Ok, I had a check engine light with a P0400 (EGR malfunction) code. I was able to clear it but it would come right back. So, I took off the EGR valve (found the vacuum line going to it was broken) and cleaned the valve and the manifold as well. I also tested the valve with a vacuum pump and it was working properly. After replacing the vacuum line going to the EGR valve, and installing a new gasket, I put it all back together. Result......P400 code comes back after about 4 minutes of driving.

The valve works properly when vacuum is applied, and it is clean inside and out. Any ideas on when to start looking next.

Thanks,

Glenn

 

Forgot to mention, this is on the 95 850 Turbo. Car runs great, no issues except that damn check engine light staring at me all the time <grin>

 

Here's the diags from the manual:
============================
Code 2-4-1 (EGR System, Flow Malfunction)
1) Turn ignition on. Use Volvo Scan Tool (998-8686) parameter
Diagnostic Test Mode No. 3 and check EGR controller functions. If EGR
controller operates, go to next step. If EGR controller does not
operate, go to step 7).
2) Turn ignition off. Disconnect wire at EGR controller
connector terminal No. 2. Connect a jumper wire between EGR controller
connector terminal No. 2 and ground. Start engine and run at idle. If
engine runs unevenly at idle, fault is intermittent. Go to step 11).
If engine does not run unevenly at idle, go to next step.
3) Turn ignition off. Carefully remove White hose from EGR
controller. Connect vacuum gauge to White hose. Start and run engine
at idle. If vacuum gauge gives any reading, go to next step. If vacuum
gauge does not give a reading, ensure White vacuum hose and connection
to intake manifold are not blocked.
4) Start and run engine at idle. Connect White hose to EGR
controller. Carefully disconnect Yellow hose from EGR controller.
Connect a vacuum gauge to EGR controller connector. Connect loose wire
on EGR controller to ground so as to open EGR controller. If vacuum
gauge gives any reading, go to next step. If vacuum gauge does not
give a reading, retest using new EGR controller.
5) Turn ignition off. Carefully disconnect Yellow hose from
EGR valve. Check Yellow hose for leaks or obstruction. Repair as
necessary. If hose is okay, go to next step.
6) Turn ignition off. Connect Yellow hose to EGR valve.
Connect vacuum pump to Yellow hose at EGR controller. Start engine and
run at idle. Pump vacuum to maximum of 4.35 psi (30 kPa). Check that
EGR valve retains vacuum. Engine should run unevenly when vacuum pump
shows negative pressure. If engine runs evenly when vacuum pump shows
negative pressure but vacuum pump loses vacuum, test using new EGR
valve. If engine runs smoothly at idle when vacuum pump shows negative
pressure and vacuum pump retains vacuum, check if EGR pipe is clogged.
Repair as necessary. If EGR pipe is okay, retest using new EGR valve.
7) If EGR controller does not operate, turn ignition off.
Disconnect EGR controller connector. Turn ignition on. Connect
voltmeter between EGR controller connector terminal No. 1 and ground.
If battery voltage is present, go to next step. If battery voltage is
not present, check wiring between EGR controller connector terminal
No. 1 and main relay connector terminal No. 3 for an open circuit.
8) Turn ignition off. Disconnect EGR controller connector.
Disconnect ECM connector. Connect breakout box to ECM connector.
Reconnect ECM. Connect ohmmeter between breakout box pin No. 40 and
EGR controller connector terminal No. 2. If ohmmeter reads zero ohms,
go to next step. If ohmmeter does not read zero ohms, check wiring
between EGR controller connection terminal No. 2 and breakout box pin
No. 40 for an open circuit.
9) Turn ignition on. Disconnect EGR connector. Connect
voltmeter between breakout box pins No. 40 and 42. If voltmeter reads
less than one volt, go to next step. If voltmeter does not read less
than one volt, check wiring between EGR controller connector terminal
No. 2 and breakout box pin No. 40 for a short circuit to voltage.
10) Turn ignition off. Ensure EGR connector is connected.
Turn ignition on. Use Volvo Scan Tool (998-8686) to check if EGR
controller functions. If EGR controller functions, code was caused by
poor contact in control module and/or EGR controller connector. Repair
as necessary. If EGR controller does not function, retest using new
EGR controller.
11) If fault is intermittent, check EGR controller connection
and ECM connectors for signs of loose connection and contact
resistance. Check wiring between EGR controller connector terminal No.
2 and ECM connector terminal No. 40 for an intermittent open circuit.
Also check wiring between EGR controller connector terminal No. 1 and
main relay connector terminal No. 3 for an intermittent open circuit.

 

Thanks, That definitely a next step to start on

Glenn

 

Need help: 96Volvo 850GLT non turbo: Check Engine Lite came on. Code reader state P400-Exhaust Recirculation Flow. Also there is a slight smell of exhaust in closed car. Appreciate very much any ideas you may have.

 

When was the last time your PCV system was replaced? Also, check all vacuum lines leading to the EGR. Do you have a EGR?

 

Step One: Take off the EGR valve. Look for vacuum line going to it to see if it's broken anywhere. Clean the valve and the manifold as well. Test the valve with a vacuum pump and see if its working properly. Using a new gasket, put it all back together.

Step Two: Clear code.

Step Three: check your exhaust system to see if you might have a small leak someplace. If you have a manifold gasket leaking on the back of the block it might be that exhaust fume getting sucked into the heating & AC plenum at the base of the windshield on the passenger side.

That slight smell of exhaust might be a small oil leak and the oil "cooking" off the engine and getting sucked into the heater intake.

 

@ Glenn: Did you ever get that EGR taken care of? I had the code last summer before I did my PCV system. I took it off, cleaned it up real good and when I put it all back together it went away.

Today the darn code came back... I'm thinking a vacuum line came loose but I haven't checked yet. Will check tomorrow. Just wondering how deep you had to dig, those instructions GDog posted are intimidating...

 

I'm not sure if the ECU would have any idea that an EGR vacuum line has come loose, or at least it should not trigger an EGR DTC (maybe a lean code). The P0400 code should be caused by the EGR controller circuit, in other words, steps 7-11 in the above diagnostic.

The EGR is completely disonnected in my NA 850. The vacuum lines are removed/plugged and the valve too (although i think it's normally closed anyhow with no vacuum pressure). The controller still has its wiring harness attached and as far as the ECU knows, it functions perfectly. No CEL.

Don't tell the EPA.

 

Popped the hood and found the vacuum elbow at the top of the EGR valve torn. Replaced it today and will see if the code comes back.

 

Where are you at with yours ??

 

I had the same thing, a P0400 and the bad smell coming into the cabin. I pulled the EGR cleaned it, cleaned the throttle body and put it all back together last weekend.
I noticed there was a hard plastic hose that ran from under the intake manifold around the right side of the engine and down to the intake pipe, this is completely severed and leaking oil ( I presume crankcase vapours). I've found out this is fairly common, you may want to check that.
On another note I now have a P1418 code and am stumped by that.

 

That is your PCV system. You need to replace that ASAP.

 

Did a little more research and this is from Volvo so "final answer"

OBDI code 413 is the same as OBDII "P" code P1416,P1417 and P1418. It is a EGR temperature sensor signal absent or faulty.

 

Changed all the plastic hard lines and rubber hoses going to the EGR. All is ok now!