P1400
Manifold Differential Pressure Sensor Circuit:
Connectors:
CIRCUIT OPERATION
- A 5-volt voltage is applied on the manifold differential pressure sensor power terminal (terminal 3) from the ECM (terminal 81)
- A voltage proportional to the pressure in the intake manifold plenum is sent from the manifold differential pressure sensor output terminal (terminal 1) to the ECM (terminal 73)
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 45 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 5 °C (41 °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 Tools
- 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 62 and 76 kPa.
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 How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check connector B-102 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. Check the sensor supply voltage at manifold differential pressure sensor harness side connector B-102.
1. Disconnect the connector B-102 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 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 voltage normal?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check connector C-115 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.
STEP 5. Check for open circuit and short circuit to ground between manifold differential pressure sensor connector B-102 terminal 3 and ECM connector C-115 terminal 81
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-102.
1. Disconnect the connector B-102 and measure at the harness side.
2. Measure the continuity between terminal 2 and ground.
- Should be less than 2 ohm.
Q: Is the continuity normal?
YES: Go to Step 9.
NO: Go to Step 7.
STEP 7. Check connector C-115 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.
STEP 8. Check for open circuit and harness damage between manifold differential pressure sensor connector B-102 terminal 2 and ECM connector C-115 terminal 92
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 9. Check connector C-115 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.
STEP 10. Check for harness damage between manifold differential pressure sensor connector B-102 terminal 3 and ECM connector C-115 terminal 81
Q: Is the harness wire in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 12.
STEP 11. Check for open circuit and short circuit to ground and harness damage between manifold differential pressure sensor connector B-102 terminal 1 and ECM connector C-115 terminal 73
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, Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is the DTC P1400 output?
YES: Retry the troubleshooting.
NO: The inspection is complete.