00 Camry 2.2 egr problem po 401 low flow new egr valve new solenoid new transducer new map clean passages. I don't know what else to do

If you have replaced the EGR valve multiple times and followed the GM trouble chart, but the P0401 insufficient EGR flow code continues to recur on your 2000 Impala LS 3.8, there are a few other things you can check:

1. Check for clogged EGR passages: Make sure that the EGR passages in the intake manifold are not clogged with carbon buildup. Use a vacuum gauge to check for proper vacuum at the EGR valve to ensure the passages are clear.
2. Check the EGR solenoid: Make sure that the EGR solenoid is functioning properly. You can use a multimeter to test the solenoid's resistance and check for proper voltage and ground signals.
3. Check the vacuum supply: Make sure that there is adequate vacuum supply to the EGR valve. A vacuum leak or restriction in the vacuum line can cause insufficient EGR flow.
4. Check the catalytic converter: A clogged or damaged catalytic converter can also cause insufficient EGR flow. You can test the converter's efficiency using a digital thermometer.
5. Check the wiring and connectors: Make sure that all wiring and connectors related to the EGR system are in good condition and properly connected.

If none of these steps resolve the issue, it's possible that there is a problem with the PCM. You may need to have the PCM tested or replaced by a qualified mechanic.

the EGR can be stuck wide open causing the code.

P0401 - Exhaust Gas Recirculation Flow Insufficient Detected

Possible causes - Harness or connectors (EGR volume control valve circuit is open or shorted.)
- EGR volume control valve stuck closed
- EGR volume control solenoid valve
- Dead (Weak) battery
- EGR passage clogged
- Exhaust gas leaks Possible solution - Clean EGR Valve
- Repair EGR harness or connector
- Replaced EGR volume control solenoid valve
- Replaced EGR volume control valve

there's a solenoid under the intake manifold which has vacuum hose connects to egr valve. this solenoid is having a lot of problem.

make sure egr passage way from valve to intake not clogged and make sure exhaust to egr supply is present and make sure if valve is vacuum operated that senser is ok and vacuum supply correct if electial egr senser then intake probably clogged sense code 401 is insuffence egr flow

The EGR and the lift sensor may look perfect from the outside but the under side of the EGR valve and the EGR passage (small tube) are the REAL WORKING parts.

The carbon inside the EGR passage tube and the underside of the EGR valve must to clean out.

Make sure you has a NEW EGR gasket before you start the job.

It's a 2-3 hours job.

If you do not clean the EGR passage tube the Nox emission will get higher (check you past emission reports).

Check for

vacuum leaks on intake manifold,

the air tube between the air filter.

intake manifold vacuum hose.

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clean throttle plate with Berryman carburator cleaner

SEE sample picture HERE
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Also remove carbon built up behind the EGR valve and the EGR passage tube.

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Vacuum leak WILL offset the intended 14.7 to 1 air fuel ratio.

More un-metered air (leaks) will lean out the fuel mixture.

Use small amount of Berryman carb clearer at potential air leak area will help you identify trouble spot.

At idle,just spray and listen for the RPM surge.

The in-rush of carb clearer will increase the RPM on the motor.

Record the problem spot(s) and address it later.

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EGR carbon built up require 2+ hours to clean from start to finish.

You will need a new EGR base gasket before your start.

Locate and remove the EGR valve after the vehicle is cool down.

Carefully record the connector and vacuum line (for older vehicle) location by drawing an easily to follow diagram.

Remove the EGR valve.

Inspect the location of the carbon built-up inside the valve and the EGR passage tube.

SOAK these areas with WD-40 spary.

You will need a small screwdriver,cloth hanger and lot of newspaper and time to get this cleaning done right.

RE-SOAK the carbon and let it sit for over-night will also help.

One the last round,pass a shop vacuum of the EGR valve and the passage pipe.

Install the new EGR gasket and connectors.

Allow the vehicle to warm up outdoor to burn up any remaining WD-40.


Take it for a test drive.


Please rate my answer if it's useful to you.


