15 Common Car Problems & How to Diagnose Them (Step-by-Step)
Skanyx Team••15 min read
Learn the 15 most common car problems, their symptoms, how to diagnose each with SKANYX, DIY vs mechanic options, and cost estimates. Complete guide.
15 Common Car Problems & How to Diagnose Them (Step-by-Step)
Your car is acting strange. What's wrong? This guide covers the 15 most common car problems, how to diagnose them, and whether to DIY or visit a mechanic.
1. Check Engine Light On
Symptoms:- Orange/yellow light on dashboard
- May be solid or flashing
- Car may run normally or have issues
- Connect SKANYX to OBD2 port
- Run diagnostic scan
- Read codes (P0300, P0420, etc.)
- AI analyzes root cause
- Get cost estimates and repair guidance
- Loose gas cap (€10-20 fix)
- Oxygen sensor (€150-300)
- Catalytic converter (€800-2,500)
- Spark plugs (€200-500)
- Gas cap: DIY (easy)
- Oxygen sensor: DIY (moderate)
- Catalytic converter: Mechanic (difficult)
- Spark plugs: DIY (moderate)
- Diagnosis: €39 (SKANYX) vs €150 (mechanic)
- Repairs: €20-2,500 (depends on problem)
- Use SKANYX to identify exact problem
- Follow AI-powered repair guidance
- Clear codes after repair
2. Engine Misfire
Symptoms:- Rough idle
- Loss of power
- Engine shaking
- Check engine light (P0300 code)
- Scan with SKANYX
- Check for P0300 (random misfire) or P0301-P0308 (cylinder-specific)
- AI identifies which cylinder is misfiring
- Live data shows misfire counts
- Get repair recommendations
- Worn spark plugs (€50-150)
- Failed ignition coil (€100-200)
- Bad spark plug wires (€50-100)
- Fuel injector problems (€200-400)
- Spark plugs: DIY (moderate skill)
- Ignition coil: DIY (moderate skill)
- Fuel injector: Mechanic (advanced)
- Diagnosis: €39 (SKANYX)
- Repairs: €50-400 (depends on cause)
- Replace spark plugs/coils
- Clear codes
- Verify misfire resolved
3. Battery Problems
Symptoms:- Car won't start
- Battery light on
- Dim headlights
- Slow engine crank
- Check battery voltage (should be 12.6V)
- Use SKANYX to monitor voltage patterns
- AI predicts battery failure weeks early
- Check charging system
- Get replacement recommendations
- Dead battery (€100-200)
- Alternator failure (€300-800)
- Bad connections (€20-50)
- Parasitic drain (€50-150)
- Battery replacement: DIY (easy)
- Alternator: DIY (moderate) or mechanic
- Connections: DIY (easy)
- Diagnosis: €39 (SKANYX)
- Battery: €100-200
- Alternator: €300-800
- Replace battery if voltage low
- Test alternator charging
- Clean connections
- Use SKANYX to monitor battery health
4. Transmission Problems
Symptoms:- Slipping gears
- Delayed shifting
- Grinding noises
- Transmission warning light
- Burning smell
- Scan with SKANYX
- Check transmission codes
- Monitor shift quality data
- AI analyzes transmission health
- Get cost estimates
- Low transmission fluid (€50-100)
- Worn clutch (manual) (€500-1,500)
- Transmission failure (€1,500-5,000)
- Solenoid problems (€300-800)
- Fluid check/change: DIY (easy)
- Solenoid: Mechanic (moderate)
- Clutch/transmission: Mechanic (advanced)
- Diagnosis: €39 (SKANYX)
- Fluid service: €100-200
- Solenoid: €300-800
- Transmission rebuild: €1,500-5,000
- Check fluid level first
- Address problems early (prevents expensive repairs)
- Use SKANYX to monitor transmission health
5. Brake Problems
Symptoms:- Squeaking/squealing
- Grinding noise
- Soft brake pedal
- Brake warning light
- Car pulls to one side
