Automotive Troubleshooting

The most inexpensive and easiest way to keep your vehicle operating properly is simply to check it over on a regular basis. This is the best to way spot individual problems before other component problems occur and compound the symptoms. When maintenance is ignored, over a period of time, multiple repairs usually become necessary. This makes diagnosing the symptoms more difficult than if they had been discovered individually during periodic checks.

The emissions, fuel, ignition, and engine management systems are interrelated, a minor problem in one can have a ripple effect on others. These minor malfunctions among several systems can eventually lead to a breakdown which could have been avoided by a simple check and maintenance Procedures.

To start trouble shooting is is best to start with the basics first. Check for any cracks or other damage to hoses, vacuum, fuel and air intakes. Is the belts, battery and fluids in good shape. An engine needs spark, fuel, compression and air. Determine where the problem might be related to these systems. Is the symptoms happens when the vehicle is cold, hot or when it is humid out. Determining the environment when these symptoms occur will often lead you where to look.

Engine will not rotate when attempting to start Engine rotates but will not run
1. Battery terminal connections loose or corroded 1. Fuel tank empty
2. Battery discharged or faulty 2. Battery discharged ( engine rotates slowly )
3. Automatic trans axle not completely engaged in park 3. Battery terminals connections loose or corroded
4. Broken, loose or disconnected wiring in the starting circuit 4. Leaking fuel injectors, fuel pump, pressure regulator etc.
5. Starter motor pinion jammed in flywheel ring gear 5. Fuel not reaching fuel injection system
6. Starter solenoid faulty 6. Ignition components damp or damaged
7. Starter motor faulty 7. Worn, faulty or incorrectly gapped spark plugs
8. Ignition switch faulty 8. Broken, loose or disconnected wiring in the starting circuit
9. Starter pinion or flywheel teeth worn or broken 9. Broken, loose or disconnected wires at the ignition coil or faulty coil
10. Engine seized 10. Broken or stripped timing belt or chain


Engine hard to start when cold Engine hard to start hot
1. Battery discharged or low 1. Air filter clogged
2. Malfunctioning fuel system 2. Fuel not reaching the fuel injection system
3. Fuel injectors leaking 3. Mal functional engine control system
4. Malfunctioning engine control system 4. Corroded battery connections ( ground! )


Starter motor noisy or rough in engagement Engine starts but stops immediately
1. Pinion or flywheel gear teeth worn or broken 1. Loose or faulty electrical connections at distributor, coil or alternator
2. Starter motor mounting bolts loose or missing 2. Insufficient fuel reaching the fuel injectors
3. Vacuum leak at the gasket between the intake plenum\fuel injection throttle body
4. Malfunctioning engine control system


Oil Puddle under Car Engine lobes while idling or idles erratically
1. Oil Pan Gasket and/or oil pan drain bolt washer leaking 1. Vacuum leakage
2. Oil pressure sending unit leaking 2. Leaking EGR valve
3. Valve covers leaking 3. Air filter clogged
4. Engine oil seals leaking 4. Fuel pump not delivering sufficient fuel to the fuel injection system
5. Oil pump housing leaking 5. Leaking head gasket
6. Timing chain/belt and/or sprockets worn
7. Camshaft lobes worn
8. malfunctioning engine control system
Engine misses at idle speed Engine misses throughout driving speed range
1. Spark plug worn or not gapped properly 1. Fuel filter clogged and/or impurities in the fuel system
2. Faulty spark plug wires 2. Low fuel output at the injectors. injector defective
3. Vacuum leaks 3. Faulty or incorrectly gapped spark plugs
4. Uneven or low compression 4. Incorrect ignition timing
5. Defective fuel injector 5. Spark plug wire defective
6. Malfunctioning engine control system 6. Faulty engine control/emission system components
7. Camshaft lobe or valve train component worn 7. Low or uneven cylinder compression pressures
8. Weak or faulty ignition system
9. Vacuum leak at the fuel injector throttle body, intake manifold, or vacuum hoses
10. Camshaft lobe or valve train component worn