Cheers,

Mustgo

egr position sensor. check items before you replace them, it gets expensive just guessing.

Chrysler Concorde 1993-1997 3.5L MFI 6cyl
Exhaust Gas Recirculation System
Operation
This system reduces the amount of oxides of nitrogen (NO x ) in the exhaust by allowing a predetermined amount of exhaust gases to recirculate and dilute the incoming fuel/air mixture. The diluted air/fuel mixture reduces peak flame temperature during combustion, which in turn inhibits the production of Nitrogen oxides. The principal components of the system are:
- EGR tube (connects a passage in the intake manifold to the exhaust manifold)
- EGR valve
- Electronic EGR Transducer
- Vacuum hoses


Component and System Testing

1. Check the condition of all of the EGR system hoses and tubes for leaks, hardening or kinks on the rubber hoses. Repair and correct these conditions before proceeding any testing.
2. Be sure that the hoses at both of the EGR valve and EGR valve control are connected to the proper fittings.
3. Be sure the electrical connector is firmly attached at the valve control.
4. To check the EGR system operation, connect the DRB III scan tool or equivalent to the 16-way data link connector. The data link connector is located on the lower edge of the instrument panel near the steering column. Follow the scan tool instructions.
5. After checking the system with the DRB III scan tool, proceed to the EGR valve leak and control tests, then repair as necessary.

Removal & Installation
EGR Valve and Transducer



EGR valve and transducer assembly-3.5 engine




The EGR valve attaches to the back of the cylinder head-3.5L engine




Loosen, but do not remove, the EGR tube to intake manifold screws

The EGR valve attaches to the rear of the right cylinder head.

1. Remove the vacuum tube from the electric EGR transducer solenoid. Inspect the vacuum lines for cracking, poor seal due to hardness, or other problems. Replace with new hoses if necessary.
2. Remove the electrical connector from the solenoid.
3. Slide the transducer up and out of the mounting bracket.
4. Loosen, but do not remove, the EGR tube to the intake manifold screws.
5. Remove the EGR tube lower screws at the valve.
6. Remove the EGR valve and transducer.
7. Clean both gasket surfaces and check for any signs of leakage or cracks. Replace the components if any such damage is found or if the valve fails the tests.

To install:

1. Loosely install the EGR valve and a new gasket onto the cylinder head.
2. Using a new gasket, attach the EGR tube to the valve and tighten the screws to 95 inch lbs. (11 Nm).
3. Tighten the EGR tube to the intake manifold plenum screws to 16 ft. lbs. (22 Nm).
4. Tighten the EGR valve to the cylinder head screws to 16 ft. lbs. (22 Nm).
5. Reconnect the transducer solenoid to the vacuum fitting on the manifold.
6. Slide the transducer into the bracket.
7. Reconnect the vacuum lines and electrical wires to the EGR transducer.

continue...

P0400 = EGR Flow
P0325 = knock sensor (Do not ever change a knock sensor, they don't affect anything and cost $600 to replace for absolutely no gain)
P1200 = I can't find this one. I think it's injector flow
report back on what you find.
Egr flow may be plugged egr passages or a bad solenoid.
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1996 PCED OBDII-Villager SECTION 1B: Description and Operation
Exhaust Gas Recirculation System
Exhaust Gas Recirculation (EGR) System Operation The exhaust gas recirculation (EGR) system (Figure 1 below) recirculates a portion of the exhaust gases into the intake manifold under average vehicle driving conditions to reduce combustion temperatures and exhaust gas NOx content. The amount of exhaust gas recirculated varies according to operating conditions and will be cut completely under:

• Engine starting condition
• Low engine coolant temperature condition
• Excessively high engine coolant temperature condition
• Engine idling condition
• High engine speed condition
• Mass air flow sensor failure