- Visual inspection (brake pads, rotors)
- Check brake fluid level
- Scan with SKANYX for ABS codes
- Test brake performance
- Get repair recommendations
- Worn brake pads (€100-300)
- Worn rotors (€200-500)
- Low brake fluid (€20-50)
- ABS sensor failure (€150-300)
- Brake pads: DIY (moderate skill)
- Rotors: DIY (moderate skill)
- ABS sensor: Mechanic (moderate)
- Diagnosis: €39 (SKANYX)
- Brake pads: €100-300
- Rotors: €200-500
- Full brake job: €300-800
- Replace brake pads before metal-on-metal
- Resurface or replace rotors
- Address ABS issues promptly
6. Overheating
Symptoms:- Temperature gauge in red
- Steam from engine
- Coolant smell
- Engine warning light
- Check coolant level
- Scan with SKANYX for temperature codes
- Monitor coolant temperature data
- Check for leaks
- Test thermostat
- Low coolant (€20-50)
- Thermostat stuck (€100-200)
- Water pump failure (€300-600)
- Radiator leak (€300-800)
- Head gasket failure (€1,000-2,500)
- Coolant top-up: DIY (easy)
- Thermostat: DIY (moderate)
- Water pump: Mechanic (moderate)
- Head gasket: Mechanic (advanced)
- Diagnosis: €39 (SKANYX)
- Coolant: €20-50
- Thermostat: €100-200
- Water pump: €300-600
- Head gasket: €1,000-2,500
- Never drive with overheating
- Check coolant regularly
- Address leaks immediately
- Use SKANYX to monitor temperature
7. Electrical Problems
Symptoms:- Lights flickering
- Dead battery
- Fuses blowing
- Electrical components not working
- Warning lights
- Check battery voltage
- Scan with SKANYX for electrical codes
- Test alternator output
- Check fuses
- Inspect wiring
- Bad alternator (€300-800)
- Faulty battery (€100-200)
- Bad ground connection (€50-150)
- Short circuit (€100-300)
- Fuse problems (€10-50)
- Fuses: DIY (easy)
- Battery: DIY (easy)
- Alternator: DIY (moderate) or mechanic
- Wiring: Mechanic (advanced)
- Diagnosis: €39 (SKANYX)
- Battery: €100-200
- Alternator: €300-800
- Wiring repair: €100-500
- Replace faulty components
- Fix wiring issues
- Use SKANYX to monitor electrical system
8. Air Conditioning Not Working
Symptoms:- No cold air
- Weak airflow
- Strange noises
- AC light flashing
- Check AC refrigerant level
- Scan with SKANYX for AC codes
- Test AC compressor
- Check for leaks
- Get repair estimates
- Low refrigerant (€100-200)
- AC compressor failure (€500-1,500)
- Leak in system (€200-500)
- Blower motor failure (€200-400)
- Refrigerant recharge: Mechanic (requires equipment)
- Compressor: Mechanic (advanced)
- Blower motor: DIY (moderate)
- Diagnosis: €39 (SKANYX)
- Refrigerant: €100-200
- Compressor: €500-1,500
- Full AC repair: €300-1,500
- Recharge refrigerant if low
- Replace compressor if failed
- Fix leaks
- Use SKANYX to monitor AC system
9. Rough Idle
Symptoms:- Engine shakes at idle
- RPM fluctuates
- Stalling
- Check engine light
- Scan with SKANYX
- Check for misfire codes
- Monitor idle RPM data
- Check fuel trim values
- AI identifies root cause
- Dirty throttle body (€50-150)
- Vacuum leak (€100-300)
- Bad idle air control valve (€150-300)
- Spark plug problems (€200-500)
- Throttle body cleaning: DIY (moderate)
- Vacuum leak: DIY (moderate)
- IAC valve: DIY (moderate)
- Diagnosis: €39 (SKANYX)
- Throttle cleaning: €50-150
- Vacuum leak: €100-300
- IAC valve: €150-300
- Clean throttle body
- Fix vacuum leaks
- Replace IAC valve if needed
- Use SKANYX to monitor idle quality
10. Poor Fuel Economy
Symptoms:- Lower MPG than normal
- More frequent fill-ups
