Fault codes, p0102,p0122,po507

SOURCE: 1999 passat tdi power fault

Air mass sensor, almost never shows codes but always makes the vehicle loose power !! cheaper from vw than pattern and more reliable

SOURCE: after changing fuel pump 2 days ago on my 97

You can test the MAF before replacing. It may be a problem with the circuit itself or just a fluke from another problem that is connected to this sensor.

There are two basic types of mass airflow sensors: hot wire and hot film. In the first type, a very thin wire (about 0.2 mm thick) is used as the heated element.
Components of a hot wire-type mass airflow sensor. Courtesy of Ford Motor Company. The element temperature is set at 100° to 200°C above incoming air temperature. Each time the ignition switch is turned to the off position, the wire is heated to approximately 1,000°C for 1 second to burn off any accumulated dust and contaminants.
The second type uses a nickel foil sensor, which is kept 75°C above ambient air temperatures. It does not require a burn-off period and therefore is potentially longer lasting than the hot wire type.
A faulty MAF will cause driveability problems resulting from incorrect ignition timing and improper air/fuel ratios.
Vane-type MAF Sensors
A vane-type MAF sensor is found on many import and domestic vehicles with EFI. All intake air must flow through the sensor. Some MAF sensors are called volume air flow meters

• Begin checking a vane-type MAF sensor by checking the voltage supply wire and the ground wire to the MAF module before checking the sensor voltage signal.
• Always follow the recommended test procedure in the manufacturer's service manual and use the specifications supplied by the manufacturer.
• Typically, to test the sensor, a digital multimeter (DMM) is used and set on a DC voltage scale. The negative meter lead is connected to ground and the red lead to the MAF signal wire.

• Turn on the ignition switch and press the min/max button, if available, on the DMM.
• Slowly push the MAF vane from the closed to the wide-open position, and allow the vane to slowly return to the closed position.

• Observe the maximum and minimum voltage readings as the vane was moved.
• If the minimum voltage signal is zero, there may be an open circuit in the MAF sensor variable resistor.
• When the voltage signal is not within the manufacturer's specifications, replace the sensor.

• Some vehicle manufacturers specify ohmmeter tests for the MAF sensor.
• With the MAF sensor removed, connect the ohmmeter across the sensor's output and input terminals.

• The resistance at these terminals is normally 200 to 600 ohms.
• Connect the ohmmeter leads to the specified MAF sensor terminals, and move the vane from the fully closed to the fully open position.
• With each specified meter connection and vane position, the ohmmeter should indicate the specified resistance.

• When the ohmmeter leads are connected to the sensor's input and output terminals, the ohmmeter reading should increase smoothly as the sensor vane is opened and closed.
• To check a vane-type MAF with a lab scope, connect the positive lead to the output signal terminal and the negative scope lead to a good ground.
• This type MAF should display an analog voltage signal when the engine is accelerated. A defective MAF will have sudden and erratic voltage changes.

• To check the MAF sensor's voltage signal and frequency, connect a voltmeter across the MAF voltage signal wire and ground wire.
• Start the engine and observe the voltmeter reading.
• On some MAF sensors, this reading should be 2.5 volts.
• Lightly tap the MAF sensor housing with a screwdriver handle and watch the voltmeter pointer.
• If the pointer fluctuates or the engine misfires, replace the MAF sensor.
• Some MAF sensors have experienced loose internal connections, which cause erratic voltage signals and engine misfiring and surging.
• Set the DMM so that it can read the frequency of DC voltage.
• With it still connected to the signal wire and ground, the meter should read about 30 Hz with the engine idling.
• Now, increase the engine speed, and record the meter reading at various speeds.
• Graph the frequency readings. The MAF sensor frequency should increase smoothly and gradually in relation to engine speed.
• If the MAF sensor frequency reading is erratic, replace the sensor.

• When a scanner is used to diagnose a General Motors' vehicle, one test mode displays grams per second from the MAF sensor. This mode provides an accurate test of the MAF sensor.
• The grams per second reading should be 4 to 7 with the engine idling.
• This reading should gradually increase as the engine speed increases.
• When the engine speed is constant, the grams-per-second reading should remain constant.
• If the grams-per-second reading is erratic at a constant engine speed or if this reading varies when the sensor is tapped lightly, the sensor is defective.
• A MAF sensor fault code may not be present with an erratic grams-per-second reading, but the erratic reading indicates a defective sensor.
• Frequency-varying types of MAF sensors can be tested with a lab scope.
• The waveform should appear as a series of square waves.

• When the engine speed and intake air flow increases, the frequency of the MAF sensor signals should increase smoothly and proportionately to the change in engine speed.
• If the MAF or connecting wires is defective, the trace will show an erratic change in frequency.

Clutch

• 870 Answers
• Posted on Dec 16, 2010

SOURCE: I have five fault codes

P0507, Idle Control System RPM Higher Than Expected
P0122,Generic TPS/Throttle position sensor A circuit low input
P0106, Manifold Absolute Pressure barometric Pressure Circuit Range/Performance problem
P0108, Manifold Absolute Pressure ( MAP) Sensor circuit high voltage.

Good luck