How can i test the EGR valve on my 89 G20 van? a guy said try disconnecting and plugging the vacuum hose going to the EGR valve and then what? if the engine turn off its ok? if not its ok? thanks for the help

That's not what this code is about .P0401 - EGR Flow Insufficient Detected . Probably clogged egr passages .
P0401 - EGR Flow Insufficient Detected The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum.

• Vacuum supply
• EGR valve stuck closed
• EGR valve leaks vacuum
• EGR flow path restricted
• EGRVR circuit shorted to PWR
• VREF open to D.P.F. EGR sensor
• D.P.F. EGR sensor downstream hose off or plugged
• EGRVR circuit open to PCM
• VPWR open to EGRVR solenoid
• D.P.F. EGR sensor hoses both off
• D.P.F. EGR sensor hoses reversed
• Damaged EGR orifice tube
• Damaged EGRVR solenoid
• Damaged PCM

Perform KOER self-test and look for DTC P1408 as an indication of a hard fault. If P1408 is not present, look for contamination, restrictions, leaks, and intermittents.

look under hood on engine compartment for emission vacuum hose routing it can help you locate vacuum hose location to the egr valve

My first thought would be a vacuum leak in one of the hoses. Rubber hoses get brittle with age and even a small crack in a hose may cause surging. Happened to me in a Lumina.

Disconnect vacuum supply hose to EGR V.R. solenoid at the solenoid. Connect the vacuum supply hose to a vacuum gauge. Start engine and check the vacuum at idle. Is the supply vacuum greater than 10 in-Hg (34 kPa) ?

OK, if you replaced the EGR hose, did you go all the way to change the EGR Valve? A stuck open EGR Valve can cause a rough idle and almost make it cut off.
Also, a vacuum leak on the EGR valve can cause a rough idle.

Exhaust Gas Recirculation (EGR) Valve Removal & Installation 2.0L Zetec Engine NOTE: When the EGR tube is disconnected from the EGR valve, it must be discarded and a new EGR tube must be installed. The aluminum threads on the EGR valve must be inspected, and a new EGR valve installed if the threads are damaged.
To Remove:

1. Disconnect the negative battery cable.
2. Remove and discard the exhaust manifold-to-EGR tube. Use the following as a guide:
3. Raise and safely support the vehicle
4. Remove the splash shield
5. Disconnect the EGR tube fitting
6. Lower the vehicle
7. Remove the air cleaner outlet pipe
8. Disconnect the EGR tube from the EGR valve.
9. Detach the vacuum line and remove the two retainer bolts.

NOTE: The EGR valve sealing surfaces are soft metals and easily damaged.
To Install:

1. Installation is a reverse of the removal process. Carefully clean all sealing surfaces and install a new EGR valve gasket.
2. Install a new EGR valve tube.

Detach the vacuum line (#1) and unbolt the EGR valve - 2.0L

3.0L (4v) Engine To Remove:

1. Disconnect the vacuum line.
2. Disconnect the EGR tube.
3. Remove the EGR valve and discard the gasket.

NOTE: The EGR valve sealing surfaces are soft metals and easily damaged.
To Install:

1. Installation is a reverse of the removal process. Carefully clean all sealing surfaces and install a new EGR valve gasket.

Detach the vacuum line (#1), unthread the EGR tube (#2) and remove the EGR valve bolts (#3) - 3.0L (4V)

EGR Valve Testing

1. Install a tachometer on the engine, following the manufacturer's instructions.
2. Detach the engine wiring harness connector from the Idle Air Control (IAC) solenoid.
3. Disconnect and plug the vacuum supply hose from the EGR valve.
4. Start the engine, then apply the parking brake, block the rear wheels and position the transmission in Neutral.
5. Observe and note the idle speed.
   

If the engine will not idle with the IAC solenoid disconnected, provide an air bypass to the engine by slightly opening the throttle plate or by creating an intake vacuum leak. Do not allow the idle speed to exceed typical idle rpm.
Using a hand-held vacuum pump, slowly apply 5-10 in. Hg (17-34 kPa) of vacuum to the EGR valve nipple.

1. If the idle speed drops more than 100 rpm with the vacuum applied and returns to normal after the vacuum is removed, the EGR valve is OK.
2. If the idle speed does not drop more than 100 rpm with the vacuum applied and return to normal after the vacuum is removed, inspect the EGR valve for a blockage; clean it if a blockage is found. Replace the EGR valve if no blockage is found, or if cleaning the valve does not remedy the malfunction.

EGR Valve Removal & Install
3.0L OHV (2 valve) and 3.4L SHO engines



Fig. : EGR mounting-3.0L OHV (2 valve) engine



Fig. : EGR mounting-3.4L (SHO) engine



Fig. : Remove the two retaining bolts and...



