Am replacing my Engine Air Filter and am having trouble disconnecting the air flow sensor electrical connector. It is a tight connection. Is there a trick to disconnecting it? i don't want to break an

Hi Chris.

p0304 = Number 4 Cylinder Misfire Detected

Faulty spark plug 4
Clogged or faulty fuel injector 4
Faulty ignition coil 4
Fuel injector 4 harness is open or shorted
Fuel injector 4 circuit poor electrical connection
Ignition coil 4 harness is open or shorted
Ignition coil 4 circuit poor electrical connection
Insufficient cylinder 4 compression
Incorrect fuel pressure
Intake air leak

The P0304 code means that the cylinder 4 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 4.


p0102 = Mass or Volume Air Flow Circuit Low Input

Faulty mass air flow sensor
Intake air leaks
Dirty mass air flow sensor
Dirty mass air filter
Mass air flow sensor harness is open or shorted
Mass air flow sensor circuit poor electrical connection

Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner.
Reset code and drive vehicle.
If the code comes back, it may be necessary to replaced the mass air flow sensor.


p0154 = O2 Sensor Circuit No Activity Detected Sensor 1 Bank 2

Faulty Front Heated Oxygen Sensor Bank 2
Front Heated Oxygen Sensor Bank 2 harness is open or shorted
Front Heated Oxygen Sensor Bank 2 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks

Replacing the Front Heated Oxygen Sensor Bank 2 usually takes care of the problem.


p0113 = Intake Air Temperature Sensor Circuit High

Faulty Intake Air Temperature (IAT) sensor
Dirty air filter
Intake Air Temperature (IAT) sensor harness is open or shorted
Intake Air Temperature (IAT) sensor circuit poor electrical connection

The Intake Air Temperature (IAT) sensor is built into mass air flow sensor or in some vehicles mounted to the air filter duct housing. The sensor detects intake air temperature and transmits a signal to the Engine Control Module (ECM).The temperature sensing unit uses a thermistor which is sensitive to the change in temperature. Electrical resistance of the thermistor decreases in response to the temperature rise. The Intake Air Temperature signal is used as an input for various systems in the vehicle.



Hope this helps
FYT

http://www.autocodes.com/make/nissan

P0102 Chevrolet - Mass or Volume Air Flow Circuit Low Input

Read more: http://engine-codes.com/p0102_chevrolet.html#ixzz38p5k1ZD8

Possible causes - Faulty mass air flow sensor
- Intake air leaks
- Dirty mass air flow sensor
- Dirty mass air filter
- Mass air flow sensor harness is open or shorted
- Mass air flow sensor circuit poor electrical connection

Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.


Read more: http://engine-codes.com/p0102_chevrolet.html#ixzz38p5tpWZk

P0102 - Mass Air Flow Sensor Circuit Malfunction

The mass air flow or MAF sensor is placed in the intake air duct between the air filter and the engine intake manifold. The MAF sensor measures the amount of intake air flow. The MAF sensor converts the air flow measurement into a voltage or frequency signal, with the voltage or frequency changing proportionally to the amount of air flow. The air flow sensor signal is monitored by the engine computer (ECM). The engine computer (ECM) uses the mass air flow signal to know the engine load and to calculate the proper amount of fuel injected. If the signal from the mass air flow sensor is out of expected range, the ECM detects a fault and sets the code P0100. For example, the mass air flow sensor signal could be higher than expected when the engine is not running or lower than expected with the engine running. A car with the code P0100 may have some driveability issues, such as stalling, lack of power, surging, hesitation, etc. In some cars, the code P0100 can cause the fail-safe mode where the engine speed would be limited to 2,500 - 3,000 rpm.
If there are other trouble codes present, they might need to be looked at first. Checking the freeze frame may help, as it may contain some important information. The freeze frame is a snapshot of the engine parameters at the moment when the fault was detected. The freeze-frame may show whether the vehicle was running or stopped, whether the air-fuel ratio was lean or rich, was the engine was cold or warmed up at the time of the malfunction. Read more about the freeze frame.

Read more about mass air flow sensor.

What could cause the code P0100:
- faulty or contaminated mass air flow sensor
- open or short in the mass air flow sensor electrical circuit
- open or short in the sensor power or ground circuit

- other electrical problem with the MAF sensor wiring, (corroded wires, bent terminals, bad ground connection, burned fuse, etc.
- vacuum leaks
- restricted air flow at or before the air filter
- wrong air flow sensor installed
- problem with ECM

P0102 - Mass Air Flow Sensor Circuit Low

The mass air flow or MAF sensor measures the amount of air entering the engine. The engine computer (ECM) uses the mass air flow signal to calculate the amount of fuel injected (read more how the MAF sensor works below). The code P0102 is set when the signal from the mass air flow sensor is lower than expected. Often a car may exhibit some driveability symptoms, such as lack of power, surging, hesitation on acceleration, hard starting, pinging (detonation), or rough idle when started cold. Often the codes P0171 or P0174 could also be stored along with the code P0102, as the incorrect air flow signal can cause the engine to run lean. The codes P0171 and P0174 indicate a lean condition. Checking the freeze frame might help in the diagnostic process. The freeze frame is stored in the ECM along with the trouble code. The freeze frame contains some recorded parameters (e.g. vehicle speed, engine temperature, fuel trim) at the moment when the fault was detected. The freeze frame can also be accessed with a scan tool.

What could cause the code P0102
- faulty or contaminated mass airflow sensor
- debris blocking the air flow at the mass air flow sensor
- unmetered air leaking past the MAF sensor (vacuum leaks)
- PCV system vacuum leaks
- restricted or collapsed intake air duct
- dirty or restricted air filter
- restricted air screen before the air filter
- improper application of aftermarket components (e.g. cold intake, modified air filter, etc.)
- wrong air flow sensor installed
- electrical problem with the MAF sensor wiring, connector, power supply or ground.
- problem with ECM
- in some cases other issues with the fuel injection system like a clogged catalytic converter or a faulty manifold absolute pressure sensor (MAP) can also cause the code P0102.

Solution for MAF repair

P0103 HYUNDAI - Mass or Volume Air Flow Circuit High InputPossible causes- Dirty mass air flow sensor
- Dirty mass air filter
- Mass air flow sensor harness is open or shorted
- Mass air flow sensor electrical circuit poor connection
- Intake air leaks
- Faulty mass air flow sensor
Tech notesBefore replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.
P0112 HYUNDAI - Intake Air Temperature Sensor 1 Circuit Low InputPossible causes- Dirty air filter
- Intake air temperature (IAT) sensor harness is open or shorted
- Intake air temperature (IAT) sensor electrical circuit poor connection
- Faulty intake air temperature sensor
When is the code detected?An excessively low voltage from the sensor is sent to ECM.

Usually can't tell if it's bad by looking. Recommend you test the sensor using a multimeter. Instructions are pasted below.

OPERATION
See Figure 1
The Mass Air Flow (MAF) sensor
measures the amount of air which passes through it. The ECM uses this information to determine the operating condition of the engine, to control fuel delivery. A large quantity of air indicates acceleration, while a small quantity indicates deceleration or idle.
This sensor produces a frequency o
utput between 32 and 150 hertz. A scan t
ool will display air flow in terms of grams of air per second (gps), with a range from 3gps to 150 gps.

Fig. Fig. 1: Location of the MAF sensor on a 1991 vehicle
TESTINGSee Figures 2, 3, 4, 5 and 6

1. Visually check the connector, making sure it is connected properly and all of the terminals are straight, tight and free of corrosion.
2. With the engine running, lightly tap on the MAF sensor and wiggle the wires at the connector, while watching for a change in idle speed. A common problem is MAF sensor wire damage.

Fig. Fig. 2: MAF sensor circuit

1. Backprobe using a DVOM set to the Hertz scale between terminals A and B. Simulate operating conditions by blowing air across the sensor. There should be a frequency swing from the air crossing the wire in the sensor. A normal flow signal will be close to 1200 hertz. If the frequency is not shown, or not proportionate to the air blown across the sensor, the sensor is faulty.

Fig. Fig. 3: Attach a DVOM to the MAF sensor electrical connector's top and middle terminals and check for a 5 volt reference signal

Fig. Fig. 4: Check the middle and bottom connector terminals for 12 volts

Fig. Fig. 5: Connect a DVOM to the MAF sensor and check the air flow's corresponding voltage reading (0.144 volts in this case) ...

Fig. Fig. 6: ... then use a hair dryer to blow air into the sensor and note the fluctuation in the reading

1. Check for battery positive (B+) volt age on terminal C and ground on terminal B. If voltage or ground are not present, check the circuits back to the PCM for continuity.
2. If you receive the proper amount of voltage at the electrical connector and still have a driveability problem, replace the MAF sensor.
3. If the sensor and circuits are functional, the PCM may be faulty.