- No other symptoms
- Track fuel consumption
- Scan with SKANYX
- Check oxygen sensor data
- Monitor fuel trim values
- AI identifies efficiency problems
- Dirty air filter (€20-50)
- Bad oxygen sensor (€150-300)
- Tire pressure low (€0-20)
- Spark plugs worn (€200-500)
- Fuel system problems (€200-600)
- Air filter: DIY (easy)
- Oxygen sensor: DIY (moderate)
- Tire pressure: DIY (easy)
- Spark plugs: DIY (moderate)
- Diagnosis: €39 (SKANYX)
- Air filter: €20-50
- Oxygen sensor: €150-300
- Spark plugs: €200-500
- Replace air filter regularly
- Fix oxygen sensor issues
- Maintain proper tire pressure
- Use SKANYX to monitor fuel efficiency
11. Exhaust Smoke
Symptoms:- White smoke from exhaust
- Blue smoke from exhaust
- Black smoke from exhaust
- Burning smell
- Identify smoke color
- Scan with SKANYX for engine codes
- Check oil consumption
- Monitor engine data
- Get diagnosis
- White smoke: Coolant leak (€1,000-2,500)
- Blue smoke: Oil burning (€500-2,000)
- Black smoke: Rich fuel mixture (€200-600)
- All exhaust smoke issues: Mechanic (advanced)
- Diagnosis: €39 (SKANYX)
- Coolant leak repair: €1,000-2,500
- Oil leak repair: €500-2,000
- Fuel system: €200-600
- Address immediately (can indicate serious problems)
- Use SKANYX to identify root cause
- Get professional repair if needed
12. Steering Problems
Symptoms:- Hard to steer
- Steering wheel shakes
- Pulling to one side
- Power steering fluid leak
- Check power steering fluid
- Inspect for leaks
- Test steering components
- Scan with SKANYX for related codes
- Get repair recommendations
- Low power steering fluid (€20-50)
- Power steering pump failure (€300-600)
- Steering rack problems (€500-1,500)
- Alignment issues (€50-150)
- Fluid top-up: DIY (easy)
- Pump: Mechanic (moderate)
- Steering rack: Mechanic (advanced)
- Alignment: Mechanic (requires equipment)
- Diagnosis: €39 (SKANYX)
- Fluid: €20-50
- Pump: €300-600
- Steering rack: €500-1,500
- Alignment: €50-150
- Top up fluid if low
- Replace pump if failed
- Fix leaks promptly
- Get alignment if pulling
13. Suspension Problems
Symptoms:- Bumpy ride
- Car bounces excessively
- Uneven tire wear
- Clunking noises
- Car sits lower
- Visual inspection (shocks, struts)
- Test ride quality
- Check tire wear patterns
- Scan with SKANYX for related codes
- Get repair estimates
- Worn shocks/struts (€300-800)
- Broken springs (€200-600)
- Worn bushings (€200-500)
- Alignment problems (€50-150)
- Shocks/struts: Mechanic (moderate)
- Springs: Mechanic (moderate)
- Bushings: Mechanic (moderate)
- Diagnosis: €39 (SKANYX)
- Shocks/struts: €300-800
- Springs: €200-600
- Full suspension: €500-1,500
- Replace worn components
- Get alignment after suspension work
- Use SKANYX to monitor suspension health
14. Starter Problems
Symptoms:- Car won't start
- Clicking sound when turning key
- No sound at all
- Intermittent starting
- Check battery voltage
- Test starter motor
- Check starter relay
- Inspect connections
- Get repair recommendations
- Dead battery (€100-200)
- Bad starter motor (€300-600)
- Faulty starter relay (€50-150)
- Bad connections (€50-100)
- Battery: DIY (easy)
- Starter relay: DIY (moderate)
- Starter motor: Mechanic (moderate)
- Diagnosis: €39 (SKANYX)
- Battery: €100-200
- Starter motor: €300-600
- Relay: €50-150
- Replace battery if dead
- Replace starter if failed
- Fix connections
- Use SKANYX to diagnose electrical issues
