OBD Diagnostic Codes

== All OBD II equipped vehicles (1996 and newer Mustangs included) have the data link connector, or DLC, located underneath the dashboard, just to the right of the steering wheel. Sit in the car and it's most likely above your right knee.

First check the 50 amp fuses in the underhood fuse block.another common thing that can cause that code is one or both of the air diverter valves(check valves)that are vaccumcontrolled by the bypass valve solenoid.these two valves get stuck and do not allow the air from the pump(smog pump)to enter the exhaust.the valves are slver,and have small tubes running into the exhaust manifolds.they have 1 vaccum hose on them. One is above the belt,near the firewall,the other is near the dr. Side of the front valve cover.use a vaccum pump to see if the valves hold vaccum after making sure the solenoid is supplying vaccum when the air pump(smog pump)turns on.another common thing that can cause that code is the air pump(smog pump). The air pump forces pressurized fresh air into the pipes/hoses and past the check valves into the exhaust manifold,accelerating catalyst operation.the spinning vanes of the air pump(smog pump)force air into the diverter valve.during accelaration air is forced through the diverter valve,the check valve,the air injection manifold,and into the exhaust stream.during deceleration the diverter valve blocks air flow,preventing a backfire that could damage the exhaust system.when needed,the diverter valve will release excess pressure to the air cleaner.the code p0410 is the secondary air injection system.the secondary air injection system reduces exhaust emissions following initial engine start up.the components of this system are the air pump(smog pump),the diverter valve,the air ditribution manifold; both known as exhaust manifold and exhaust headers,and the air check valve.the air injection system is designed to introduce clean air to the engine exhaust as it exits the exhaust manifold or exhaust headers.exhaust gases are at their hottest as they leave the combustion chambers. Introducing oxygen to the exhaust at this point allows continued burning of the fuel mixture as it travels down the exhaust system and ultimately out of the tailpipe.

P1506 - Idle Air Control System At Adaptive ClipCheck for vacuum leaks and clean the throttle body, maybe check the iat and maf sensors.

Trouble code P0353 means:Ignition coil C primary/secondary circuit malfunction

The OBD plug is under the dash on the driver side.

o2 sensor

Use the Erase Button on your cheap hand-held OBD II Code Reader. Then drive the vehicle until it does or doesn't come back on. Cross your fingers, hope for the best.

Plug the unit into the obd port on the vehicle and start the read process, when it finishes it will display the active codes and ask you if you would like to clear them.

- Flexible Fuel (FF) sensor to Vehicle Power (VPWR) circuit harness open or shorted

- FF to VPWR circuit poor electrical connection

- Open in FF sensor signal circuit

- Short to ground in FF sensor signal circuit

- Fuel contamination

Thermostat malfunction.

Check the scan head lock. It can easily be locked or unlocked. It is used to protect the moving parts inside the machine when it is moved/transported. Someone in our office was just making copies and ttapping their fingers on it and they locked it without even realizing.

Trouble code P0305 means:Cylinder 5 misfire detected

P0562, charging system voltage low.

The 2004 Ford Focus OBD 2 port is on lower left of hood release; behind unmarked pull-down door

P0300 Diagnostic Code - Random Misfire

Symptoms.
Engine may stumble or miss
Engine may be hard to start
you may notice no issues

Cause
Failing spark plugs or spark plug wires
Bad coil or coil pack
Failing oxygen sensor(s)
Bad fuel injector or more than one
Stuck exhaust valve
Bad catalytic converter
EGR valve or valve passage clogging
Bad camshaft position sensor
Bad PCM or ECM

The Fix
Best first action is a tune up, new plugs, wires, inspect all hoses and wire connections then reset the code. If it returns you will need to narrow it down to a system, coils and coil packs should be tested, catalytic converters for function ( do you smell rotten eggs?). A misfire that jumps cylinders could indicate a lean condition, do you have any other codes along with the 300? this will help clue you in to the source, check valve function to make sure they are opening and closing fully.
This is probably pone of the most difficult codes to troubleshoot, so start with the basics and work your way into the more expensive options, in many cases a good old tune up solves the problem, back it up with a fuel system cleaning and see where you stand.

Random/multiple misfire

I would recommend that you get a shop manual for this vehicle. It will tell you how to find the fault codes and what they mean.

It should be on the driver's side inside the car. Look along the dash below the steering wheel. might be back a little bit, just look along the plastic down there. if you still can't find it, take the car to an autoparts place such as O'Reilly's, Autozone, Advance, etc. The employees there should be able to show you.

The OBD plug is under the dash on the driver side.

Most of the ones the typical DIYer will own will walk you through the process. When you get into more sophisticated ones, then vendor-supplied training becomes a requirement.

missfire on star up first 1000 rpm ignition coil is going bad use a ford coil if you dont want a lot of problems with aftermarket units

Clean your cell with acid if it still gives the code its a bad cell

OBD II is located under drivers side of dash.

Trouble code P0752 means:Shift solenoid A stuck on

Trouble code P0662 means: Intake manifold tuning valve control circuit high (bank 1)