My Grand caravan displays fault codes P0401 & P0406 - Is the code P0406 indicating a failed sensor - Where is this sensors located - Thank you Dan

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.

Hi, sorry I don't have a manual for your van but here is some general information for these codes.

P0126 Insufficient Coolant Temperature for Stable Operation:

basically, the engine is running cool. Check your thermostat to see if it's closing properly. If it is closed when removed, you may want to get a higher temp thermostat. The thermostat is usually in a housing bolted to the engine at the end of the upper radiator hose.


P0406 Exhaust Gas Recirculation Sensor A Circuit High:

This indicates the EGR position sensor signal is out of range. The problem could be the wiring or the sensor itself. Check the wiring first. If it looks good, consider replacing the sensor. I think in your van the sensor may be integrated into the EGR valve itself.

EGR valve:

code #0406 = egr position sensor circuit high ( stuck egr valve or bad egr sensor most likely sensor )

code #2096 = downstream fuel trim system lean ( see next code )

code #0137 = O2 sensor bank 1 sensor 2 circuit low ( replace rear O2 sensor driver side )

code #2299 = brake peddle position/accelerator pedal position incompatible. ( hav you been power braking this truck? ) ( brake light was on wile accelerator was being pushed )

P0405 is an Exhaust Gas Recirculation fault. This could be a faulty valve. You could try cleaning the valve first, chances are it will need to be replaced in the long run. Hope this helps...

It is most likely that your egr needs to be replaced

Here are the links: http://www.obd-codes.com/p0135

http://dodgeforum.com/forum/3rd-gen-ram/26914-p0406-exhaust-gas-recirculation-sensor-a-circuit-high.html

P406 is a EGR code, EGR will also cause a knocking/ pinging sound when there bad. Very common problem. The position sensor inside the valve goes bad. Your going to have to replace the whole EGR valve and it can put out variety of codes from P0401 to P0406. The new valve will solve the problem and easy to replace, you can pick one up at Auto Zone and they can give you the step by step instructions to replacing the EGR with common tools. Good luck and hope this helps.

3.3 engines has the egr valve with transducer.you have to replace the whole unit. code p0406 what its trying to tell you your egr valve circuit is short to ground.it has failed .

egr valve located on front of motor on passenger side mounted to cylinder head below valve cover

Exhaust gas recirculation sensor A (circuit high)
Obviously the sensor or connection is faulty. I'd try cleaning connection with contact cleaner, add some di-electric grease/lube to the connection, check all vacuum lines if applicable & have code erased, and try it.