2001 Chevrolet/Geo Camaro  

DTC P0102

Circuit Description

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load situation. The MAF sensor has an ignition 1 voltage circuit, a ground circuit and a signal circuit. The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency will vary within a range of around 2,000  Hertz at idle to about 10,000  Hertz at maximum engine load. DTC  P0102 will set if the PCM detects a frequency signal lower than the possible range of a normally operating MAF sensor.

Conditions for Running the DTC
Conditions for Setting the DTC
Action Taken When the DTC Sets
Conditions for Clearing the MIL/DTC
Diagnostic Aids

Inspect for the following conditions:

A wide open throttle (WOT) acceleration from a stop should cause the mass air flow display on a scan tool to increase from about 4-7  g/s at idle to about 130 g/s or more at the time of the 1-2 shift. If not, inspect for a restriction.

If you suspect the vehicle condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.

If the condition is intermittent refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies the signal circuit from the MAF sensor electrical connector to the PCM. A voltage reading of less than 4 volts or greater than 6 volts indicates a malfunction in the wiring or a poor connection.

  2. This step tests the signal circuit of the MAF sensor for a short to another 5-volt reference circuit.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Install a scan tool.
  2. Start the engine.
  3. With a scan tool observe the frequency parameter of the MAF sensor .

Does the scan tool indicate that the frequency is less than the specified value?

800  Hz

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30  seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC or, within the parameters observed in the Freeze Frame/Failure Records.

Does the DTC fail this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

Inspect the fuse in the ignition 1 voltage circuit of the MAF sensor. Refer to Power Distribution Schematics in Wiring Systems.

Is the fuse open?

--

Go to Step 14

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the harness connector of the MAF sensor. Refer to Mass Air Flow (MAF) Sensor Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the signal circuit of the MAF sensor to a good ground. Refer to Circuit Testing in Wiring Systems.

Does the voltage measure near the specified value?

5 V

Go to Step 6

Go to Step 8

6
  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the MAF sensor and a good ground. Refer to Circuit Testing in Wiring Systems.
  3. Start the engine.

Do any additional DTCs set?

--

Go to Step 16

Go to Step 7

7
  1. Turn OFF the ignition.
  2. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and the ground circuit of the MAF sensor. Refer to Circuit Testing in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

--

Go to Step 18

Go to Step  11

8

Does the voltage measure less than the specified value?

4.5 V

Go to Step 10

Go to Step 9

9
  1. Turn OFF the ignition.

    important

    Disconnecting the PCM connectors may eliminate the short to voltage if the signal circuit is shorted to another PCM circuit.

  2. Disconnect the PCM. Refer to Powertrain Control Module (PCM) Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the signal circuit of the MAF sensor to a good ground. Refer to Circuit Testing in Wiring Systems.

Does the voltage measure near the specified value?

0 V

Go to Step 12

Go to Step  15

10
  1. Turn OFF the ignition.
  2. Disconnect the PCM. Refer to Powertrain Control Module (PCM) Replacement .
  3. Test the signal circuit between the PCM and the MAF sensor for the following conditions:
    • A high resistance or an open
    • A short to ground
    • A short to the ground circuit of the MAF sensor--Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step  12

11

Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and a good ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step  13

Go to Step  14

12

Test for continuity at the harness connector of the PCM from the signal circuit of the MAF sensor to all other circuits at both PCM connectors. Refer to Circuit Testing in Wiring Systems.

Does the DMM indicate continuity between any other circuit?

--

Go to Step  17

Go to Step  19

13

Repair the high resistance or an open in the ground circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step  22

--

14

    important

    The ignition 1  voltage circuit of the MAF sensor is spliced to other components on the vehicle. Refer to Power Distribution Schematics in Wiring Systems.

  1. Repair the short to ground or an open in the ignition 1  voltage circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the fuse if necessary.

Did you complete the repair?

--

Go to Step  22

Go to Step  20

15

Repair the short to voltage in the signal circuit of the MAF sensor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step  22

--

16

Repair the short between the signal circuit of the MAF sensor and the circuit for which the DTC set. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step  22

--

17

Repair the circuits that are shorted together. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step  22

--

18

Inspect for poor connections at the harness connector of the MAF sensor. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step  22

Go to Step  20

19

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent and Poor Connections , and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step  22

Go to Step  21

20

Replace the MAF sensor. Refer to Mass Air Flow (MAF) Sensor Replacement .

Did you complete the replacement?

--

Go to Step  22

--

21

Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .

Did you complete the replacement?

--

Go to Step  22

--

22
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30  seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step  23

Go to Step 2

23

With a scan tool, observe the stored information in Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK