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 voltage parameter and as a grams per second (g/s) parameter. If the ECM detects that the actual MAF sensor voltage signal is more than the possible range of a normally operating sensor DTC P0103 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0103 Mass Air Flow (MAF) Sensor Circuit High Voltage.
Conditions for Running the DTC
| • | DTC P0112, P0113 are not set. |
| • | The engine is running for more than 2 seconds. |
| • | The engine speed is between 500-2,500 RPM. |
| • | The ignition 1 signal is more than 9 volts. |
| • | The IAT Sensor parameter is more than -7°C (19°F). |
| • | The above conditions are met for more than 3 seconds. |
| • | DTC P0103 runs continuously within the enabling conditions. |
Conditions for Setting the DTC
The ECM detects that the MAF sensor voltage signal is more than 4.5 volts for more than 6 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. |
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |||||||
2 |
Is the MAF Sensor parameter more than the specified value? | 4.5 V | Go to Step 4 | Go to Step 3 | ||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Inducing Intermittent Fault Conditions in Wiring Systems and Intermittent Conditions | ||||||
4 |
Does the movement of the harness or the connector affect the MAF Sensor parameter? | -- | Go to Step 14 | Go to Step 5 | ||||||
5 |
Is the MAF Sensor parameter more than the specified value? | 4.5 V | Go to Step 9 | Go to Step 6 | ||||||
6 |
Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 7 | ||||||
7 |
Important: All electrical components and accessories must be turned OFF.
Is the resistance less than the specified value? | 5 ohms | Go to Step 11 | Go to Step 8 | ||||||
8 |
Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 12 | ||||||
9 |
Important:: Disconnecting the harness connectors of the ECM may eliminate the short to voltage if the signal circuit is shorted to another ECM circuit.
Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 10 | ||||||
10 | Measure the resistance from the signal circuit of the MAF sensor to all other circuits at all ECM connectors with a DMM. Refer to Circuit Testing in Wiring Systems. Is the resistance less than the specified value? | ∞ ohms | Go to Step 13 | Go to Step 12 | ||||||
11 | Test for an intermittent and for a poor connection at the MAF/IAT sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 | ||||||
12 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 16 | ||||||
13 | Repair the circuits that are shorted together. Refer to Wiring Repairs in Wiring Systems Did you complete the repair? | -- | Go to Step 17 | -- | ||||||
14 | Repair the harness or the connections as necessary. Refer to Wiring Repairs and Connector Repairs and Repairing Connector Terminals in Wiring Systems. Did you complete the repair? | -- | Go to Step 17 | -- | ||||||
15 | Replace the MAF/IAT sensor. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- | ||||||
16 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- | ||||||
17 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 18 | ||||||
18 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||
