Trouble CodeFault LocationProbable Cause
P0406 Exhaust gas recirculation (EGR) valve place sensor A high intake Wiring brief to positive, EGR valve place sensor, ECM

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What Does code P0406 Mean?

In the internal burning engine, the appropriate chemical reaction of combustion is as follows: oxygen (O2) + fuel (HC) = carbon dioxide (CO2) + water (H2O). Unfortunately, since engines are offered over such a wide range of situations, ideal combustion often challenging to achieve. Exterior of the lab, for example, over there is a wide range of ambient temperature and humidity conditions, atmospheric pressure changes, and differing driver demands and even the state of the engine itself, every one of which have the right to lead come less-than-ideal combustion. Modern engines rental a number of strategies to achieve ideal burning in ever-changing circumstances, using systems choose variable valve timing and also lift, variable ignition timing, straight fuel injection, and also exhaust gas recirculation (EGR), to surname a few.

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The EGR mechanism is design to alleviate the production of nitrogen oxides (NOx), which space responsible because that the formation of smog and also acid rain (Nitric mountain – HNO3), amongst other environmental and health hazards. Under right conditions, nitrogen (N2) would usually not react through the oxygen throughout combustion, but abnormally-high combustion temperatures, typically over 2,400 °F, can allow N2 reactions and the development of NOx. The EGR device injects a little amount of invested exhaust gases, routed native the exhaust pipe, earlier into the intake, to reduce the amount of O2 easily accessible for combustion, because of this reducing burning temperatures and the manufacturing of NOx.

The EGR mechanism connects the exhaust come the entry via pipes and also a valve. The EGR valve used to be vacuum-modulated, however many vehicles have actually switched over to electronic control by the engine regulate module (ECM). Depending on demand, the ECM commands the EGR to open and close, regulating the flow of exhaust gas right into the intake. The ECM likewise uses sensors come monitor device function, such together the EGR Temperature or circulation Sensor and also EGR position sensor. If the ECM detects a trouble in the EGR place sensor circuit, it will set a diagnostic trouble code (DTC) and also illuminate the malfunction indicator lamp (MIL).


What room the common reasons of password P0406 ?

Depending on year, make, and model, DTC P0406 might have variety of causes. Below are few of the many common.

Sensor fault – because it is continuous subjected to warmth from the exhaust, internal electrical faults room a typical occurrence. Replace the sensor, clean the code, keep driving.Circuit trouble – details repair procedures might require disconnecting the EGR place sensor or interfering with its harness. Poor connections, poor routing, chafing, open and short circuits space par because that the course. Repair as needed.Dodge / Chrysler / Jeep / lamb / MOPAR – A variety of models in this lineup have actually released TSBs (technical organization bulletins) addressing DTC P0405 / P0406. Reprogramming the ECM fixes the problem. Examine with her dealership to watch if your vehicle is covered by any kind of of these TSBs.

What room the symptoms of code P0406 ?

Aside native the MIL, you will most likely not notice any drivability problems associated with this certain EGR DTC. Still, since the ECM is currently running in “limp-home mode,” girlfriend may notice a slight drop in performance and also fuel economy.

How perform you troubleshoot password P0406 ?

Because this DTC describes a circuit problem, you’ll require a vehicle-specific EWD (electrical wiring diagram) and also a DMM (digital multimeter) come diagnose it.

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General check – examine the cable harness for apparent damage, such together from chafing or burns, i m sorry may cause circuit problems. Also, examine for bending or broken pins, corrosion, or proof of water entry. Repair together necessary and make certain connectors are appropriately seated.EGR place Sensor examine – many EGR position sensors room the three-pin type: reference voltage (Vref), Ground, and Signal. In the situation of ours Toyota EWD, these space VC, E2, and EGLS, respectively.If the EGR valve is vacuum-actuated, you deserve to bench-test the position sensor with a DMM and vacuum-pump. Disconnect the connector and also measure throughout the whole circuit (VC-E2), and you must measure something choose 6 kΩ (6,000 Ω). On the signal wire, measuring between VC and also EGLS, you need to measure somewhere in between 0.1 kΩ and also 5.5 kΩ (100 Ω and 5,500 Ω), depending on how lot vacuum you apply to the actuator port.If the EGR is electronically-actuated or you desire to inspect output voltages, backprobe the connector through you DMM and also measure voltage with KOEO (key ~ above engine off). VC should measure somewhere between 4.5 V and 5.5 V and also E2 have to measure 0 V. ELGS must measure somewhere in between 0.3 V and also 4.2 V, which may vary, relying on the valve’s yes, really position. You deserve to test voltage output of vacuum-operated valves by varying just how much vacuum you use with the hand pump.If you measure up 5 V ~ above E2, you many likely additionally measure 5 V top top EGLS, which means you have actually an open up circuit back to the ECM ~ above the E2 soil circuit. Skip to Circuit inspect to diagnose and repair.If you measure 5 V ~ above VC and also EGLS, but 0 V on E2, you may have actually an interior or external quick circuit. Disconnect the sensor and also check for resistance between VC and EGLS ~ above the sensor itself.If you present less 보다 100 Ω, then you have a brief circuited sensor. Replace it.If you show in between 100 Ω and also 5,500 Ω, friend may have actually a short circuit in the cable harness. Skip come Circuit check to verify and repair.If you measure up 0 V ~ above E2 and also over 4.5 V on EGLS, then you have actually a fault in the sensor itself. Replace the sensor.Circuit check – Disconnect the ECM and also EGR position sensor and also measure resistance on the 3 wires. Every wire, VC, EGLS, and also E2, must measure 0 Ω end to end. Additionally, there need to be no connection between any of the three wires or to ground. You should measure at least 10 kΩ in between VC, EGLS, E2, and also body ground. Repair as necessary.