Go to the bottom of the page to view the trouble code section.
Each section includes likely causes for the problem listed.
Engine:- Engine lopes while idling or idle is erratic
1 - Vacuum leak
2 - EGR valve leaking or plugged PCV valve
3 - Fuel pump not able to maintain required fuel pressure
4 - Leaking head gasket
6 - Timing chain and/or gears worn
7 - Spark plugs worn or not gapped correctly
8 - Ignition timing not correct
9 - Air filter clogged
- Engine starts but stops immediately
1 - Loose or faulty electrical connections at the distributor, coil
or alternator
2 - Insufficient fuel reaching injectors
3 - Vacuum leak (check at gasket between intake manifold and throttle
body)
- Engine difficult to start when cold
1 - Battery not charged or low
2 - Fuel system faulty
3 - Fuel system leaking
4 - Distributor system faulty
- Engine difficult to start when warm
1 - Fuel system faulty
2 - Corroded battery connections
3 - Clogged air filter
- Engine stumbles on acceleration or misses throughout driving range
1 - Spark plugs faulty
2 - Fuel injection system faulty or needs adjustment
3 - Fuel filter clogged
4 - Incorrect ignition timing or faulty ignition system
5 - Faulty emission system
6 - Vacuum leak in intake system or vacuum hoses
7 - Cylinder compression low
- Knocking or pinging sound during acceleration
1 - Incorrect octane fuel used
2 - Ignition timing incorrect
3 - Damaged spark plug wires
4 - Worn or damaged distributor components
- Loud knocking or ticking that matches engine rpm
1 - Rod bearing out of tolerance
2 - Broken or damaged rocker arm
3 - Damaged cam
- Overheating
1 - Insufficient coolant in system
2 - Water pump drive belt defective or water pump faulty
3 - Faulty thermostat
4 - Radiator cap not maintaining proper pressure
5 - Ignition timing not correct
6 - Obstruction clogging cooling system
7 - Coolant fan motor or relay faulty
Clutch:- Clutch starts to engage even when pedal is pressed to the floor
1 - Faulty master or slave cylinder
2 - Broken or damaged clutch components
- Clutch pedal firmly stops before reaching floor and/or clutch won't release
1 - Clutch release arm broken or damaged
- Pedal feels spongy
1 - Air in system
- Unable to select gears when pedal is pressed
1 - Faulty clutch disc and/or pressure plate
2 - Fork and bearing not assembled properly
3 - Faulty transmission
- Clutch slips
1 - Clutch plate worn
2 - Clutch is new and requires normal use to seat the plate properly
3 - Weak diaphragm spring
4 - Rear main seal leaking spilling oil on the clutch plate
- Squealing sound from engine compartment when clutch is slipped
1 - Worn clutch components
General:- Excessive fuel consumption
1 - Clogged air filter
2 - Oxygen sensor faulty
3 - Incorrect ignition timing
4 - Fuel injection system damaged or worn
- Clicking noise during cornering
1 - Worn or damaged outboard CV joint
- Knocking or clicking noise from engine compartment at low speeds, matches
vehicle speed rather than engine rpm
1 - Worn axle CV joints
2 - Worn side gear hub centerbore
- Clunk sound on acceleration or deceleration
1 - Loose, worn or damaged engine mounts
- Noise when transmission is in neutral and engine running with clutch
released
1 - Damaged input gear bearing
2 - Damaged clutch release bearing
- Difficult or almost impossible to shift transmission into gear, especially
first gear or reverse with clutch pedal pressed to the floor
1 - Clutch not releasing or faulty clutch (see clutch symptoms)
2 - Transmission cables out of adjustment
3 - Faulty transmission
- Air appears in cooling system even after being filled correctly. Results
in overheating and problem repeats of cooling system is refilled.
1 - Broken or cracked impeller disc on water pump
2 - Water pump loose
- Quiet hissing sound coupled with fuel smell from engine compartment
1 - Main fuel inlet line at fuel rail not installed properly or loose
- Tires produce smoke when engine is set at 4000 rpm and clutch is released
1 - You own a V-6 Fiero and can't resist
2 - uh, your foot slipped off the clutch pedal
3 - You're getting ready to change your tires
4 - You're winning a bet
5 - Just testing
Trouble Code Diagnosis
If the check engine light comes on, you can identify the cause by
connecting the bottom-left side terminals with a paper clip. Turn
your car off, insert clip into terminals, connecting them electrically.
Turn the ignition on, but do not start the car. Count the number of
blinks the check engine light displays. The first series of blinks
gives you the first digit of the code, the second series is the second
digit (imagine that). Code 12 (one blink, followed by two) will blink
twice and then any stored codes will follow. Below is a diagram showing
which terminals to connect. The diagram is based on the terminal facing
away from the firewall, observed from the front.