Fig.: ... remove the valve from the intake manifold



Fig.: Thoroughly clean the mating surfaces of the manifold and the EGR valve (if being reused)

1. Disconnect the negative battery cable.
2. Remove the vacuum hose from the EGR valve.
3. Using a 22mm wrench or crowfoot, disconnect the EGR valve-to-exhaust manifold tube from the EGR valve.
4. Remove the EGR valve mounting fasteners, then separate the valve from the intake manifold.
5. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
   

To install:

1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts to 15-22 ft. lbs. (20-30 Nm).
2. Connect the EGR valve-to-exhaust manifold tube to the valve, then tighten the tube nut to 26-47 ft. lbs. (35-65 Nm).
3. Connect the vacuum hose to the EGR valve.
4. Connect the negative battery cable.

3.0L OHC (4 valve)



Fig. : EGR mounting-3.0L OHC (4 valve) engine

1. Disconnect the negative battery cable.
2. Remove the vacuum hose from the EGR valve.
3. Remove the two EGR tube-to-EGR valve retaining nuts.
4. Remove the EGR valve mounting fasteners, then separate the valve from the intake manifold.
5. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
   

To install:

1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts to 15-22 ft. lbs. (20-30 Nm).
2. Connect the EGR valve-to-EGR tube, then tighten the retaining nuts.
3. Connect the vacuum hose to the EGR valve.
4. Connect the negative battery cable.

Tell us news.

sorry need to have a play with it to find the fault ,but if this vehicle is playing up why not go green and get yourself a nice peugeot partner van or a ford courier something with a nice 1.6 diesel engine ,50+mpg what more could you want .especially if your petrol prices were instantly risen to our europeon prices and the road tax set at our levels for engines this size

put a new BPT hose vacum line hose.

Vitally

Exhaust Gas Recirculation (EGR) System Monitor—Differential Pressure Feedback EGR The Differential Pressure Feedback EGR System Monitor is an on-board strategy designed to test the integrity and flow characteristics of the EGR system. The monitor is activated during EGR system operation and after certain base engine conditions are satisfied. Input from the ECT, CHT, IAT, TP and CKP sensors is required to activate the EGR System Monitor. Once activated, the EGR System Monitor will perform each of the tests described below during the engine modes and conditions indicated. Some of the EGR System Monitor tests are also performed during on demand self-test.

1. The differential pressure feedback EGR sensor and circuit are continuously tested for opens and shorts. The monitor looks for the Differential Pressure Feedback EGR circuit voltage to exceed the maximum or minimum allowable limits.
   
   The DTCs associated with this test are DTCs P1400 and P1401.

1. The EGR vacuum regulator solenoid is continuously tested for opens and shorts. The monitor looks for an EGR Vacuum Regulator circuit voltage that is inconsistent with the EGR Vacuum Regulator circuit commanded output state.
   
   The DTC associated with this test is DTC P1409.

1. The test for a stuck open EGR valve or EGR flow at idle is continuously performed whenever at idle (TP sensor indicating closed throttle). The monitor compares the Differential Pressure Feedback EGR circuit voltage at idle to the Differential Pressure Feedback EGR circuit voltage stored during key on engine off to determine if EGR flow is present at idle.
   
   The DTC associated with this test is DTC P0402.

1. The differential pressure feedback EGR sensor upstream hose is tested once per drive cycle for disconnect and plugging. The test is performed with EGR valve closed and during a period of acceleration. The PCM will momentarily command the EGR valve closed. The monitor looks for the differential pressure feedback EGR sensor voltage to be inconsistent for a no flow voltage. A voltage increase or decrease during acceleration while the EGR valve is closed may indicate a fault with the signal hose during this test.
   
   The DTC associated with this test is DTC P1405.

1. The EGR flow rate test is performed during a steady state when engine speed and load are moderate and EGR vacuum regulator duty cycle is high. The monitor compares the actual Differential Pressure Feedback EGR circuit voltage to a desired EGR flow voltage for that state to determine if EGR flow rate is acceptable or insufficient. This is a system test and may trigger a DTC for any fault causing the EGR system to fail.
   
   The DTC associated with this test is DTC P0401. DTC P1408 is similar to P0401 but performed during KOER Self-Test conditions.

1. The MIL is activated after one of the above tests fails on two consecutive drive cycles.
   

EGR Vacuum Regulator Solenoid The EGR vacuum regulator solenoid (Figure 88) is an electromagnetic device which is used to regulate the vacuum supply to the EGR valve. The solenoid contains a coil which magnetically controls the position of a disc to regulate the vacuum. As the duty cycle to the coil increases, the vacuum signal passed through the solenoid to the EGR valve also increases. Vacuum not directed to the EGR valve is vented through the solenoid vent to atmosphere. Note that at 0% duty cycle (no electrical signal applied), the EGR vacuum regulator solenoid allows some vacuum to pass, but not enough to open the EGR valve.


Exhaust Gas Recirculation (EGR) Vacuum Regulator Solenoid Removal and Installation

1. Disconnect the battery ground cable (14301). For additional information, refer to Section 414-01 .

1. Disconnect the vacuum hoses and the EVR solenoid electrical connector.

1. Remove the two nuts and the EVR solenoid (9J459).

From the looks of the rubber mounting, I would say it's mounted on the cowl (firewall) on the passenger side in the engine compartment.

Please rate as fixya if this helps. Thanks

Stuck closed. You can't free these up. Gotta buy a new one.