Lexus p0400 code

The fault is somewhere around the EGR valve - probably the EGR valve or the throttle position sensor.

Before replacing any sensors try removing and cleaning the EGR.

Here's a Youtube link that may be of help to you:

1999 maxima egr Google Search

This link explains about the EGR:
P0400 Exhaust Gas Recirculation Flow Malfunction

CEL code P0400 EGR Flow Malfunction

P0400 Exhaust Gas Recirculation Flow Malfunction
P0235 Turbocharger Supercharger Boost Sensor Circuit Malfunction

I would say the EGR Valve is faulty- stuck open. I think the second code ( P0235) is being generated due to the EGR problem.

code p0400 refers to exhaust gas recirculation(EGR) system---flow malfunction.===causes---hose leak/blockage--basic setting not carried out (if applicable)---wiring---EGR valve ---EGR solenoid---ECM
check out the valve and solenoid.

EGR malfunction. Check the vacuum hose to the EGR valve first.

the SES lamp (aka. CEL and MIL)
means Scan it,
is this a USA car? or canada.
how you scan CARs varies by COUNTRY , unstated.
In the usa, this car has 2 engines.
1.6L and 1.8L, the latter is DOHC sport.
but in both cases here, all scan tools work , this old.

1. all autoshops can scan it.(some free)
2. all autostores (most) can scan it. free.
3. many outstores here can loan you the scan tool. OBD2.
4. you can buy a tool for $9 (ask) off fleabay.
5. or buy the code reader, for $20 off Amazon.

true for all cars USA, and 1998 and newer in Canada.
my guess is said tool will throw DTC P0400 or more.

the 1.6L G16B engine loves to die.
it loves to have the main EGR valve stick, 1000s seen.
we clean it until its Snappy, and stalls end.

the valve is way far behind the intake manifold on the #4 intake runner.
and dont stap the bolts, ask how not to.....

P0400 - Exhaust Gas Recirculation Flow Malfunction
The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount of exhaust gases that re-enter the cylinders. The powertrain control module (PCM) determines how much based on engine load, temp, and other conditions. If the PCM detects that the amount of exhaust gases entering the cylinder were insufficient or non-existent, this code is set.

Symptoms: No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However, non visible symptoms will be increased combustion temperature and increased Nox emissions.

Causes: A code P0400 may mean that one or more of the following has happened:
Plugged EGR passage which restricts the flow of exhaust gasses
Faulty EGR solenoid
Faulty EGR solenoid wiring/harness
Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
Faulty EGR valve

Possible Solutions: Since EGR valve designs are different, no one test will suffice:
Using a scan tool, operate the EGR valve with the engine running. If the engine stumbles, the problem was likely intermittent wiring problem or intermittent blockage problem
If engine doesn't stumble, operate the EGR valve manually, if possible. If engine doesn't stumble and die, the ports are likely plugged. Removal of valve and cleaning of all ports will be required
Checking of solenoid can only usually be done with a scan tool, because most solenoids operate with a duty cycle of voltage, rather than constant voltage
Check all vacuum lines, hoses, etc for any damage
Visually inspect the solenoid harness and the solenoid for damage
Replace EGR valve

Hope this helps.

A code P0400 may mean that one or more of the following has happened:
• Plugged EGR passage which restricts the flow of exhaust gasses
• Faulty EGR solenoid
• Faulty EGR solenoid wiring/harness
• Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
• Faulty EGR valve

P0400 - Exhaust Gas Recirculation Flow Malfunction

The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount of exhaust gases that re-enter the cylinders. The powertrain control module (PCM) determines how much based on engine load, temp, and other conditions. If the PCM detects that the amount of exhaust gases entering the cylinder were insufficient or non-existent, this code is set.
Symptoms:
FB.init("dd7d9e9681341cde77587bc6a2029f6f"); OBD-Codes.com on Facebook No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However, non visible symptoms will be increased combustion temperature and increased Nox emissions.

Causes: A code P0400 may mean that one or more of the following has happened:

• Plugged EGR passage which restricts the flow of exhaust gasses
• Faulty EGR solenoid
• Faulty EGR solenoid wiring/harness
• Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
• Faulty EGR valve

Possible Solutions: Since EGR valve designs are different, no one test will suffice:

• Using a scan tool, operate the EGR valve with the engine running. If the engine stumbles, the problem was likely intermittent wiring problem or intermittent blockage problem
• If engine doesn't stumble, operate the EGR valve manually, if possible. If engine doesn't stumble and die, the ports are likely plugged. Removal of valve and cleaning of all ports will be required
• Checking of solenoid can only usually be done with a scan tool, because most solenoids operate with a duty cycle of voltage, rather than constant voltage
• Check all vacuum lines, hoses, etc for any damage
• Visually inspect the solenoid harness and the solenoid for damage
• Replace EGR valve

Hope helps (remember comment and rated this).

the passage that causes this low flow is in the intake, it gets full of carbon and gunk, try running a wire through it, also make sure the EGR passes a functional test.

P00A0 is a factory readable only code (i.e. only ford dealers have the computer to read it)
the P0400 is a generic E.G.R. flow restriction code. so yes a dvom (multimeter) and a vacuum pump to diagnose it correctly, also check for loose wires as ford harness connectors are known to fail alot due to crappy phenolic content in the plastic and heat combined they can warp and / or corrode the contacts