The mass air flow (MAF) sensor is an air flow meter that measures the amount of air that enters the engine. It is between the air cleaner and turbocharger. A small quantity of air that enters the engine indicates deceleration or idle. A large quantity of air that enters the engine indicates acceleration or a high load condition. The MAF sensor has the following circuits:
• | An ignition voltage circuit |
• | A low reference circuit |
• | A MAF sensor signal circuit |
The engine control module (ECM) monitors the MAF sensor signals for voltage outside the normal range of the MAF sensor. If the ECM detects an excessively high MAF sensor signal voltage, this DTC will set.
This diagnostic procedure supports the following DTC:
DTC P2003 Mass Air Flow (MAF) Sensor Circuit High Voltage
• | The ignition switch is ON. |
• | The battery voltage is between 10-16 volts. |
The ECM detects that the MAF signal voltage is more than 4.9 volts.
• | The ECM illuminates the malfunction indicator lamp (MIL) and reduced engine power indicator lamp, if fitted, when the diagnostic runs and fails. |
• | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
• | The ECM limits fuel injection quantity for fail-safe operation. |
• | The ECM closes the exhaust gas recirculation (EGR) valve and stops EGR control. |
• | The ECM inhibits the cruise control. |
• | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
• | Clear the MIL and the DTC with a scan tool. |
• | If an intermittent condition is suspected, the following may cause an intermittent: |
- | Poor connections |
- | A misrouted harness |
- | Rubbed through wire insulation |
- | Broken wire inside the insulation |
• | Inspect for the following conditions: |
- | Poor connection at ECM--Inspect the harness connectors for the following conditions: |
• | Backed-out terminals |
• | Improper mating |
• | Broken locks |
• | Improperly formed or damaged terminals |
• | Poor terminal to wire connection |
- | Damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the Mass Air Flow display on the scan tool while moving the connectors and the wiring harness related to the sensor. A change in the display will indicate the location of the fault. |
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||
2 |
Is DTC P2003 current? | -- | Go to Step 4 | Go to Step 3 | ||||||||
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | |||||||||
4 |
Is the MAF Sensor parameter more than the specified value? | 1 V | Go to Step 6 | Go to Step 5 | ||||||||
5 |
Is the DMM voltage specified value? | Battery Voltage | Go to Step 8 | Go to Step 7 | ||||||||
6 |
Important: The MAF sensor may be damaged by a circuit short to battery voltage.
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 | ||||||||
7 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | ||||||||
8 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 | ||||||||
9 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 | ||||||||
10 | Replace the MAF sensor. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- | ||||||||
11 |
Important: The new ECM must be programmed. Replace the ECM. Refer to Engine Control Module Programming and Setup , Engine Control Module Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming . Did you complete the replacement? | -- | Go to Step 12 | -- | ||||||||
12 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 13 | ||||||||
13 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK |