So i got my code checked and its P0405 says low circuit, brand egr valve brand new fuel regulator, i noticed some shrink wrap on the harness like it had been tampered with so im thinking its a wiring

CEL on, P0405
that dont effect engine running, nor can many more DTC>
DTC = errors.
405 is EGR.
if the egr is stuck open the engine stall.s
if it is not working dead, only the TEST FAILS.
true back to 1987 cars. (about)
its federal mandated test in the USA from then.

EGR is kinda simple on newer cars.
its a valve. and some have read back. telling the brain
hey, i didnt move.
id clean it first.
.
- EGR volume control solenoid valve
- EGR volume control solenoid valve harness is open or shorted
- EGR volume control solenoid valve circuit poor electrical connection
- EGR temperature sensor and circuit

code p0403 refers to EGR --circuit malfunction===causes ---wiring--EGR solenoid---ECM
code p0405 refers to EGR valve position sensor A --low input===causes ---wiring ---short to ground---EGRF valve position sensor--- ECM.
By only changing the EGR valve you have not fixed the problems that cause the valve not to work.

EGR Valve issue

onestly, your best bet is to replace the valve if nor mistaking it comes with the sensor, make sure pasages are not blocked, start the car with out the egr it will go up and down rpm and will be noisy if egr pipe is not blocked

P0405 means Exhaust Gas Recirculation Sensor A Circuit Low. It may caused by Short to ground in EGR signal or Reference circuits or voltage in EGR ground or signal circuits;Bad EGR valve; or Bad PCM wiring issues due to chafing or loose terminals.
P0300 is Random/Multiple Cylinder Misfire Detected. It may be something wrong with spark plugs or wires,coil,oxygen sensor,fuel injector,etc.
As for P2670, it seems for the Actuator Supply Voltage "B" Circuit Low.

greetings

DTC P0405 - Exhaust Gas Recirculation Sensor A Circuit Low

There are different designs of EGR (Exhaust Gas Recirculation) systems, but they all operate in a similar way. The EGR valve is a PCM (Powertrain Control Module) controlled valve that allows measured amounts of exhaust gasses to pass back into the cylinders to be burned with the air/fuel mixture. Since exhaust gas is an inert gas that displaces oxygen, injecting it back into the cylinder can lower combustion temperatures which helps to improve NOx (oxides of nitrogen) emissions. EGR isn't needed on cold startup or at idle. EGR is commanded on under certain conditions like startup or at idle. EGR is commanded on under certain conditions like partial throttle or decel depending on engine temperature and load, etc. Exhaust gasses are supplied to the EGR valve from an exhaust pipe or the EGR valve may be mounted directly in the exhaust manifold. When needed, the valve is commanded "on" allowing the gasses to pass into the cylinders. Some systems divert exhaust gasses directly into the cylinders while others simply inject it into the intake manifold where it is then pulled into the cylinders. while others simply inject it into the intake manifold where it is then pulled into the cylinders.

Some EGR systems are quite simple while others are a little more complicated. Electrically controlled EGR valves are directly controlled by the PCM. A wiring harness plugs into the valve itself and is commanded by the PCM as it sees the need. These can be 4 or 5 wire. Usually 1 or 2 grounds 12 volt ignition feed, a 5 volt reference circuit, and a feedback circuit. Other systems are vacuum controlled. These are quite simple. The PCM controls a vacuum solenoid which when activated, allows vacuum to travel to the EGR valve and open it. There should also be an electrical connector on this type of EGR valve for the feedback circuit. The EGR system feedback circuit allows the PCM to see if the EGR valve pintle is actually moving as it should. If the feedback circuit detects that the voltage is unusually low, or it's position is lower than it's commanded to be, P0405 may set.


Symptoms of a P0405 DTC may include:
MIL (Malfunction Indicator Lamp) illumination


Potential causes of a P0405 code include:
Short to ground in EGR signal or Reference circuits
Short to voltage in EGR ground or signal circuits
Bad EGR valve
Bad PCM wiring issues due to chafing or loose terminals


Possible Solutions:
If you have access to a scan tool you can command the EGR valve on. If it responds and the feedback indicates the valve is moving properly then the problem may be intermittent. Sometimes in cold weather, moisture can freeze in the valve causing it to stick. After the vehicle warms up the problem may disappear. Carbon or other debris can lodge in a valve causing it to stick also

If the EGR valve doesn't respond to your commands with the scan tool, disconnect the EGR harness connector. Turn the key to on position, engine off (KOEO). Using a voltmeter, check for 5 volts on the reference wire to the EGR valve. If there is no 5 volts, is there any voltage at all? If there is 12 volts, then repair short to voltage in the 5 volt reference circuit. If there is no voltage connect a test light to battery voltage and probe the 5 volt reference wire. If the test light illuminates, the 5 volt reference circuit is shorted to ground. Repair as necessary. If the test light doesn't illuminate check for an open in the 5 volt reference circuit. Repair as necessary

If there is no apparent problem and there is no 5 volt reference, PCM may be at fault, however other codes will likely be present. If 5 volts are present on the reference circuit, jumper the 5 volts to the EGR signal circuit. Now the EGR position on the scan tool should read 100 percent. If it doesn't connect test light to battery voltage and probe the EGR signal circuit. If it illuminates, then the signal circuit is shorted to ground. Repair as necessary. If the light doesn't illuminate, check for an open on the EGR signal circuit. Repair as necessary.

If, after jumpering the 5 volt reference circuit to the EGR signal circuit the scan tool EGR position reads 100 percent, then check for poor terminal tension at the EGR valve connector. If the wiring is okay, replace the EGR valve.

Hope this helps.

The DTC P0405 is for (Exhaust Gas Recirculation Sensor Circuit "A" Low)

DTC P0406 is for (Exhaust Gas Recirculation Sensor Circuit "A" High)

This would indicate a problem with the EGR valve sensor, or the EGR valve itself is malfunctioning.

404 is exhaust gas recirculation circuit, and 405 is exhaust gas recirculation sensor circuit low. EGR sensor or ground?

Exhaust Gas Recirculation System Is the main problem here. the other code P0118 may be a bad temprature sensor or your thermostate needs to be changed. Last it could be a weak water pump. 

So what is an EGR system and how does it work? EGR stands for Exhaust Gas Recirculation, and as its name implies, this system allows exhaust gasses from your car to be re-circulated into the engine, helping to reduce emissions. These systems are mostly comprised of the EGR valve, a DPFE (Delta Pressure Feedback EGR) sensor, hoses, a vacuum regulator, some vacuum lines, wiring, the computer and the exhaust tube leading to the valve itself. 
The car's wiring can be tested in the normal fashion by looking for broken and lose wire, and all vacuum lines can be checked easily for cracks, leaks and correct routing.
The last thing i would then check is the the EGR valve, EGR vacuum regulator and DPFE sensor (or similar flow sensor).
I hope this helps and good luck