EGR Valve Problems

[Pyral]

Before I start, I am posting this on Max3rd99 behalf since his account is too new to start new threads. The following is a copy paste of what he wrote on the other 4runner forum.

Hey guys excuse ignorance I just bought a 1999 2.7l and I’m having problems with Egr valve getting codes for it. One mechanic told me Egr valve replacement won’t fix it and another told me to do a delete. I was looking up and reading all these websites to see what to replace the valve or the solenoid, coming up empty and not sure what to do. Been losing power on highway thought this is the cause not sure. Help!

The codes I'm getting are (from FSM):
P0136
Detection Item: Heated oxygen sensor circuit malfunction (bank 1 sensor 2)
Trouble Area: Heated oxygen sensor

P0401
Detection Item: Exhaust Gas Recirculation Flow Insufficient Detected
Trouble Area: 1. EGR valve stuck closed 2. Short in VSV circuit for EGR 3. Open in EGR gas temp sensor circuit 4. EGR hose disconnected 5. ECM

P0402
Detection Item: Exhaust Gas Recirculation Flow Excessive Detected
Trouble Area: 1. EGR valve stuck open 2. EGR VSV open malfunction 3. Open in VSV circuit for EGR 4. Short in EGR gas temp sensor circuit 5. ECM

 

[brillo_76]

What happens when you clean the egr and the tube.

I can't see why cleaning the tubes and or replacing the egr would not fix it..

Car care nut did videos on this on other toyotas.

If the egr is sticking, it may function again if all the carbon is cleaned out of it all.

Granted, what's causing the extra carbon. If it's burning clean and carbon isn't building up in the head cleaning may fix it in my mind.


Sent from my SM-A536V using Tapatalk

 

[Jakeepoo3]

Before I start, I am posting this on Max3rd99 behalf since his account is too new to start new threads. The following is a copy paste of what he wrote on the other 4runner forum.

Hey guys excuse ignorance I just bought a 1999 2.7l and I’m having problems with Egr valve getting codes for it. One mechanic told me Egr valve replacement won’t fix it and another told me to do a delete. I was looking up and reading all these websites to see what to replace the valve or the solenoid, coming up empty and not sure what to do. Been losing power on highway thought this is the cause not sure. Help!

The codes I'm getting are (from FSM):
P0136
Detection Item: Heated oxygen sensor circuit malfunction (bank 1 sensor 2)
Trouble Area: Heated oxygen sensor

P0401
Detection Item: Exhaust Gas Recirculation Flow Insufficient Detected
Trouble Area: 1. EGR valve stuck closed 2. Short in VSV circuit for EGR 3. Open in EGR gas temp sensor circuit 4. EGR hose disconnected 5. ECM

P0402
Detection Item: Exhaust Gas Recirculation Flow Excessive Detected
Trouble Area: 1. EGR valve stuck open 2. EGR VSV open malfunction 3. Open in VSV circuit for EGR 4. Short in EGR gas temp sensor circuit 5. ECM

P0136 is the root cause of all your issues. Either the O2 sensor is faulty or more likely your catalytic converter is going bad. Notice all your other codes are related to exhaust flow and temperature. This will cause poor air fuel ratio and the acceleration issues you describe.

 

[Pyral]

What happens when you clean the egr and the tube.

I can't see why cleaning the tubes and or replacing the egr would not fix it..

Car care nut did videos on this on other toyotas.

If the egr is sticking, it may function again if all the carbon is cleaned out of it all.

Granted, what's causing the extra carbon. If it's burning clean and carbon isn't building up in the head cleaning may fix it in my mind.


Sent from my SM-A536V using Tapatalk

I don't think it's the EGR valve because the 401 and 402 codes state the valve being in 2 separate and opposite states. One says the valve is stuck open and the other says it's stuck closed.

And that wouldn't explain the P0136 code. My guess is it's a bad O2 sensor.

 

[Jakeepoo3]

I don't think it's the EGR valve because the 401 and 402 codes state the valve being in 2 separate and opposite states. One says the valve is stuck open and the other says it's stuck closed.

And that wouldn't explain the P0136 code. My guess is it's a bad O2 sensor.

The o2 sensor can be easily cleaned and tested with a multimeter and propane torch. It may be fine but a clogged cat will throw the sensor readings off. Either one will throw those EGR codes.

 

[brillo_76]

How is the exhaust pressure? you can check that when the engine is cold..
That helps determine if the cat is plugged or not.. IF it matches another rig with the same engine without issues your good.

If its restricted, you make have found your issue..