P1400
Manifold Differential Pressure Sensor Circuit:
Connectors:
CIRCUIT OPERATION
- A 5-volt voltage is applied on the manifold differential pressure sensor power terminal (terminal No.3) from the ECM (terminal No.42)
- A voltage proportional to the pressure in the intake manifold plenum is sent from the manifold differential pressure sensor output terminal (terminal No.1) to the ECM (terminal No.92)
TECHNICAL DESCRIPTION
- The manifold differential pressure sensor outputs a voltage which corresponds to the negative pressure in the intake manifold.
- The ECM
DTC SET CONDITIONS
Check Conditions
- 8 minutes or more have passed after starting the engine. Note that this is only if the engine coolant temperature is less than 0 °C (32 °F) when starting.
- Engine coolant temperature is higher than 45 °C (113 °F).
- Intake air temperature is higher than 0 °C (32 °F).
- Volumetric efficiency is between 30 and 55 percent.
Judgment Criteria
- Manifold differential pressure sensor output voltage has continued to be higher than 4.6 volts [corresponding to an absolute pressure of 118 kPa (17 psi) or higher for 2 seconds.
or
- Manifold differential pressure sensor output voltage has continued to be lower than 0.1 volt [corresponding to an absolute pressure of 2.4 kPa (0.3 psi) or lower for 2 seconds.
Check Conditions
- 8 minutes or more have passed after starting the engine. Note that this is only if the engine coolant temperature is 0 °C (32 °F) or more when starting.
- Engine coolant temperature is higher than 45 °C (113 °F).
- Intake air temperature is higher than 0 °C (32 °F).
- Volumetric efficiency is lower than 30 percent.
Judgment Criteria
- Manifold differential pressure sensor output voltage has continued to be higher than 4.2 volts [corresponding to an absolute pressure of 108 kPa (16 psi) or higher for 2 seconds.
Check Conditions
- 8 minutes or more have passed after starting the engine. Note that this is only if the engine coolant temperature is 0 °C (32 °F) or more when starting.
- Engine coolant temperature is higher than 45 °C (113 °F).
- Intake air temperature is higher than 0 °C (32 °F).
- Volumetric efficiency is higher than 70 percent.
Judgment Criteria
- Manifold differential pressure sensor output voltage has continued to be lower than 1.8 volts [corresponding to an absolute pressure of 46 kPa (4.6 psi) or lower for 2 seconds.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Manifold differential pressure sensor failed.
- Open or shorted manifold differential pressure sensor circuit, or loose connector
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tool:
- MB991502: Scan Tool (MUT-II)
STEP 1. Using scan tool MB991502, check data list item 95: Manifold Differential Pressure 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 95, Manifold Differential Pressure Sensor.
- While engine is idling, pressure should be between 22.6 - 36.0 kPa (6.67 - 10.6 in.Hg).
4. 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 INTRODUCTION, How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check connector B-04 at manifold differential pressure sensor for damage.
Q: Is the connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 3. Measure the sensor supply voltage at manifold differential pressure sensor harness side connector B-04.
1. Disconnect the connector B-04 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal No.3 and ground.
- Voltage should be between 4.8 and 5.2 volts.
4. Turn the ignition switch to "LOCK" (OFF) position.
Q: Is the measured voltage between 4.8 and 5.2 volts?
YES: Go to Step 6.
NO: Go to Step 4.
Connectors:
STEP 4. Check connector C-118 at ECM
Q: Is the connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
Connectors:
STEP 5. Check for open circuit and short circuit to ground between manifold differential pressure sensor connector B-04 (terminal No.3) and ECM connector C-118 (terminal No.42)
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 6. Check the continuity at manifold differential pressure sensor harness side connector B-04.
1. Disconnect the connector B-04 and measure at the harness side.
2. Measure the continuity between terminal No.2 and ground.
- Should be less than 2 ohms.
Q: Is the continuity normal?
YES: Go to Step 9.
NO: Go to Step 7.
Connectors:
STEP 7. Check connector C-118 at ECM
Q: Is the connector in good condition?
YES: Go to Step 8.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
Connectors:
STEP 8. Check for open circuit and harness damage between manifold differential pressure sensor connector B-04 (terminal No.2) and ECM connector C-118 (terminal No.49)
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
Connectors:
STEP 9. Check connector C-122 at ECM
Q: Is the connector in good condition?
YES: Go to Step 10.
NO: Repair or replace it. Refer to Harness Connector inspection. Then go to Step 12.
Connectors:
STEP 10. Check for harness damage between manifold differential pressure sensor connector B-04 (terminal No. 3) and ECM connector C-118 (terminal No.42)
Q: Is the harness wire in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 12.
Connectors:
STEP 11. Check for open circuit and short circuit to ground and harness damage between manifold differential pressure sensor connector B-04 (terminal No.1) and ECM connector C-122 (terminal No.92)
Q: Is the harness wire in good condition?
YES: Replace the manifold differential pressure sensor. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 12. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Trouble Code Diagnosis - OBD-II Drive Cycle - Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P1400 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.