Inspection Procedure 31: Manifold Absolute Pressure Sensor System <SOHC>

CONDITION

A power voltage of 5 V is supplied from the engine-A/T-ECU (terminal No. 46) to the manifold absolute pressure sensor power terminal (terminal No. 3) and is grounded from the MDP sensor (terminal No. 2) to the engine-A/T-ECU (terminal No. 57).

The sensor signal is input from the manifold absolute pressure sensor output terminal (terminal No. 1) to the engine-A/T-ECU (terminal No. 91).

FUNCTION

The Manifold absolute pressure sensor detects the internal pressure of the intake manifold by opening and closing the EGR valve for self diagnosis of the exhaust gas recirculation (EGR) system.

In addition to making corrections to the fuel injection volume in accordance with this signal, the engine-A/T-ECU also monitors the operation of the exhaust gas recirculation (EGR) system.

PROBABLE CAUSE

Failed manifold absolute pressure sensor

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

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-II/III data list

Refer to Data list reference table .

Item 32: manifold absolute pressure sensor

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

).
NO: Go to Step 2

STEP 2. Connector check: B-113 manifold absolute pressure sensor connector

Q: Is the check result normal?

YES: Go to Step 3

.
NO: Repair.

STEP 3. Measure voltage at B-113 manifold absolute pressure sensor connector.

Disconnect connector, and measure at harness side.

Ignition switch: ON

Voltage between terminal No. 3 and earth.

OK: 4.9 - 5.1 V

Q: Is the check result normal?

YES: Go to Step 9

.
NO: Go to Step 4

STEP 4. Measure voltage at C-111 engine-A/T-ECU connector.

Measure engine-A/T-ECU terminal voltage.

Ignition switch: ON

Voltage between terminal No. 46 and earth.

OK: 4.9 - 5.1 V

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Go to Step 6

STEP 5. Connector check: C-111 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between B-113 (terminal No. 3) manifold absolute pressure sensor connector and C-111 (terminal No. 46) engine-A/T-ECU connector.

Check power supply line for open circuit.

NO: Repair.

STEP 6. Connector check: C-111 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 7

.
NO: Repair.

STEP 7. Check harness between B-113 (terminal No. 3) manifold absolute pressure sensor connector and C-111 (terminal No. 46) engine-A/T-ECU connector.

Check power supply line for short circuit.

Q: Is the check result normal?

YES: Go to Step 8

.
NO: Repair.

STEP 8. MUT-II/III data list

Refer to Data list reference table .

Item 32: manifold absolute pressure sensor

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

).
NO: Replace engine-A/T-ECU.

STEP 9. Perform resistance measurement at B-113 manifold absolute pressure sensor connector.

Disconnect connector, and measure at harness side.

Resistance between terminal No. 2 and earth.

OK: 2 Ω or less

Q: Is the check result normal?

YES: Go to Step 12

.
NO: Go to Step 10

STEP 10. Connector check: C-111 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 11

.
NO: Repair.

STEP 11. Check harness between B-113 (terminal No. 2) manifold absolute pressure sensor connector and C-111 (terminal No. 5) engine-A/T-ECU connector.

Check earthing line for open circuit and damage.

Q: Is the check result normal?

YES: Go to Step 8

.
NO: Repair.

STEP 12. Perform resistance measurement at B-113 manifold absolute pressure sensor connector.

Use special tool test harness (MB991348) to connect connector, and measure at pick-up harness.

Ignition switch: ON

Resistance between terminal No. 3 and earth.

OK: 4.9 - 5.1 V

Q: Is the check result normal?

YES: Go to Step 14

.
NO: Go to Step 13

STEP 13. Connector check: C-111 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between B-113 (terminal No. 3) manifold absolute pressure sensor connector and C-111 (terminal No. 46) engine-A/T-ECU connector.

Check power supply line for damage.

NO: Repair.

STEP 14. Perform resistance measurement at B-113 manifold absolute pressure sensor connector.

Use special tool test harness (MD991348) to connect connector, and measure at pick-up harness.

Ignition switch: ON

Resistance between terminal No. 2 and earth.

OK: 0.5 V

Q: Is the check result normal?

YES: Go to Step 16

.
NO: Go to Step 15

STEP 15. Connector check: C-111 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between B-113 (terminal No. 2) manifold absolute pressure sensor connector and C-111 (terminal No. 57) engine-A/T-ECU connector.

Check earthing line for damage.

NO: Repair.

STEP 16. Perform voltage measurement at B-113 manifold absolute pressure sensor connector.

Use special tool test harness (MD991348) to connect connector, and measure at pick-up harness.

Voltage between terminal No. 1 and earth.

OK:

Idling: 0.8 - 2.4 V

Voltage decrease temporarily when accelerator pedal is abruptly depressed during idling state.

Q: Is the check result normal?

YES: Go to Step 19

.
NO: Go to Step 17

STEP 17. Check connector: C-110 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 18

.
NO: Repair.

STEP 18. Check harness between B-113 (terminal No. 1) manifold absolute pressure sensor connector and C-110 (terminal No. 91) engine-A/T-ECU connector.

Check output line for short circuit and damage.

Q: Is the check result normal?

YES: Replace manifold absolute pressure sensor.
NO: Repair.

STEP 19. Measure voltage at C-110 engine-A/T-ECU connector.

Measure engine-A/T-ECU terminal voltage.

Voltage between terminal No. 91 and earth.

OK:

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?

YES: Go to Step 21

.
NO: Go to Step 20

STEP 20. Connector check: C-110 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between B-113 (terminal No. 1) manifold absolute pressure sensor connector and C-110 (terminal No. 91) engine-A/T-ECU connector.

Check output line for open circuit and damage.

NO: Repair.

STEP 21. Connector check: C-110 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 8

.
NO: Repair.