REMOVAL & INSTALLATION On 1987-91 vehicles, the MAF sensor is the electronics portion (black) and the aluminum housing to which it is attached. On later models, the MAF sensor just consists of the electronic portion, mounted to the throttle body.
1992-99 Vehicles
See Figures 11 and 12

1. Disconnect the negative battery cable.
2. Unplug the MAF sensor electrical connector.
3. Remove the 3 retaining screws, then remove the MAF sensor from the throttle body.

Fig. Fig. 11: On 1992-95 vehicles, the MAF sensor is mounted to the side of the throttle body

Fig. Fig. 12: The MAF sensor is attached to the top of the throttle body on 1996-99 vehicles
To install:

1. Carefully position the MAF sensor to the throttle body, then install the retaining screws.
2. Attach the sensor electrical connector.
3. Connect the negative battery cable.

The fuel filter is located on the right side of the engine bay just in front of the power steering fluid reservoir. Remove the "snorkel tube" from the front of the air cleaner housing. Using the 3/8" ratchet and 10mm socket remove the support bolt for the left half of the air cleaner housing.Disconnect the electrical connector to the mass air flow sensor by turning the plastic locking ring and then gently pulling the connector off of the mass air flow sensor.There is a sealing gasket between the air flow sensor and the air cleaner housing. Theoretically, you should be able to use a 17mm and 19mm flare wrench on the connection towards the front of the car.there is a black plastic offset washer between the fuel support bracket and the side of the engine bay. Don't forget to put this back in place when putting everything back together. Here you can find more quality parts http://www.buyautoparts.com/auto-parts/fuel_filter.htm

REMOVAL & INSTALLATION

Fig. Remove the starter electrical connections, noting their locations

Fig. Location of the two starter retaining bolts

1. Disconnect the negative battery cable.
2. Detach the air-flow sensor assembly connector and remove the breather hose.
3. Remove the resonator retaining nuts and remove the air intake hose and resonator assembly as required.

NOTE Use care when removing the air cleaner cover because the air-flow sensor is attached and is a sensitive component.

1. If equipped with Active-ECS suspension, remove the air compressor as follows:

1. Detach the two electrical connectors, from the compressor.
2. Disconnect the air line at the compressor.
3. Remove the three mounting bolts, securing the compressor to the chassis.

1. Raise the vehicle and support safely.
2. Remove the engine undercover.
3. Remove the heat shield from beneath the intake manifold on the 1.5L engine.
4. If necessary, detach the speedometer cable connector at the transaxle end.
5. Detach the starter motor electrical connections.
6. Remove the starter motor mounting bolts and remove the starter.
7. The installation is the reverse of the removal procedure. Tighten the starter mounting bolts to 22 ft. lbs. (31 Nm).
8. Connect the negative battery cable and check the starter for proper operation.

3.8L Engine To Remove:
MAF Location

1. Disconnect the battery ground cable.
2. Remove the fuel injector cover.
3. Disconnect the mass air flow (MAF) sensor electrical connector.
4. Remove the MAF sensor mounting screws.
5. Remove the MAF sensor from the throttle body.

To Install:

1. Position the MAF sensor on the throttle body.
2. Install the MAF sensor mounting screws. Tighten the mounting screws to 27 in lb (3 Nm).
3. Connect the mass air flow (MAF) sensor electrical connector.
4. Install the fuel injector cover.
5. Connect the battery ground cable.

REMOVE ENGINE COVER DISCONNECT MASS AIR FLOW SENSOR CONNECTOR.LOOSEN AIRDUCT FLOW TUBE SCREWS THEN REMOVE AIR FILTER COVER HOUSING BOLTS THEN RAISE AIR FILTER COVER UP SLIGHTLY ENOUGH SLIDE IT AWAY FROM AIRFLOW DUCT.THEN REMOVE COVER REPLACE AIR FILTER THEN PUT EVERYTHING BACK UP VISA VERSA DONT FORGET TO TIGHTEN SCREWS TO AIRFLOW DUCT TUBE ONCE AIR FILTER HOUSING BACK IN PLACE.

Removal and Installation To Remove:

1. Remove or disconnect the following:
   • Mass air flow sensor electrical connector
   • Tube clamp at the electronic throttle control actuator
   • Air cleaner to electronic throttle control actuator tube, upper air cleaner case
   • Mass air flow sensor from the cleaner case.

To Install:

1. Install or connect the following:
   • Mass air flow sensor to the cleaner case
   • Air cleaner to electronic throttle control actuator tube
   • Tube clamp at the electronic throttle control actuator
   • Mass air flow sensor electrical connector