Hey guys i finally got the codes that i went thru hell getting them but on 27 it says its about the egr but i did replace both the egr n and the egr vacuum solenoid i didn't mind buying the parts bc they never been changed b4. But the other code maf sensor the mechanic tested it n said it was bad,but does a bad maf set code 27 guys?thank u

 

DTC 27 = Exhaust Gas Recirculation (EGR) vacuum control signal solenoid valve circuit.

That diagnostic is based only on the PCM looking at the electrical circuit for the EGR vacuum solenoid, and not seeing the correct voltage. When the PCM has turned the circuit on, the voltage should approach 0. When the PCM has turned the circuit off, the voltage should approach battery voltage. If the PCM doesn't see the correct voltage under either condition, it sets the code.

DTC 48 = Mass Air Flow (MAF) sensor circuit

When the PCM is receiving pulses from the cam position sensor, it looks for a frequency signal on the wire from the MAF sensor. If no signal from the MAF sensor, it sets the code.

There is no way that an MAF failure would cause the EGR vacuum solenoid fault code. There is no common wiring, and they do not get their 12V power supply from the same fuse.

 

For the egr code Fred,what should i check for so i can clear that code thanks buddy

 

You indicate you replaced the solenoid. The replacement should have a resistance of about 15 ohms. If the solenoid is good, it has to be the wires, corroded or damage harness connector. The EGR solenoid is powered by the same circuit as the EVAP solenoid, skip shift solenoid and reverse lockout solenoid, plus the heaters in the O2 sensors. If the fuse was blown, you should have codes for all of those.

For the wires, with key on you should have 12V on the brown wire at the solenoid connector. The PCM supplies a ground on the gray wire from pin A9. Since EGR is not operated at idle, there's really no way to check for a ground. You have to check continuity of the gray wire between the PCM and the solenoid.

 

Fred i figured out what i did wrong on the egr solenoid i mixed up the 2 hoses it doesn't match the routing on the diagram on my hood,as for the maf my friend is gonna swap his with mine n ill see.thank you on the egr info

 

DTC 27 is only for the electrical circuit. It has nothing to do with whether the hoses are switched, or if the hoses are even attached.

 

Hey Fred i checked the wire n it looks fine,i followed it no rips or tears on it either,um wat else can i look for ;(

 

to add to a code 27, I have my CEL comes on at random times with that code stored. I have verified that I have 37.7ohms on egr solenoid and that I have a good ground wire ( I checked continuity from pcm red connector number 9 to ground wire at erg solenoid). I do notice when KOEO that I only get 11.0-11.3 volts at power wire on erg solenoid without engine running although battery voltage is around 12.2-12.4. with KOER I get 14.0-14.4 volts at battery and 12.9-13.2 volts at egr solenoid power wire.

Is this what could cause light to appear and if so how to address it from here?

 

I can provide you a link to a download of the 94 factory manual.

The diagnostic only references terms like "low (near 0 volts)" when the circuit is
energized, and "high (near battery voltage)" when the circuit is not energized. There is no tolerance stated with regard to voltage.

First test is to supply a ground to see if the solenoid opens.

Second test requires heating the solenoid coil up by applying (isolated from the normal wiring) 12V and ground for 2 minutes. It indicates current should be measured, and should be 0.75 amps or less (but not 0). This is done to determine if there is a partially shorted coil in the solenoid that is drawing excessive amps.

The rest of the procedure is directed at looking for faults in the wiring, connections, PCM pin, etc.