Code No. P0107: Manifold Absolute Pressure Sensor Circuit Low Input

OPERATION

A power voltage of 5 V is applied to the manifold absolute pressure sensor power terminal from the engine-ECU connector terminal 5V&B/S5 and earthed to the engine-ECU connector terminal SENG from the manifold absolute pressure sensor earth terminal.
The sensor signal is inputted to the engine-ECU connector terminal B/S from the manifold absolute pressure sensor output terminal.

FUNCTION

The manifold absolute pressure sensor detects a change in inlet manifold pressure and inputs the signal to the engine-ECU.
In response to the signal, the engine-ECU corrects the fuel injection amount, etc.

TROUBLE JUDGEMENT

Check Conditions

2 seconds later after the ignition switch has been in ON position or just after the engine has started up.
Throttle position sensor (main) output voltage is 1.3 V or more or the vehicle is at halt.

Judgement Criterion

Manifold absolute pressure sensor output voltage is less than 0.2 V (corresponding to a manifold absolute pressure of 5 kPa or less) for 2 seconds.

FAIL-SAFE AND BACKUP FUNCTION

Control as if the inlet manifold vacuum pressure is 101 kPa.

PROBABLE CAUSES

Failed manifold absolute pressure sensor
Open/short circuit or harness damage in manifold absolute pressure sensor circuit or loose connector contact

Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Data list reference table (Refer to ).

Item 8: Manifold absolute pressure sensor

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 2.

STEP 2. Perform voltage measurement at manifold absolute pressure sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal 5V&B/S5 line and earth.

OK: 4.9 - 5.1 V

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 3.

STEP 3. Check of open circuit, and short circuit in 5V&B/S5 line between manifold absolute pressure sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 4.

	Repair the connector(s) or wiring harness.

STEP 4. M.U.T.-III data list

Data list reference table (Refer to ).

Item 8: Manifold absolute pressure sensor

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Replace the engine-ECU.

STEP 5. Check of damage in 5V&B/S5 line between manifold absolute pressure sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 6.

	Repair the connector(s) or wiring harness.

STEP 6. Perform voltage measurement at manifold absolute pressure sensor connector.

Use special tool test harness (MB991348) to connect connector, and measure at pick-up harness.
Ignition switch: ON
Voltage between terminal B/S line and earth.

Altitude 0 m: 3.8 - 4.2 V
Altitude 600 m: 3.5 - 3.9 V
Altitude 1,200 m: 3.3 - 3.7 V
Altitude 1,800 m: 3.0 - 3.4 V

Q. Is the check result normal?

	Go to Step 8.

	Go to Step 7.

STEP 7. Check of short to earth in B/S line between manifold absolute pressure sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Replace the manifold absolute pressure sensor.

	Repair the connector(s) or wiring harness.

STEP 8. Perform voltage measurement at engine-ECU connector.

Measure engine-ECU terminal voltage.
Ignition switch: ON
Voltage between terminal B/S and earth.

Altitude 0 m: 3.8 - 4.2 V
Altitude 600 m: 3.5 - 3.9 V
Altitude 1,200 m: 3.3 - 3.7 V
Altitude 1,800 m: 3.0 - 3.4 V

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector(s), or check and repair the harness of open circuit, and damage in B/S line between manifold absolute pressure sensor connector and engine-ECU connector.