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 (terminal No. 2) from the engine-ECU (terminal No. 44) and earthed to the engine-ECU (terminal No. 46) from the manifold absolute pressure sensor (terminal No. 4).
The sensor signal is inputted to the engine-ECU (terminal No. 45) from the manifold absolute pressure sensor output terminal (terminal No. 1).

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 JUDGMENT

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. Connector check: B-14 manifold absolute pressure sensor connector

Q. Is the check result normal?

	Go to Step 3 .

	Repair or replace the connector.

STEP 3. Perform voltage measurement at B-14 manifold absolute pressure sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 2 and earth.

OK: 4.9 - 5.1 V

Q. Is the check result normal?

	Go to Step 7 .

	Go to Step 4 .

STEP 4. Connector check: B-26 engine-ECU connector

Q. Is the check result normal?

	Go to Step 5 .

	Repair or replace the connector.

STEP 5. Check harness between B-14 (terminal No. 2) manifold absolute pressure sensor connector and B-26 (terminal No. 44) engine-ECU connector.

Check power supply line for open/short circuit.

Q. Is the check result normal?

	Go to Step 6 .

	Repair the damaged harness wire.

STEP 6. 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 7. Connector check: B-26 engine-ECU connector

Q. Is the check result normal?

	Go to Step 8 .

	Repair or replace the connector.

STEP 8. Check harness between B-14 (terminal No. 2) manifold absolute pressure sensor connector and B-26 (terminal No. 44) engine-ECU connector.

Check power supply line for damage.

Q. Is the check result normal?

	Go to Step 9 .

	Repair the damaged harness wire.

STEP 9. Perform voltage measurement at B-14 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 No. 1 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 11 .

	Go to Step 10 .

STEP 10. Check harness between B-14 (terminal No. 1) manifold absolute pressure sensor connector and B-26 (terminal No. 45) engine-ECU connector.

Check output line for short circuit.

Q. Is the check result normal?

	Replace the manifold absolute pressure sensor.

	Repair the damaged harness wire.

STEP 11. Connector check: B-26 engine-ECU connector

Q. Is the check result normal?

	Go to Step 12 .

	Repair or replace the connector.

STEP 12. Perform voltage measurement at B-26 engine-ECU connector.

Disconnect engine-ECU harness, and connect special tool power plant ECU check harness (MB992110) to measure at connector for inspection.
Ignition switch: ON
Voltage between terminal No. 45 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 6 .

	Check and repair harness between B-14 (terminal No. 1) manifold absolute pressure sensor connector and B-26 (terminal No. 45) engine-ECU connector. Check output line for open circuit and damage.