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 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.
^ The TP angle is less than 50 percent.
^ The system voltage is between 9 and 18 volts.

CONDITIONS FOR SETTING THE DTC
^ MAF signal frequency is less than 1,200 Hertz.
^ The above conditions present for more than 0.5 seconds + 400 3X reference periods (133 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 set during deceleration. Check 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. Check 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 2.27 g/sec.
7. If the minimum air rate is less than specifications, clean or replace the throttle body as necessary.

Check for the following conditions:
^ Poor connection at the PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
^ 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.
^ Damaged harness. Inspect the wiring harness for damage.
^ If the harness appears to be OK, observe the scan tool while moving connectors and wiring harnesses related to the MAF sensor. A change in the display will indicate the location of the malfunction.
^ 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 greater at the time of the 1-2 shift. If not, check for a restriction.

If the DTC cannot be duplicated and is determined to be intermittent, reviewing the Fail Records can be useful in determining when the DTC was last set. Also refer to Testing for Intermittent and Poor Connections in Diagrams.

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. 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.