TEST 2: Verifying The Manifold Differential Pressure Is Getting Power
The manifold differential pressure (MDP) sensor is fed power by the by the wire that connects to the MDP sensor connector terminal labeled with the number 3 in the illustration above.
This power is in the form of 5 Volts DC and is supplied by your 2.4L Mitsubishi's Powertrain Control Module (PCM).
We can easily check to see if these 5 Volts are present by doing a simple multimeter voltage test.
These are the steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the MDP sensor from its electrical connector.
- 3
Turn the key On (but don't crank or start the engine).
- 4
Probe the wire that connects to the terminal labeled with the number 3 in the illustration above, with the red multimeter test lead.
- 5
Connect the multimeter's black test lead to the battery's negative (-) post.
- 6
Your multimeter should show read 4.5 to 5 Volts DC.
OK, now that the testing part is done let's take a look at what your results mean:
CASE 1: Terminal #3, of the MDP sensor connector, has 5 Volts DC. This is the correct result and it's starting to look like the MDP sensor is bad but you still need to check that the MDP sensor is getting Ground. For the Ground test, go to: TEST 3: Verifying The MDP Is Getting Ground.
CASE 2: Terminal #3, of the MDP sensor connector, DOES NOT have 5 Volts DC. This results lets you know that the MDP sensor is not bad, since without these 5 Volts DC, the MDP sensor can not function.
Although it's beyond the scope of this article to troubleshoot the cause of these missing 5 Volts, you have now eliminated the MDP sensor as bad. Resolving the issue that is keeping these 5 Volts from being supplied will solve the MDP sensor issue on your 2.4L Mitsubishi Galant (Eclipse or Expo).
TEST 3: Verifying The Manifold Differential Pressure Is Getting Ground
Ground is fed to the manifold differential (MDP) sensor thru' the wire that connects to the MDP sensor connector terminal labeled with the number 2 in the illustration above.
Just like the 5 Volts you tested in TEST 2, Ground is also supplied by your 2.4L Mitsubishi's Powertrain Control Module (PCM).
NOTE: Be careful to not short-circuit this wire accidentally (or intentionally) to battery power or the PCM will get fried. Doing a voltage test with a multimeter, as described in the test steps below, is a safe way to test this circuit.
These are the steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the MDP sensor from its electrical connector.
- 3
Turn the key On (but don't crank or start the engine).
- 4
Probe the wire that connects to the terminal labeled with the number 2 in the illustration above, with the black multimeter test lead.
- 5
Connect the multimeter's red test lead to the battery's positive (+) post.
- 6
Your multimeter should show read 10 to 12 Volts DC.
OK, let's take a look at what your results mean:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct test result and it means that the manifold differential pressure (MDP) sensor on your 2.4L equipped Mitsubishi is fried and needs to be replaced.
Here's why: In MDP sensor TEST 1 and 2, you verified that the MDP sensor is not producing the correct values (when you applied vacuum) and that it does have power. Since in this test step you have confirmed that the MDP sensor does have a solid path to Ground then these results, interpreted together, indicate that the MDP sensor is defective.
CASE 2: The multimeter DID NOT register 10 to 12 Volts. Without Ground the MDP sensor will not function.
Here's why: Without a good path to Ground, that the PCM provides internally, the MDP sensor will not work. With this test result, you have eliminated the MDP sensor as bad.
Although it's beyond the scope of this article to troubleshoot the cause of this missing Ground, you have now eliminated the MDP sensor as bad. Resolving the issue that is keeping Ground from being supplied will solve the MDP sensor issue on your 2.4L Mitsubishi Galant (Eclipse or Expo).
MDP Sensor Code Won't Go Away
So you've tested the manifold differential pressure (MDP) sensor and according to the test results, it's good but the check engine light keeps coming back on even after you erased the diagnostic trouble code (DTC). Well, here in this section are a couple of suggestions that might inspire your next diagnostic move.
Probably the most helpful thing to keep in mind is that the manifold differential pressure sensor (MDP) on your 2.4L Mitsubishi is just used as a feedback sensor. The feedback it sends the PCM is on the EGR system. Specifically, it helps confirm EGR flow into the intake manifold when the PCM commands the EGR valve to open.
So if the MDP sensor tested good (or you've replaced it) and you're still getting a trouble code for it, then:
- There's a good chance that an EGR passage/tube is plugged up and not letting the exhaust gas recirculate.
- The EGR valve itself is bad (internal diaphragm is ruptured and not opening the pintle to let exhaust gas recirculate).
- The EGR Vacuum Solenoid is bad.
More 2.4L Mitsubishi Tutorials
You can find a complete list of 2.4L Mitsubishi tutorials here: Mitsubishi 2.4L Index Of Articles.
Here's a small sample of the tutorials you'll find in the index:
- How To Test The Fuel Injectors (2.4L Mitsubishi).
- How To Test The Throttle Position Sensor (2.4L Mitsubishi).
- How To Test The Engine Compression (Mitsubishi 1.8L, 2.4L).
- Testing A Bad Alternator: Symptoms And Diagnosis.
- How To Bench Test The Starter Motor.
- Blown Head Gasket Test (Mitsubishi 1.8L, 2.4L).
If this info saved the day, buy me a beer!
