DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency. Buick Century (China) (CNG) 1999

For 1990-2009 cars only

Makes 🢒 Buick 🢒 1999 🢒 Century (China) (CNG) 🢒 Engine 🢒 Engine Controls - 3.0L (L46) 🢒 DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency

Engine Controls Components
MAF and EVAP
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

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 2000 Hertz at idle to near 8,000 Hertz at maximum engine load. DTC P0102 will be set if the signal from the MAF sensor is below the possible range of a normally operating MAF sensor.

Conditions for Running the DTC

•	The engine is running.

•	Ignition Voltage greater than 8.0V.

•	Throttle angle below 50%.

Conditions for Setting the DTC

•	MAF signal frequency is below 1200 Hertz.

•	Above conditions present for over 0.5 seconds.

Action Taken When the DTC Sets

•	The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecuitive trip in which the diagnostic has been run and failed.

•	If equipped with traction control, the PCM will command the EBTCM via the serial data circuit to turn OFF traction control, and the EBTCM will illuminate the TRACTION OFF lamp.

•	The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

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 the scan tool.

Diagnostic Aids

Check for the following conditions:

•	Poor connection at 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 fault.

•	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 4-6 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 DTC P0102 cannot be duplicated, the information included in the Fail Records data can be useful in determining vehicle mileage since the DTC was last set.

Test Description

The numbers below refer to the step numbers on the Diagnostic Table:

This step verifies that the problem is present at idle.

A voltage reading of less than 4 or over 6 volts at the MAF sensor signal circuit indicates a fault in the wiring or a poor connection.

Verifies that ignition feed voltage and a good ground are available at the MAF sensor.

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.

Step

Action

Value(s)

Yes

Was the Powertrain OBD System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Start the engine.
With the engine idling, monitor MAF FREQUENCY display on the scan tool Eng. 1 data list.

Is the MAF FREQUENCY below the specified value?

1200 Hz (1.2 kHz)

Go to Step 4

Go to Step 3

Turn the ignition on, and leave the engine off.
Review and record scan tool Fail Records data
Operate vehicle within Fail Records conditions as noted.
Using a scan tool, monitor Specific DTC info for DTC P0102.

Does scan tool indicate DTC P0102 failed this ignition?

Go to Step 4

Go to Diagnostic Aids

Check for the following conditions:

•	Objects blocking the MAF sensor inlet screen.

•	Intake manifold vacuum leaks.

•	Vacuum leaks at throttle body.

•	Vacuum leaks at EGR valve flange and pipes.

•	Crankcase ventilation valve faulty, missing, or incorrectly installed.

If a problem is found, repair as necessary.

Was a problem found?

Go to Step 14

Go to Step 5

Turn the ignition off.
Disconnect the MAF sensor connector.
Turn the ignition on, and leave the engine off.
Using a J 39200 DMM, measure voltage between the MAF signal circuit and battery ground.

Is the voltage near the specified value?

5.0V

Go to Step 6

Go to Step 9

Connect a J 35616-200 test light between the MAF sensor ignition feed and ground circuits at the MAF sensor harness connector.

Is the J 35616-200 test light on?

Go to Step 8

Go to Step 7

Connect a J 35616-200 test light between MAF sensor ignition feed circuit and battery ground

Is the J 35616-200 test light on?

Go to Step 10

Go to Step 11

Check for a poor connection at the MAF sensor.
If a poor connection is found, replace faulty terminals. Refer to Testing for Continuity , Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals and Connector Repairs .

Was a poor connection found?

Go to Step 14

Go to Step 12

Check the MAF signal circuit between the PCM and the MAF sensor for an open, short to ground, short to the MAF ground circuit, or short to voltage.
If the MAF signal circuit is open or shorted, repair it as necessary. Refer to Wiring Repairs .

Was the MAF signal circuit open or shorted?

Go to Step 14

Go to Step 13

Locate and repair the open in the ground circuit to the MAF sensor. Refer to Wiring Repairs .

Is the action complete?

Go to Step 14

Locate and repair the open in the ignition feed circuit to the MAF sensor. Refer to Wiring Repairs .

Is the action complete?

Go to Step 14

Replace the MAF sensor.

Is the action complete?

Go to Step 14