The exhaust gas recirculation (EGR) system on the Villager uses the exhaust gas recirculation/evaporative emission (EGR/EVAP) control solenoid valve to provide vacuum to both the EGR valve and the EVAP canister when commanded by the PCM. If the exhaust backpressure is sufficient to close the EGR backpressure transducer valve, vacuum is sent to the EGR valve and allows EGR gas to flow into the intake manifold. If the exhaust backpressure is not sufficient, the EGR backpressure transducer will remain open and allow vacuum from the EGR/EVAP control solenoid to vent to the atmosphere.
The EGR system monitor, for OBD II regulations, uses an EGR temperature sensor to monitor the EGR system. The EGR temperature sensor is a thermister located in the EGR passageway. When hot exhaust gas is recirculated into the engine, the temperature at the EGR passageway increases. This increase is sensed by the EGR temperature sensor and a signal is sent to the PCM to indicate EGR flow. If the EGR temperature sensor does not detect EGR flow when commanded by the PCM after two consecutive drive cycles, the malfunction indicator lamp (MIL) will be illuminated and a diagnostic trouble code (DTC) will be stored. The MIL will be turned off after three consecutive drive cycles are completed with no malfunctions detected. The DTC will remain stored in the PCM memory until 80 drive cycles have been completed without the same malfunction detected in the system.
Figure 1: Exhaust Gas Recirculation (EGR) System Diagram Item Number Description 1 — EGR/EVAP Control Solenoid 2 — Air Cleaner Housing 3 — Throttle Valve 4 — EGR Temperature Sensor 5 — EGR Valve 6 — EGR Backpressure Transducer 7 — EVAP Canister
Exhaust Gas Recirculation (EGR) Backpressure Transducer Valve The exhaust gas recirculation (EGR) backpressure transducer valve is used to control EGR. The EGR valve is operated by ported vacuum, but the ported vacuum will normally be vented off at the EGR backpressure transducer valve. As rpm increases, exhaust pressure increases and pushes on the diaphragm in the EGR backpressure transducer valve and closes the vacuum vent.
Figure 2: EGR Backpressure Transducer Value
Item Number Description 1 — Throttle Valve 2 — Vacuum Port 3 9D475 EGR Valve 4 9F452 EGR Backpressure Transducer Valve 5 — EVAP Canister 6 — EGR/EVAP Control Solenoid 7 — Vent
EGR/EVAP Control Solenoid The exhaust gas recirculation/evaporative emission (EGR/EVAP) control solenoid (Figure 3) is controlled by the powertrain control module (PCM). The EGR/EVAP control solenoid controls vacuum to both the exhaust gas recirculation (EGR) valve and to the evaporative (EVAP) emission canister. When the EGR/EVAP control solenoid is off (12 V signal from the PCM) vacuum is supplied to both the EGR valve and to the EVAP canister. When the EGR/EVAP control solenoid is on (ground supplied by PCM) vacuum is vented to the atmosphere keeping the EGR valve closed and no vacuum to the EVAP canister. The PCM will command the EGR/EVAP control solenoid on at:

• Engine starting condition
• Low engine coolant temperature condition
• Excessively high engine coolant temperature condition
• Engine idling condition
• High engine speed condition
• Mass air flow sensor failure

Figure 3: Exhaust Gas Recirculation/Evaporative Emission (EGR/EVAP) Control Solenoid
Exhaust Gas Recirculation (EGR) Temperature Sensor
The exhaust gas recirculation (EGR) temperature sensor (Figure 4) is a thermister type sensor that monitors the temperature of the exhaust in the EGR passageway. As the EGR flow increases, the temperature increases. This process creates a change in the resistance of the sensor, which decreases as the temperature increases. The signal is sent to the powertrain control module (PCM) to indicate that the EGR system is working properly. If the EGR temperature sensor does not change resistance as the PCM expects on two consecutive drives, the malfunction indicator lamp (MIL) will be illuminated and a diagnostic trouble code (DTC) will be stored.
Figure 4: EGR Temperature Sensor Exhaust Gas Recirculation (EGR) Valve
The exhaust gas recirculation (EGR) valve (Figure 5) recirculates portions of the exhaust gas back into the intake manifold to reduce the amount of the NOx released during combustion and to reduce combustion temperature. The amount of exhaust gases that are released into the engine is proportional to the load on the engine.
Figure 5: EGR Valve