DTC P0103 Mass Air Flow (MAF) Sensor Circuit High Frequency. Pontiac Sun Runner - 4WD (Canada) 1997

For 1990-2009 cars
Engine Controls Schematics

### Circuit Description

The mass air flow (MAF) sensor measures the amount of air which passes through it in a given amount of time. The Powertrain Control Module (PCM) uses this information to determine the operating requirements of the engine in order to control fuel delivery. The PCM calculates the engine's fuel requirements by monitoring the current flow on the signal wire from the MAF sensor. When the volume of air entering the MAF sensor increases, the current flow seen by the PCM from the MAF sensor also increases. When the air flow decreases, the current seen by the PCM also decreases. The MAF sensor is located between the air intake tube and the air cleaner in the LH front area of the engine compartment.

### Conditions for Running the DTC

The engine is running.

### Conditions for Setting the DTC

• | MAF sensor output current is greater than 4.9 mA.

• | Condition is present for longer than 5 seconds.

### Action Taken When the DTC Sets

• | The malfunction indicator lamp (MIL) will illuminate.

• | The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.

• | The PCM will enter the Fail-Safe Function and determine injector drive time according to TP sensor and engine speed.

### Conditions for Clearing the MIL/DTC

• | The MIL will turn off after three consecutively passing cycles without a fault present.

• | A History DTC will clear after 40 consecutive warm-up cycles without a fault.

• | DTCs can be cleared by using a scan tool or by disconnecting the PCM battery feed.

### Diagnostic Aids

Check for any of the following conditions:

• | MAF sensor readings vary with the air temperature and barometric pressure. The specifications indicated are at 20°C (68°F) and sea level.

• | A misrouted wiring harness. Inspect the MAF sensor harness to ensure that it is not routed too close to high voltage wires such as spark plug leads.

• | A damaged wiring 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.

• | Check for a restriction. A plugged intake air duct or a dirty air filter element. A wide open throttle (WOT) acceleration from a stop should cause the MAF displayed on the scan tool to increase from about 2 to 3.5 grams per second at idle to 100 grams per second or greater at the time of the 1-2 shift.

An intermittent malfunction may be caused by a fault in the MAF sensor circuit. Inspect the wiring harness and components for any of the following conditions:

• | Backed out terminals.

• | Improper mating of terminals.

• | Broken electrical connector locks.

• | Improperly formed or damaged terminals.

• | Faulty terminal to wire connections.

• | Physical damage to the wiring harness.

• | A broken wire inside the insulation.

• | Corrosion of electrical connections, splices, or terminals.

If the DTC P0103 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

### Test Description

The numbers below refer to the step numbers in the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. This step will determine if the fault is present.

3. Review Freeze Frame data to determine when the DTC set. Always record this information.

4. Normal voltage at idle for the MAF sensor signal circuit should be 1.7 volts to 2.0 volts. This voltage reading should increase steadily to 5 volts when engine speed is increased to approximately 4000 RPM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check

2

1. Start the engine.
2. Install a scan tool.
3. With the throttle closed, select the MAF sensor parameter on the scan tool.

Is the MAF sensor display above the specified value?

21.2 g/sec

Go to Step 4

Go to Step 3

3

1. Turn ON the ignition, leaving the engine OFF.
2. Perform the scan tool Clear DTC Information function.
3. Operate the vehicle within the Freeze Frame conditions as noted.

Is DTC P0103 set?

--

Go to Step 4

Fault Not Present-Go to Diagnostic Aids

4

1. Turn ON the ignition, leaving the engine OFF.
2. Backprobe the MAF sensor signal circuit at the PCM, using a DMM connected to ground.
3. Measure the voltage.

Is the voltage within the specified value?

1.0 to 1.6 volts

Go to Step 5

Go to Step 6

5

Important: MAF sensor readings vary with the air temperature and barometric pressure. The specifications indicated are at 20°C (68°F) and sea level.

1. Leave the DMM connected.
2. Start the engine.
3. Measure the voltage while increasing the engine speed to approximately 4000 RPM (briefly). Refer to the Test Description.

Does the voltage rise approximately to the specified value when the engine speed is increased?

From 1.6 volts at idle up to 3.0 volts at 4000 RPM

Go to Step 10

Go to Step 11

6

1. Turn OFF the ignition.
2. Disconnect the MAF sensor electrical connector.
3. Probe the MAF sensor ground circuit, using a test light connected to B+.

Is the test light ON?

--

Go to Step 7

Go to Step 8

7 | Check for a faulty connection at the MAF sensor and at the PCM. Repair as necessary. Was a repair necessary? | -- | Go to Step 12 | Go to Step 9
8 | Locate and repair the open circuit in the ground circuit to the MAF sensor. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 12 | --
9 | Check for a short circuit in the MAF sensor signal circuit. Repair as necessary. Refer to Wiring Repairs in Wiring Systems. Was a repair necessary? | -- | Go to Step 12 | Go to Step 11
10 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 12 | --
11 | Replace the MAF sensor. Refer to Mass Airflow Sensor Replacement . Is the action complete? | -- | Go to Step 12 | --

12

1. Perform the scan tool Clear DTC Information function and road test vehicle within Freeze Frame conditions that set the DTC.
2. Review the scan tool data and check for DTCs. The repair is complete if no DTCs are stored.

Are any DTCs displayed on the scan tool?

--

Go to the Applicable DTC Table

System OK