15. Catalytic Converter Problems
Symptoms:- Check engine light (P0420 code)
- Reduced power
- Rotten egg smell
- Failed emissions test
- Scan with SKANYX
- Check for P0420 code
- Monitor converter efficiency data
- AI analyzes converter health
- Get cost estimates
- Failed oxygen sensors (most common cause)
- Engine misfires (damaged converter)
- Age/wear (150,000+ miles)
- Contamination
- Oxygen sensors: DIY (moderate)
- Converter replacement: Mechanic (advanced)
- Diagnosis: €39 (SKANYX)
- Oxygen sensors: €150-300
- Catalytic converter: €800-2,500
- Fix underlying cause first (O2 sensors, misfires)
- Replace converter if failed
- Use SKANYX to monitor converter health
- Prevention: Fix problems early to avoid converter damage
How to Diagnose Any Car Problem
Step 1: Identify Symptoms
What to Note:- What's happening? (won't start, rough idle, etc.)
- When does it happen? (cold start, driving, etc.)
- Any warning lights?
- Any strange noises or smells?
Step 2: Use SKANYX to Scan
What SKANYX Does:- Scans all vehicle modules
- Reads diagnostic codes
- Analyzes live data
- AI identifies root causes
- Provides cost estimates
Step 3: Get AI-Powered Diagnosis
SKANYX Analysis:- Identifies exact problem
- Explains in plain English
- Provides repair cost estimates
- Step-by-step repair guidance
- DIY vs. mechanic recommendations
Step 4: Decide DIY vs. Mechanic
DIY If:- Problem is simple (spark plugs, air filter)
- You have tools and skills
- Cost savings justify effort
- Problem is complex (transmission, head gasket)
- Requires special tools
- Safety-critical (brakes, steering)
Step 5: Fix and Verify
After Repair:- Clear codes with SKANYX
- Verify problem resolved
- Monitor for recurrence
- Use SKANYX for regular maintenance
Prevention: Avoid Common Problems
Regular Maintenance
What to Do:- Regular oil changes
- Replace air filter
- Check tire pressure
- Maintain fluid levels
- Use SKANYX for monthly scans
Early Detection
SKANYX Benefits:- Catches problems before they become expensive
- AI predicts failures weeks early
- Saves money with proactive maintenance
- Peace of mind
Cost Savings
Example:- Fix oxygen sensor early: €150
- Wait until converter fails: €2,000
- Savings: €1,850
The Bottom Line
15 Most Common Problems:- Check engine light
- Engine misfire
- Battery problems
- Transmission issues
- Brake problems
- Overheating
- Electrical issues
- AC not working
- Rough idle
- Poor fuel economy
- Exhaust smoke
- Steering problems
- Suspension issues
- Starter problems
- Catalytic converter
- Use SKANYX for instant AI-powered diagnosis
- Get cost estimates and repair guidance
- Decide DIY vs. mechanic
- Fix problems early to save money
- Regular SKANYX scans catch problems early
- AI predicts failures before they happen
- Comprehensive guidance helps you fix issues
- Saves money compared to mechanic visits
Diagnose Your Car Problems Now
Don't guess what's wrong. Get instant AI-powered diagnosis with SKANYX.
Why SKANYX:- Diagnose any problem in 30 seconds
- AI-powered analysis
- Cost estimates
- Repair guidance
- Cheaper than one mechanic visit (€39 vs €150)
Want to learn more? Check out SKANYX features or see our pricing to get started.
Stop guessing. Start diagnosing. Get SKANYX today.Skanyx Team
Automotive Diagnostics Experts
The Skanyx Team combines years of automotive expertise with cutting-edge AI technology to help car owners understand and maintain their vehicles better.