View Full Version : 1995 Tercel EGR Fault

06-11-2011, 07:50 PM
Hey guys,
I have a question about an EGR fault my sisters Tercel has been throwing. The code is P0401-EGR insufficent flow.

My dad a few weeks back was told by the local auto parts store that the code means the EGR is not working properly. Under that assumption he replaced the modulator, VSV, and EGR valve itself. Well this didn't fix the problem and the fault returned.

I went digging into the problem this morning and checked to make sure all vacuum lines were clear, the EGR was operating correctly, and checking the charcoal canister. While I was testing the charcoal canister, air does not flow out of the purge valve when I apply low compressed air to the tank port. Air does flow out of the bottom vent of the canister. It seems to me the canister is bad.

Looking at the diagram it, I think the CEL (insufficent flow) could be the result of the canister not operating correctly? I could use some help with this issue.

06-11-2011, 08:03 PM
I don't know about the 1995 Tercel engine, mine is a 5SFE and on it the charcoal canister isn't really connected to the engine. When the engine is off it is taking fumes from the fuel tank and filtering them through the charcoal. There is a BVSV vacuum valve connected to one of the coolant lines that senses engine temperature. Once the vehicle is running and the temperature has heated up, it opens the valve thereby allowing the stored excess fumes from the canister to flow into the intake manifold and be burned off by the engine. The later model canisters have a purge valve on the bottom that exits through a hose out the driver's side wheel well. Long story short I don't think that the canister would throw an insufficient flow code. If I'm wrong, someone educate me- I'm more than willing to learn. Good luck with your issue.

06-11-2011, 08:55 PM
The carcoal canister isnt part of the EGR anyways. Its part of the EVAP system, so it couldnt be your problem.

It sounds to me like the EGR system is gunked up. Im not sure about this particular system, but most have a metal line running from the exhaust side of the head, or the exhaust manifold. It connects the valve to the exhaust system flow. This line can get clogged up. Some systems have the line built into the head, basically a tunnel for exhaust gas to flow from the exhaust side to the intake side with the EGR valve bolted up on the intake manifold. This tunnel could be clogged. Remove the valve and see where the exhaust gases are coming from and see if you can blow air thru it. If the engine has been buring oil it can clog up the EGR system pretty quick.

It could be lots of other things, but assuming everything is hooked up properly and the new parts are not faulty, this would be my guess.

06-12-2011, 09:34 PM
Thanks for the help...I know the evaporation system is not apart of the egr system but I don't have much experience working withe the systems. Just thought since they are both run with vacuum maybe they are connected somehow. I don't know how my dad went about cleaning or installing the egr parts but I will double check it all. She is burning quite a bit of oil which maybe the cause. Ill take a look

06-15-2011, 12:48 AM
tercels are very bad about oil consumption. so yeah it may have clogged your egr