P0102

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 engine control module (ECM) uses the MAF sensor voltage signal to provide the correct fuel delivery for a reduction in emissions. The ECM uses the MAF sensor signal to control fuel delivery until a calibrated amount of engine air flow is attained. The MAF sensor has an ignition 1 voltage circuit, a signal circuit and a low reference circuit. The MAF sensor produces an output voltage based on the inlet air flow through the air induction system. This output voltage will display on the scan tool as a grams per second (g/s) value. If the ECM detects that the actual MAF sensor voltage signal is less than the possible range of a normally operating sensor DTC P0102 sets.

CONDITIONS FOR RUNNING THE DTC
- The engine is running for more than 2 seconds.
- The engine speed is more than 500 RPM.
- The ignition 1 signal is more than 9 volts.
- The above conditions are present for more than 2 seconds.

CONDITIONS FOR SETTING THE DTC
- The ECM detects that the MAF sensor signal is less than 0.5 volt. This equals a MAF value of less than 16 g/s.
- The condition is met for more than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
Inspect for the following conditions:
- Any unmetered air.Any unmetered air that enters the engine downstream of the MAF sensor may cause this DTC to set.
- A sluggish or unresponsive MAF sensor.A short between the signal circuit of the MAF sensor and the signal circuit of the intake air temperature (IAT) sensor. This will cause the MAF sensor to have a very limited output voltage range.
- Any debris that may be blocking the sensing elements of the MAF sensor
- Any water in the air induction system
- The MAF display should increase from 42-50 g/s at idle to 420 g/s or more at the 2-3 shift during a wide-open throttle (WOT) acceleration. If not, inspect for a restriction in the induction system or the exhaust system.
- If the condition is intermittent, refer to Intermittent Conditions. Diagnostic Strategies

TEST DESCRIPTION

Steps 1-4:

Step 5:

Steps 6-9:

Steps 10-13:

Steps 14-20:

The number below refers to the step number on the diagnostic table.
11. A short to another ECM controlled circuit may not be present when the ECM is disconnected as part of the previous test. A short across two ECM circuits can cause this DTC to set.