hi i am new to this forum. and recently i am renting several Honda accords. i owned an 88 for 14 years and i think it is the best car i ever owned. the car i am asking about is a 93 accord sedan lx auto with 95k miles and the check engine light comes on after a few minuets of driving. the code is 12 which as i understand it is the ERG. one of my mechanics says i should replace the erg. NAPA has them for about $170 and ebay for $100, and he wants $180 to do the work. another mechanic is saying to clean it and will do for $25. my 1st question is since the car is running fine do i need to do anything? and second if i do need to do something what would be best. i have read several posts that say if the posts are clogged that that wont affect the check engine light. and is it such a big job to change that is would cost $180?
thanks, dj

 

93 Accords have a lift sensor on the EGR valve. ECU will expect the lift sensor to register a certain amount of lift for a given RPM. If the ECU is not seeing the expected lift sensor electrical output there may be a few things wrong.

Check that the electrical connector and wires to the EGR valve are not damaged or corroded.

Check that there is vacuum going to the EGR valve to activate it. If the vacuum hose is damaged, missing, or incorrectly hooked up, the EGR valve will not open.

If there is vacuum and the electrical connections are fine, there may be soot preventing the valve from opening, or fully opening. Or if the diaphragm inside the EGR valve is damage and does not hold vacuum or the sensor is damaged, then the valve will need to be replaced.

 

thanks so much that is a big help.
can i keep driving until i can get a mechanic here to help?

are the erg electric connectors and vacuum line easy to access or to i need to do through the process of removal?

am i right that if there soot preventing the valve from fully opening i need to replace the erg? no way to try to clean it?

by the way i am living in HI, island of Maui. HI has no emission requirements.

thanks again, dj

 

You can keep driving it, I don't think the ECU goes into limp mode with the EGR lift circuit has a fault.
The EGR valve sits on the intake manifold. It will have an electrical connector on top and a vacuum hose at an angle near the top.

If could be a build up of soot, the valve could be sticking and needs to be manually exercised, there is no vacuum on the line going to the diaphragm, the diaphragm is damaged, or the electrical component of the valve or the wire to the valve is damaged.

The valve will only need to be replaced if the valve itself is damaged, either because of a leaking diaphragm, or faulty electrical sensor.

Although HI may not have emissions testing, a malfunctioning EGR system will cause the car to stumble/buck/misfire at cruise/part throttle. This will affect power and economy.

 

thanks again, that is a big help. i have a back yard mechanic who works on hondas to help, so i will have him help me go through all this.
i also have a 91 accord sedan with same thing, code 12 but that one also has idle that goes up and down. do you think the idle problem would be related to the erg?

 

egr valves are built to last. They normally just need to be cleaned out to allow the plunger to move freely. It's possible the plunger is stuck with soot and just needs to be cleaned. If he wants to clean it for $25, let him do it. That could fix the issue.

However, if the egr valve is really that gunked up it's probable that the egr ports are also gunked up. You might want to have him clean out the valve and the ports. It would take about an hour and a half or maybe two hours depending on his experience so you might want to think about having it done.

Even though cleaning the valve could fix the check engine code from coming on, if the ports are clogged up it could cause your car to fail your next emissions test.

 

EGR only activates at part throttle. Never at idle or W.O.T. By raising the idle a bit, if the vacuum is functional on the EGR valve, you should see the EGR valve begin to open slightly.

Hunting idle is common, go to the top of the page, in the Accord FAQ there is a write up on how to adjust and clean the FITV and IACV.

 

Thank you is all I can say. Now I have some info to work with a mechanic with if they will use it. I have a few and they all have their own opinion. Nice to have facts.