operation safety comes before diagnosis.
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.
intermediateUse the timing, affected circuits, electrical load, and vehicle state to separate a charging, connection, control, or individual lighting fault.
intermediateA pedal that suddenly feels hard or requires much more effort can indicate loss of brake assist, a vacuum/electrical control concern, or another braking fault. Secure the vehicle and verify the exact assist system before driving or replacing parts.
professional recommendedA sudden loss of steering assist, heavy steering, or a steering control change is a safety-critical handling problem. Stop safely and separate assist supply, electrical/control, hydraulic, tire, and mechanical evidence before any repair decision.
professional recommendedSeparate a failed lamp or local connection from fuse, ground, wiring, control, and configuration concerns before replacing parts.
beginnerSeparate a missing lamp or changed circuit load from socket, wiring, switch, module, hazard, and control evidence before replacing a flasher or lamp.
beginnerSeparate blade and glass conditions from fuse, switch, motor, linkage, washer, wiring, module, and frozen-system evidence while protecting visibility and the windshield.
intermediateReduced 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 recommendedDetermine whether the battery is undercharged, unable to store energy, losing energy while parked, or disconnected by a cable fault.
intermediateSeparate an intermittent radio or screen reset from a complete power loss by recording what else resets, then test supply, ground, protection, network, and heat evidence before blaming the head unit.
intermediateThe engine does not rotate when starting. Separate battery, cable, starter-control, interlock, security, and starter faults before replacing anything.
intermediateTreat overheating as a stop-and-assess condition, then separate coolant loss, airflow, circulation, control, and combustion concerns.
professional recommendedSeparate airflow, temperature, humidity, glass, control-door, blower, and cooling-system evidence before driving in conditions where the windshield cannot stay clear.
intermediateUse lamp behavior, symptoms, code status, freeze frame, readiness, and system tests to understand what the vehicle detected without treating a code as a parts order.
beginnerFirst determine whether the engine cannot make power, the transmission is not transferring it, or a chassis/control system is limiting torque.
intermediateClassify smoke or a burning smell by location, color, timing, and nearby systems before attempting another drive or touching a hot component.
intermediateWater inside the cabin after rain, washing, or HVAC use can come from drains, seals, glass, body openings, or condensation. Locate the path before removing trim or blaming a coolant leak.
intermediateRestore a safe rear-visibility workflow by separating a camera, reverse-input, power, ground, connector, display, network, or software concern before replacing a module.
intermediateThe control module detected intermittent, implausible, or high vehicle-speed-signal behavior. The generic code does not prove which sensor, wheel-speed source, wiring path, module, or communication path is responsible.
Generic codeThe generic DTC identifies a purge-control valve circuit condition. It does not prove the purge valve itself is mechanically or electrically failed; wiring, connectors, power/ground, driver control, and exact circuit design must be tested.
Generic codeThe generic DTC identifies an open-circuit condition in the EVAP vent-control circuit. It does not prove the vent valve or solenoid itself is failed.
Generic codeThe generic DTC identifies an open-circuit condition in the purge-control valve circuit. It narrows the electrical fault type, but it still does not prove the purge valve itself is the failed part.
Generic codeThe generic DTC identifies a vent-control circuit malfunction. It does not identify whether the fault is the vent device, wiring, connector, power/ground, control driver, or another exact-vehicle circuit condition.
Generic codeThe generic DTC identifies a short-circuit condition in the purge-control valve circuit. It does not establish whether the short is in the device, harness, connector, supply/control path, or module driver.
Generic codeThe generic DTC identifies a short-circuit condition in the EVAP vent-control circuit. It does not identify the exact location of the short or prove the vent device itself is the cause.
Generic codeThe generic DTC identifies a malfunction in the EVAP vent valve or solenoid control circuit. It is a circuit-level finding, not proof that the vent valve or solenoid should be replaced.
Generic codeThe control module reported a vehicle-speed-signal condition. The standardized code identifies the monitored speed-signal category; it does not prove which sensor, wheel-speed source, wiring path, module, or communication path is responsible.
Generic codeThe control module reported vehicle-speed-signal behavior outside its expected relationship. The standardized code identifies the monitored speed-signal category; it does not prove which sensor, wheel-speed source, wiring path, module, or communication path is responsible.
Generic codeThe control module detected a vehicle-speed-signal input below the range expected by its monitoring strategy. The generic code does not prove which sensor, wheel-speed source, wiring path, module, or communication path is responsible.
Generic codeThe vehicle has detected a charging-system or electrical-generation concern. The battery symbol does not by itself prove the battery failed.
Assess promptlyThe anti-lock braking system has reported a fault or has been disabled. Base braking may behave differently, and the exact effect depends on the vehicle and any other warning lamps.
Assess promptlyThe traction-control, stability-control, or related chassis-control system has reported a fault, has been switched off, or is actively intervening. The lamp alone does not identify a failed sensor or module.
Assess promptlyThe supplemental restraint system has detected a fault or is not fully available. A lamp is not a reason to probe connectors or install a used restraint component.
CautionCheck whether the vehicle is replenishing electrical energy under its intended operating strategy instead of applying one universal voltage rule.
Test-first procedureSeparate state of charge, battery condition, and connection problems before blaming the starter or alternator.
Test-first procedureFind resistance in a loaded power or ground path without assuming that continuity or an unloaded voltage proves the circuit is healthy.
Test-first procedureInvestigate key-off battery drain only after the vehicle has entered its correct sleep state and the evidence is preserved.
Test-first procedureIAR 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.