Also the code shows a leak in the system - 2004 Chevrolet TrailBlazer

code p 442 refers to evaporative emission (EVAP) system---small leak detected
it also refers to large leak detected --fuel cap off/loose === causes hose/connection,-- intake leak--EVAP canister---EVAP canister purge valve --mechanical fault --- EVAP pressure sensor

Unfortunately the P0440 code could be a comdination of about 4 different possibilities within the EVAP System:

1. Fuel Cap loose or Not holding proper pressure causeing a leak in the EVAP System
2. EVAP Canister Purge Volume Control Valve
3. EVAP Canister Purge Control Valve
4. EVAP Canister Vent Control Valve

The Vent Control Valves are common for going bad and causing leaks in the EVAP System.

Now, the P0600 Code - ECM recieving incorrect voltage from A/T control Unit Continuously.

Unfortunately, my suggestion to you would be to take the vehicle to your local Nissan Dealer where they have the appropriate scan tools to monitor the EVAP System and the Transmission control System.

Hope this helps...

It would help if you could get the car scanned with vag-com, it will show the full fault code.

P0171/ Fuel Trim; Bank 1: System Too Lean
Possible Causes

* Mass Air Flow Sensor defective

Possible Solutions

* Check Mass Air Flow Sensor
* Check Fuel Pressure Regulation
* Check Fuel Pump
* Check Injectors
* Check Intake System for Leaks
* Check Exhaust System for Leaks
* Check Secondary Air System for Leaks
* Check Vacuum Pipes for Leaks

P0442 (M)
Evaporative Emission Control System Leak Detected (medium leak)
A 0.040 leak has been detected in the evaporative system. (A faulty gas cap may cause this code). Also see TSB 25-001-02A. Note: The respective Powertrain Diagnostic Procedures Manual will direct the technician to determine if the vehicle evaporative system has an external system leak. Examples of some external system leaks are: a loose gas cap, a disconnected evaporative system hose, or a loose hose connection. Remember that the evaporative system may also have an internal system leak. This internal leak may be caused by an intermittent or permanently stuck open Duty Cycle Purge (DCP) valve. This leak source is considered to be internal because any escaping emissions enter into the engine system and not directly into the atmosphere, unlike an external leak. An internal leak may cause one of the above DTC?s. Possible causes of a stuck open (intermittent or permanent) DCP valve are: 1. Corrosion due to system moisture or possible water intrusion into the system

P0442 Means you have a small leak in your EVAP system. P0455 is a large leak.
The EVAP system prevents gas vapors from entering the air .
This code can be set by a leak in the lines or a clogged charcoal canister.
Most common reason is If you did not put your gas cap on all the way.
Hope this helps
Leave feedback please
thank you FixYa

idle controll system idle to high is the code description

That last time I fixed this code it ended up being a leaking EVAP hose on top of the fuel tank. I had to drop the tank and put new sealant on the hoses to stop the leak.

Evaporative Emissions System - Small leak detected

Usually this P0456 code is caused by an incorrect or faulty gas cap. Filling the fuel tank with the engine running could conceivably cause this code as well or if the cap wasn't properly tightened.

Any of the following could also be the cause:

• A small leak in any of the EVAP hoses or fuel tank hoses
• A small leak in the purge valve or vent valve
• The EVAP Canister may be leaking

Solutions...
First, using a scan tool activate the vent solenoid, sealing the system. Then monitor the fuel tank pressure (FTP) sensor. If the system is sealing properly, the number will stay consistent. If is isn't, the pressure sensor will show that as well. If the system slowly leaks, use a smoke machine and watch for smoke exiting the system at any EVAP component. Any where there is smoke exiting the system, that is the faulty component. Do not pressurize the EVAP system with air pressure. Doing so can damage the purge and vent solenoids in the system.

Is this on the 99 323i that shows with your post?

The P0442 is indicating a leak in the fuel tank vent system. As a first step, double check that the gas cap is secured properly and that the seal is in good shape. Often this code can be generated by a loose or leaking gas cap ..... or ..... running the engine with the gas cap removed.

Clear the fault code (using the fault code tool) and see if the code returns (check engine light comes back on). If the light comes back on, check the fault codes and if it is the same code, you do indeed have a leak. The only way to find the leak (other than a quick visual inspection of the system, which may or may not show an obvious leakage point), is to pressureize the system and inject a special smoke which will leak out at any leakage points. The smoke machine is a special tool.

first check out for o2 sensor if its faulty this can show up.but if its proper.Evaporative emission control system leak very small 171 System too lean (bank 1) 174 System too lean (bank 2)