Engine Stumbles on acceleration Engine surges while holding accelerator steady
1. Spark plugs fouled 1. Intake air leak
2. Fuel filter clogged 2. Malfunctioning Torque Converter Clutch/solenoid
3. Malfunctioning fuel supply or fuel injection system 3. Malfunctioning fuel supply or fuel injection system
4. Malfunctioning engine control system 4. Malfunctioning engine control system
5. EVAP system leaking or malfunctioning 5. Contaminated or defective oxygen sensors
6. Alternator output low or excessive 6. Malfunctioning EGR system
Engine stalls Engine lacks power
1. Accelerator cable linkage binding or sticking 1. Incorrect ignition system
2. Idle air control system malfunctioning system 2. Faulty or incorrectly gapped spark plugs
3. Fuel filter clogged and/or water and impurities in the fuel system 3. Faulty ignition coil
4. Malfunctioning fuel supply or fuel injection system 4. Rear brakes binding
5. Malfunctioning engine control system 5. Automatic transmission fluid level
6. Malfunctioning EGR system 6. Malfunctioning fuel supply or fuel injection system
7. Malfunctioning engine control system
8. Low cylinder compression
9. Restriction in the catalytic converter or exhaust system
Engine Backfires Pinging or knocking engine sounds
1. Emission control system not functioning properly 1. Incorrect grade of fuel
2. Ignition timing incorrect 2. Fuel injection system faulty
3. Faulty secondary ignition system; cracked spark plug insulator, faulty plug wires 3. Improper or damaged spark plugs
4. Fuel injection system malfunction 4. Faulty or incorrect thermostat
5. Vacuum leak at fuel injectors, intake manifold or vacuum hoses 5. low coolant levels
6. EGR stuck open all the time 6. Knock sensor system faulty
7. Malfunctioning control system 7. Vacuum leak
8. EGR system not functioning properly
9. Malfunctioning engine control system
Engine runs with oil pressure light on Engine diesels after switching off
1. Low oil level 1. Excessive engine operating temperature
2. Short in wiring circuit 2. Idle speed to high
3. Faulty oil pressure sender
4. Worn engine bearings and/or oil pump

Engine Electrical System Troubleshooting

Battery will hold a charge Alternator light fails to go out
1. Alternator drive belt defective or not tightened properly 1. Faulty alternator or charging circuit
2. Battery electrolyte level low 2. Alternator discreet defective or out of adjustment
3. Battery terminals loose or corroded 3. Alternator voltage regulator inoperative
4. Alternator not charging properly
5. Loose, broken or faulty wiring in the charging circuit
6. Short in vehicle wiring
7. Internally defective battery
Alternator light fails to come on when key is turned on
1. Warning light bulb defective
2. Fault in the printed circuit, dash wiring or bulb holder


Horn do not work Horn is weak
1. Bad Fuse 1. Faulty Ground at horn
2. Loose, broken or faulty wiring in the horn circuit 2. Loose, broken or faulty wiring in the horn circuit
3. Faulty horn relay 3. Weak power supply “check voltage”
4. Faulty horn button 4. One or two horns defective
5. Faulty horns “check with jumper wires” 5. Horn needs adjustment
Horn won’t shut off
1.Check for short circuit to ground
2.Check for defective components – horn button, relay, horn

Power Door Locks

None of the power locks operate

One power lock does not operate, but others
1.Check for bad fuse 1. Loose, broken or faulty wiring
2.Check for bad relay 2. Switch faulty
3. Check lock master switch 3. Lock Solenoid faulty
4. Loose, broken or faulty wiring

on Power Locks

Power Windows

No Windows Operate
One Window does not Operate
1. Check the fuse 1. Loose, broken or faulty wiring
2. Check power window relay 2. Check power window relay
3. Check master lock out switch 3. Check window switch
4. Loose, broken or faulty wiring 4. Check window reguator and motor
5. Check switch controls 5. Check window channels for binding

on Power windows

Fuel System

Excessive fuel consumption Fuel leakage and/or fuel odor
1. Dirty or clogged air filter element 1. Leaking fuel feed or return line
2. Restriction in the catalytic converter or exhaust system 2. Tank overfilled
3. Emissions or engine control system not functioning properly 3. Evaporative canister filter clogged
4. Fuel injection system malfunction 4. Fuel injection system malfunction
5. Low tire pressure or incorrect tire size

Cooling System

Overheating Overcooling
1. In sufficient coolant in system 1. Faulty thermostat
2. Water pump drive belt defective or out of adjustment 2. Inaccurate temperature gauge sending unit
3. Radiator core blocked or grille restricted
4. Thermostat faulty
5. Electric radiator fan inoperative or blades broken or cracked
6. Radiator cap not maintaining proper pressure

cooling trouble chart

Coolant loss Poor coolant circulation
1. Too much coolant in system 1. Inoperative water pump
2. Coolant boiling away because of over heating 2. Restriction cooling system
3. Internal or external leakage 3. Water pump drive belt defective
4. Faulty radiator cap 4. Thermostat sticking
External coolant leakage Internal coolant leakage
1. Deteriorated/damaged hoses; loose clamps 1. Leaking cylinder head gasket
2. Water pump seal defective 2. Cracked cylinder bore or cylinder head
3. Leakage from radiator core or coolant reservoir bottle
4. Engine drain or water jacket core plugs leaking


