P0102

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

CIRCUIT DESCRIPTION
The Mass Air Flow (MAF) sensor measures the amount of air which passes through it into the engine during a given time. The Powertrain Control Module (PCM) uses the mass air flow information to monitor engine operating conditions for fuel delivery calculations. A large quantity of air entering the engine indicates an acceleration or high load situation, while a small quantity of air indicates deceleration or idle. The MAF sensor produces a frequency signal which can be monitored using a scan tool. The frequency will vary within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. If the signal frequency from the MAF sensor is lower than the possible range of a normally operating MAF sensor DTC P0102 will set.

CONDITIONS FOR RUNNING THE DTC
^ The engine is running.
^ TP angle is less than 50 percent.
^ System voltage is more than 8 volts.

CONDITIONS FOR SETTING THE DTC
^ MAF signal frequency is less than 1,200 Hertz.
^ The above condition is present for longer than 0.5 seconds + 100 3X reference periods, 33 crankshaft revolutions.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
^ The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
A low minimum air rate can cause DTC P0102 to be set during deceleration. Test the minimum air rate as follows:
1. Run the engine until fully warm, above 85°C (185°F).
2. Disconnect the IAC.
3. Install a J 37027-A IAC system monitor.

4. With the engine idling, command the IAC valve to the fully extended position, 0 counts.
5. With the IAC fully extended, observe the Mass Air Flow reading on the scan tool.
6. Inspect for conditions that can cause a low minimum air rate, including throttle bore and throttle plate coking if the Mass Air Flow reading is less than the following values:
^ 2.95 g/sec
7. If the minimum air rate is less than specifications, clean or replace the throttle body as necessary. Refer to Throttle Body Assembly Replacement.

Inspect for the following conditions:
^ Misrouted harness - Inspect the MAF sensor harness to ensure that it is not routed too close to high voltage wires such as spark plug leads.
^ Plugged intake air duct or filter element - A Wide Open Throttle acceleration from a stop should cause the Mass Air Flow displayed on a scan tool to increase from about 4-7 gm/s at idle to 100 gm/s or more at the time of the 1-2 shift. If not, inspect for a restriction.

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension.
^ Damaged harness-Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault.
^ PCM and engine grounds for clean and secure connections

If the DTC is determined to be intermiffent, reviewing the Failure Records can be useful in determining when the DTC was last set.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies that the problem is present at idle.
5. A voltage reading of less than 4 or over 6 volts at the MAF sensor signal circuit indicates a malfunction in the wiring or a poor connection.
6. This step verifies that ignition feed voltage and a good ground are available at the MAF sensor.
13. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.