DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency. GMC Truck Yukon

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1997 🢒 Yukon - 4WD 🢒 DTC 🢒 DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency

Engine Controls Components
DIESEL PCM, MAF, EGR, APP, WASTEGATE
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The Mass Air Flow (MAF) sensor measures the amount of air entering the engine during a given time. The PCM uses the mass air flow information to monitor EGR flow rates. A large quantity of air entering the engine indicates an acceleration, high load situation or no EGR flow, while a small quantity of air indicates deceleration, idle or full EGR situations.

The MAF sensor produces a frequency signal. DTC P0102 will be set if the signal from the MAF sensor does not match a predicted value based on, engine coolant temperature, APP angle and engine speed.

DTC P0102 will be set if the signal from the MAF sensor is below the possible range of a normally operating MAF sensor. This is a type B DTC.

Conditions for Setting the DTC

•	The engine is running.

•	Engine run time is greater than 2 seconds.

•	Ignition ON for 2 seconds

•	MAF sensor is less than 1280 Hz

Action Taken When the DTC Sets

•	The PCM will illuminate the Malfunction Indicator Lamp (MIL) on the second consecutive fault.

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

Conditions for Clearing the MIL/DTC

•	The PCM will turn the MIL OFF on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.

•	A history DTC P0102 will clear after 40 consecutive warm-up cycles have occurred without a fault.

•	DTC P0102 can be cleared by using the scan tool Clear Info function.

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.

•	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.

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.

The Adaptive Learn Matrix (ALM) is used to adjust the EGR vacuum control based on Mass Air Flow (MAF). The ALM may change as a result of back pressure increases over the life of the vehicle or other engine system variations. The ALM is made up of sixteen cells (numbered from zero to fifteen) in which each cell covers a range of engine speed (RPM) and load (mm3).

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table:

This step verifies that the problem is present at idle.

A voltage reading of less than 4 or over 6V 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. Refer to Powertrain Control Module Replacement/Programming .

Step

Action

Value(s)

Yes

Important: Before clearing DTC(s) use the scan tool to record Freeze Frame and Failure Records for reference, as data will be lost when the Clear Info function is used.

Was the Powertrain On-Board Diagnostic (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 the MAF display on the scan tool.

Is the MAF display below the specified value?

1280 Hz

Go to Step 4

Go to Step 3

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

Does scan tool indicate DTC P0102 failed this Ign?

Go to Step 4

Refer to Diagnostic Aids

Check for the following conditions:

•	Objects blocking the MAF sensor inlet.

•	Large intake manifold leaks

•	Large leaks at the EGR valve flange or tower gasket.

•	Large leaks downstream of the MAF sensor.

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, engine OFF.
Using a J 39200 , measure the voltage between the MAF signal circuit and ground.

Is the voltage near the specified value?

Go to Step 6

Go to Step 9

Connect a test light between the MAF sensor ignition feed and ground circuit at the MAF sensor harness connector.

Is the test light ON?

Go to Step 8

Go to Step 7

Connect a test light between MAF sensor ignition feed circuit and battery ground.

Is the 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, repair as necessary.

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 sensor ground circuit, or short to voltage.
If the MAF sensor signal circuit is open or shorted, repair as necessary.

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.

Is the action complete?

Go to Step 14

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

Is the action complete?

Go to Step 14

Replace the MAF sensor.

Is the action complete?

Go to Step 14