Hey guys,

Just recently joined the Mazda club with a used 2000 Protege. I knew when I was buying it that there were some codes, but I got it at a good price so I figured it would be good once fixed.

These are the codes it's throwing:

P0102 - Mass Air Flow (MAF) Circuit Low Input
P0113 - Intake Air Temperature Circuit High Input
P0118 - Engine Coolant Temperature Circuit High Input
And the famous...
P0402 - Exhaust Gas Recirculation Flow (EGR) Excessive Detected

My main question, is it possible that the EGR is throwing the other codes? The car currently doesn't pass Aircare due to the codes. I haven't had a chance yet to take the EGR Valve off and clean it out.

Thanks!

 

Could be. I'd suggest cleaning the egr, probably have to replace the sensor.

 

Would that be an EGR-related sensor? Or do you mean the MAF/IAT/CT sensors?

Thanks for your reply!

 

Unicorn: Those codes are not as specific as you think. I would start with cleaning out the EGR valve, replace all vacuum hoses, because they are cheap form the reel, make sure the nipple for the EGR boost sensor is not clogged, make sure the EGR ports are open, clean the throttle body inside and out, check the Air intake hose for cracks, clean the MAF sensor and the Air intake sensor, and run a tank with techron fuel system cleaner. Reset the computer by disconnecting the battery negative and stepping on the brake for a few seconds in order to drain any voltage from memories.
If after all that a codes come back we can be more confident that it points to the actual problem.
I would also have a good look at the spark plugs, wires and coil pack.

 

I will give all of that a shot when I get some free time! Thanks!!

 

The air intake code is what is amiss in my mind in relationship to the others

 

So I pulled some stats via Torque for android and my handy bluetooth ODB. These were taken after a 10-15 min. drive and the car had warmed up, but while parked and idling

Air intake - 2.0-2.3 Gal/s
Coolant temp started at 96C idle and went to 103C
Intake air temp started at 26C idle and went to 32C
Rpm idle ~720 average

I'm going to do a driving test on the weekend to see if the Coolant temp will regulate itself. I've already ordered a new Coolant Temp Sensor, and New MAF/IAT sensor.

 

Alright so I got the new MAF + coolant temperature sensor installed, and I cleaned out the EGR valve and lubed it up.

So far no codes have shown up, but I'm still waiting for 2 monitors to turn to ready/complete:

Evaporative System
EGR System

I've done a bunch of driving, and they were Ready/Complete before the reset.

Do they need a cold engine before they can run properly? Any tips to get them to change?

 

The EGR system check occurs when certain conditions are met. The engine needs to be warm and there must be a good vacuum in the intake plenum. And the computer needs to know that these conditions are met. There is a EGR boost sensor circuit. It gets a vacuum signal from the intake manifold. So look for the EGR boost sensor (firewall passenger side in my '98 Protege) and follow the vacuum hose down to the back side of the intake manifold. Pull the hose off and poke with a 2-3" long wire in there. If you feel resitance push through. I would replace this hose because it is probably to stiff to make a good seal anyway.
You get a good vacuum when you drive along at 3k rpm in top gear and then get off the accelerator.

I really don't know much about the evap system other than it uses a carbon canister to catch gasoline fumes and will release these hydrocarbons when appropriate. The fuel system (tank to injector) needs to be tight. The tank lid is most often to blame if it is not tight.

 

For the most part your problem is probably due to a dirty maf. Possibly bad also. Try cleaning it. The egr is probably due to carbon buildup not only right at the egr but also the passages. Coolant temp sensor should just b replaced u will probably find buildup on the sensor when u pull it out.