P0103

Connectors:

CIRCUIT OPERATION
- The volume air flow sensor power is supplied from the MFI relay (terminal 1), and the ground is provided on the ECM (terminal 49) or PCM (terminal 57) .
- 5-volt power is applied to the volume air flow sensor output terminal (terminal 3) from the ECM (terminal 61) or PCM (terminal 65) . The volume air flow sensor generates a pulse signal when the output terminal and ground are opened/closed (opened/short).

TECHNICAL DESCRIPTION
- While the engine is running, the volume air flow sensor outputs a pulse signal which corresponds to the volume of air flow.
- The ECM or PCM checks whether the frequency of this signal output by the volume air flow sensor while the engine is running is at or above the set value.
- When the throttle position sensor output voltage is low, the ECM or PCM causes the power transistor to be "ON" to send an air flow sensor reset signal to the air flow sensor. In response to the reset signal, the air flow sensor resets the filter circuit and improves the ability of the air flow sensor to measure the amount of air in a small air intake region.

DTC SET CONDITIONS

Check Conditions
- Throttle position sensor voltage is 2 volts or lower.
- Engine speed is lower than 2,000 r/min.
- Judgement Criteria
- Volume air flow sensor output frequency has continued to be 800 Hz or higher for 2 seconds.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Volume air flow sensor failed.
- Open or shorted volume air flow sensor circuit, or loose connector.
- ECM failed.
- PCM failed.
- Air leak between volume air flow sensor and throttle body.

DIAGNOSIS

Required Special Tools
MB991502: Scan Tool(MUT-II)

STEP 1. Using scan tool MB991502, check data list item 12: Volume Air Flow Sensor.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK"(OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991502 to the data reading mode for item 12, Volume Air Flow Sensor.
4. Warm up the engine to normal operating temperature: 80 °C to 96 °C (176 °F to 205 °F).
- The standard value during idling should be 10 Hz or more.
- When the engine is revved, the frequency should increase according to the increase in engine speed.

5. Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the sensor operating properly?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points.

NO: Go to Step 2.

STEP 2. Check the reset signal voltage at volume air flow sensor connector B-14 by backprobing.
1. Do not disconnect the connector B-14.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 7 and ground by backprobing.
- Voltage should be between 6.0 and 9.0 volts.
4. Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the voltage normal?

YES: Go to Step 5.

NO: Go to Step 3.

STEP 3. Check connector B-14 at volume air flow sensor and connector C-111 at ECM or connector C-112 at PCM for damage.

Q: Is the connector in good condition?

YES: Go to Step 4.

NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 9.

STEP 4. Check for short circuit to ground between volume air flow sensor connector B-14 terminal 7 and ECM connector C-111 terminal 19 or PCM connector C-112 terminal 19 .

Q: Is the harness wire in good condition?

YES: Replace the volume air flow sensor. Then go to Step 9.

NO: Repair it. Then go to Step 9.

STEP 5. Check the reset signal voltage at volume air flow sensor connector B-14 by backprobing.
1. Do not disconnect the connector B-14.
2. Start the engine and run at idle.
3. Measure the voltage between terminal 7 and ground by backprobing.
- When the engine idling, voltage should be 1.0 volt or less.
- When the engine speed is 3000 r/min, voltage should be between 6.0 and 9.0 volts.

4. Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the voltage normal?

YES: Go to Step 8.

NO: Go to Step 6.

STEP 6. Check connector B-14 at volume air flow sensor and connector C-111 at ECM or connector C-112 at PCM for damage.

Q: Is the connector in good condition?

YES: Go to Step 7.

NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 9.

STEP 7. Check for open circuit and harness damage between volume air flow sensor connector B-14 terminal 7 and ECM connector C-111 terminal 19 or PCM connector C-112 terminal 19 .

Q: Is the harness wire in good condition?

YES: Replace the ECM or PCM. Then go to Step 9.

NO: Repair it. Then go to Step 9.

STEP 8. Replace the volume air flow sensor.
1. Replace the volume air flow sensor.
2. Carry out a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
3. Check the diagnostic trouble code (DTC).

Q: Is the DTC P0103 is output?

YES: Replace the ECM or PCM. Then go to Step 9.

NO: The inspection is complete.

STEP 9. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code(DTC).

Q: Is the DTC P0103 is output?

YES: Retry the troubleshooting.

NO: The inspection is complete.