Inspection Procedure 31: Manifold Absolute Pressure Sensor System <SOHC>

CONDITION A power voltage of 5 V is supplied from the engine-A/T-ECU (terminal No. 46) to the manifold absolute pressure sensor power terminal (terminal No. 3) and is grounded from the MDP sensor (terminal No. 2) to the engine-A/T-ECU (terminal No. 57). The sensor signal is input from the manifold absolute pressure sensor output terminal (terminal No. 1) to the engine-A/T-ECU (terminal No. 91).
FUNCTION The Manifold absolute pressure sensor detects the internal pressure of the intake manifold by opening and closing the EGR valve for self diagnosis of the exhaust gas recirculation (EGR) system. In addition to making corrections to the fuel injection volume in accordance with this signal, the engine-A/T-ECU also monitors the operation of the exhaust gas recirculation (EGR) system.
PROBABLE CAUSE Failed manifold absolute pressure sensor Open/short circuit in manifold absolute pressure sensor circuit or loose connector contact Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. MUT-II/III data list Refer to Data list reference table . Item 32: manifold absolute pressure sensor Q: Is the check result normal? YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ). NO: Go to Step 2 .
	STEP 2. Connector check: B-113 manifold absolute pressure sensor connector
	Q: Is the check result normal? YES: Go to Step 3 . NO: Repair.
	STEP 3. Measure voltage at B-113 manifold absolute pressure sensor connector.
	Disconnect connector, and measure at harness side. Ignition switch: ON Voltage between terminal No. 3 and earth. OK: 4.9 - 5.1 V Q: Is the check result normal? YES: Go to Step 9 . NO: Go to Step 4 .
	STEP 4. Measure voltage at C-111 engine-A/T-ECU connector.
	Measure engine-A/T-ECU terminal voltage. Ignition switch: ON Voltage between terminal No. 46 and earth. OK: 4.9 - 5.1 V Q: Is the check result normal? YES: Go to Step 5 . NO: Go to Step 6 .
	STEP 5. Connector check: C-111 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between B-113 (terminal No. 3) manifold absolute pressure sensor connector and C-111 (terminal No. 46) engine-A/T-ECU connector. Check power supply line for open circuit. NO: Repair.
	STEP 6. Connector check: C-111 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 7 . NO: Repair.
	STEP 7. Check harness between B-113 (terminal No. 3) manifold absolute pressure sensor connector and C-111 (terminal No. 46) engine-A/T-ECU connector.
	Check power supply line for short circuit. Q: Is the check result normal? YES: Go to Step 8 . NO: Repair.
	STEP 8. MUT-II/III data list Refer to Data list reference table . Item 32: manifold absolute pressure sensor Q: Is the check result normal? YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ). NO: Replace engine-A/T-ECU.
	STEP 9. Perform resistance measurement at B-113 manifold absolute pressure sensor connector.
	Disconnect connector, and measure at harness side. Resistance between terminal No. 2 and earth. OK: 2 Ω or less Q: Is the check result normal? YES: Go to Step 12 . NO: Go to Step 10 .
	STEP 10. Connector check: C-111 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 11 . NO: Repair.
	STEP 11. Check harness between B-113 (terminal No. 2) manifold absolute pressure sensor connector and C-111 (terminal No. 5) engine-A/T-ECU connector.
	Check earthing line for open circuit and damage. Q: Is the check result normal? YES: Go to Step 8 . NO: Repair.
	STEP 12. Perform resistance measurement at B-113 manifold absolute pressure sensor connector.
	Use special tool test harness (MB991348) to connect connector, and measure at pick-up harness. Ignition switch: ON Resistance between terminal No. 3 and earth. OK: 4.9 - 5.1 V Q: Is the check result normal? YES: Go to Step 14 . NO: Go to Step 13 .
	STEP 13. Connector check: C-111 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between B-113 (terminal No. 3) manifold absolute pressure sensor connector and C-111 (terminal No. 46) engine-A/T-ECU connector. Check power supply line for damage. NO: Repair.
	STEP 14. Perform resistance measurement at B-113 manifold absolute pressure sensor connector.
	Use special tool test harness (MD991348) to connect connector, and measure at pick-up harness. Ignition switch: ON Resistance between terminal No. 2 and earth. OK: 0.5 V Q: Is the check result normal? YES: Go to Step 16 . NO: Go to Step 15 .
	STEP 15. Connector check: C-111 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between B-113 (terminal No. 2) manifold absolute pressure sensor connector and C-111 (terminal No. 57) engine-A/T-ECU connector. Check earthing line for damage. NO: Repair.
	STEP 16. Perform voltage measurement at B-113 manifold absolute pressure sensor connector.
	Use special tool test harness (MD991348) to connect connector, and measure at pick-up harness. Voltage between terminal No. 1 and earth. OK: Idling: 0.8 - 2.4 V Voltage decrease temporarily when accelerator pedal is abruptly depressed during idling state. Q: Is the check result normal? YES: Go to Step 19 . NO: Go to Step 17 .
	STEP 17. Check connector: C-110 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 18 . NO: Repair.
	STEP 18. Check harness between B-113 (terminal No. 1) manifold absolute pressure sensor connector and C-110 (terminal No. 91) engine-A/T-ECU connector.
	Check output line for short circuit and damage. Q: Is the check result normal? YES: Replace manifold absolute pressure sensor. NO: Repair.
	STEP 19. Measure voltage at C-110 engine-A/T-ECU connector.
	Measure engine-A/T-ECU terminal voltage. Voltage between terminal No. 91 and earth. OK: 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? YES: Go to Step 21 . NO: Go to Step 20 .
	STEP 20. Connector check: C-110 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between B-113 (terminal No. 1) manifold absolute pressure sensor connector and C-110 (terminal No. 91) engine-A/T-ECU connector. Check output line for open circuit and damage. NO: Repair.
	STEP 21. Connector check: C-110 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 8 . NO: Repair.