Vehicle pulls to one side during braking Excessive brake pedal effort required to stop vehicle
1. Incorrect tire pressures 1. Malfunctioning power brake booster
2. Front end out of line 2. Partial system failure
3. Front or rear tires not matched to one another 3. Excessively worn pads or shoes
4. Restricted brake lines 4. Piston in caliper or wheel cylinder stuck or sluggish
5. Malfunctioning brake caliper or drum brake assembly 5. Brake pads or shoes contaminated with oil or grease
6. Loose suspension parts 6. New pads or shoes installed and not yet seated. It will take a while for the new material to seat against the disk or drum.
7. Loose calipers
8. Excessive wear brake shoe or pad material or disk/drum on one side
Noise (high-pitch squeal when the brakes are applied) Brake roughness or chatter (pedal pulsates)
1. Front disk pads worn out. The noise comes from the wear senor rubbing against the disc (does not apply to all vehicles) 1. Excessive lateral run out of brake disc
2. Incorrectly installed new pads ( many require an anti squeal compound on the backing plates) 2. Rear brake drum out-of-round
3. Uneven pad wear
4. Defective disc
Dragging brakes Grabbing or uneven braking action
1. Incorrect adjustment of brake light switch 1. Malfunctioning of proportioning valve
2. Master cylinder pistons not returning correctly 2. Malfunctioning of power brake booster unit
3. Restricted brake lines or hoses 3. Binding brake pedal mechanism
4. Incorrect parking brake adjustment 4. Brake fluid, grease or oil on brake pads or shoes
5. Caliper piston sticking
Excessive brake pedal travel Brake pedal feels spongy when depressed
1. Partial brake system failure 1. Air in hydraulic lines
2. Insufficient fluid in master cylinder 2. Master cylinder mounting bolts loose
3. Air trapped in system 3. Master cylinder defective
Brake pedal travels to floor with little resistance Parking brake does not hold
1. Little or no fluid in the master cylinder reservoir caused by leaking caliper or wheel cylinder pistons 1. Parking brake linkage improperly adjusted
2. Loose, damaged or disconnected brake lines

Suspension and Steering System

Vehicle pulls to one side Abnormal or excessive tire wear
1. Mismatched or uneven tire 1. Wheel alignment
2. Broken or sagging springs 2. Sagging or broken springs
3. Wheels in need of alignment 3. Tire out of balance
4. Front brake dragging 4. Worn strut damper
5. Overloaded vehicle
6. Tires not rotated regularly
7. Tire pressure not correct
Shimmy, shake or vibration Wheel makes a thumping noise
1. Tire or wheel out of balance or out of round 1. Blister or bump on tire
2. Loose or worn wheel bearings 2. Improper strut damper action
3. Worn tie-rod ends
4. Worn lower ball joints
5. Excessive wheel run out
6. Blister or bump on tire
7. Steering gear mounting bolts loose
Hard Steering Poor returnability of steering to center
1. Lack of lubrication at ball joints, tie-rod ends and steering gear 1. Lack of lubrication at ball joints and tie-rod ends
2. Front wheel alignment 2. Binding in ball joints
3. Low tire pressure 3. Binding in steering column
4. Power steering fluid low 4. Lack of lubricant in steering gear assembly
5. Power steering pump or steering gear defective 5. Front wheels in need of alignment or front suspension components bent
Abnormal noise at the front end Wander or poor steering stability
1. Lack of lubrication at ball joints and tie rod ends 1. Mismatched or uneven tires
2. Damaged strut mountings 2. Lack of lubrication at ball joints and tie rod ends
3. Worn control arm bushings or tie rod ends 3. Worn strut assemblies
4. Loose stabilizer bar 4. Loose stabilizer bar
5. Loose wheel nuts 5. Broken or sagging springs
6. Loose suspension bolts 6. Wheel alignment
Excessive pitching and/or rolling around corners or during braking Suspension Bottoms
1. Loose stabilizer bar 1. Overloaded vehicle
2. Worn Strut dampers or mountings 2. Worn strut dampers
3. Broken or sagging springs 3. Incorrect, broken or sagging springs
4. Overloaded vehicle
Cupped tires Excessive tire wear on outside edge
1. Front wheel or rear wheel alignment 1. Inflation pressures incorrect
2. Worn strut dampers 2. Excessive speed in turns
3. Wheel bearings worn 3. Front end alignment incorrect
4. Excessive tire or wheel run out 4. Suspension arm bent or twisted
5. Worn ball joints
Excessive tire wear on inside edge Tire tread worn in one place
1. Inflation pressures incorrect 1. Tires out of balance
2. Front end alignment incorrect 2. Damaged or buckled wheel
3. Loose or damaged steering components 3. Defective tire
Excessive play or looseness in steering system Rattling or clicking noise in steering gear
1. Wheel bearings worn 1. Insufficient or improper lubricant in steering gear assembly
2. Tie rod ends loose 2. Steering gear attachment loose
3. Steering gear loose
4. Worn or loose steering intermediate shaft