How To Test The MAP Sensor (1997-2001 2.2L Toyota Camry)

TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts

In TEST 1, you confirmed that the MAP sensor on your 2.2L Toyota Camry is either not producing a variable signal or the signal is stuck in one value.

In this step, you'll verify that the MAP sensor is receiving power. Without power (5 Volts), it simply won't function.

These 5 Volts are supplied by the PCM (Powertrain Control Module = the fuel injection computer) thru the yellow (YEL) wire of the MAP sensor's 3-wire connector.

In the photo of the connector above, the terminal labeled with the number 1 is the one that connects to the YEL wire.

Alright, this is what you'll need to do:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the MAP sensor from its electrical connector.

3. 3

   Turn the key ON but don't crank or start the engine.

4. 4

   Probe the terminal labeled with the number 1 (see the image above) with the red multimeter test lead.

5. 5

   Connect the black multimeter test lead to the battery's negative (-) post.

6. 6

   Your multimeter should show you 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: The multimeter registered 5 Volts. This is the correct and expected test result.

Your next step is to check that the MAP sensor is getting Ground. Go to: TEST 3: Making Sure The MAP Sensor Is Getting Ground.

CASE 2: The multimeter DID NOT register 5 Volts. This results lets you know that the MAP sensor is not bad, since without these 5 Volts DC, the MAP 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 MAP sensor as bad.

Resolving the issue that's keeping these 5 Volts from being supplied will solve the MAP sensor issue on your 2.2L Toyota Camry.

TEST 3: Making Sure The MAP Sensor Is Getting Ground

Up to this point, you have confirmed that:

• The MAP voltage signal is stuck in one value (TEST 1).
• The MAP sensor is getting power (TEST 2).

In this step, you'll verify that the MAP sensor is getting Ground from the PCM. Without Ground, the MAP sensor won't function.

This Ground supplied by the PCM thru the brown (BRN) wire of the MAP sensor's 3-wire connector.

In the photo of the connector above, the terminal labeled with the number 3 is the one that connects to the BRN wire.

IMPORTANT: Since this circuit is directly connected to the PCM, be very careful and don't short (connect) this wire to battery power (12 Volts), or you WILL FRY the PCM.

Let's get started:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the MAP sensor from its electrical connector.

3. 3

   Turn the key ON but don't crank or start the engine.

4. 4

   Probe the terminal labeled with the number 3 (see image above), with the black multimeter test lead.

5. 5

   Connect the red multimeter test lead on the battery's positive (+) post.

6. 6

   Your multimeter should show 10 to 12 Volts.

OK, let's take a look at what your results mean:

CASE 1: The multimeter registered 12 Volts. This is the normal and expected test result.

It confirms that the MAP sensor is getting Ground. This test result also tells you that the MAP sensor is bad only if you have

• Confirmed that the MAP sensor is not producing a MAP signal (TEST 1).
• Confirmed it's getting power (5 Volts) (TEST 2).
• Confirmed it's getting Ground (this test section).

If the MAP sensor is defective, take a look at: Where To Buy The MAP Sensor And Save.

CASE 2: The multimeter DID NOT register 12 Volts. Double check your multimeter connections and repeat the test.

If your multimeter results still do not indicate 10 to 12 Volts, then the MAP is not fried and not the cause of the MAP diagnostic trouble code (DTC) issue.

Here's why: Without a good path to Ground, that the PCM provides internally, the MAP sensor will not work. With this test result, you have eliminated the MAP sensor itself as bad.

The MAP Sensor Code Won't Go Away

So, you've tested the MAP sensor, and the results indicate it's OK (not defective). Yet, the check engine light keeps coming back on, even after you've erased the diagnostic trouble code (DTC) from the PCM's memory.

Here are a few potential issues that will cause the PCM to think the MAP sensor is bad and set a MAP sensor trouble code:

• Cracked or leaking vacuum hose: The vacuum hose connected to the MAP sensor might be cracked, loose, or leaking, causing the sensor to receive incorrect readings. Inspect the vacuum hose thoroughly and replace it if damaged.
• Low Engine Compression: Several cylinders may have very low compression, causing rough idling and low or erratic vacuum. I recommend performing a compression test to confirm this.
• Intermittent MAP Sensor Failure: The MAP sensor might be working most of the time but failing intermittently. To test this, gently tap the MAP sensor with the handle of a screwdriver while applying vacuum and see if the voltage readings fluctuate or fail.
• Loose or Damaged Connector: The MAP sensor's connector could be faulty, often due to a broken locking tab, which can cause a loose connection and intermittent issues. Check the connector and secure or replace it if necessary.
• Fuel Pump Issues: The fuel pump may be failing, resulting in insufficient fuel delivery or low pressure to the injectors. I suggest conducting a fuel pump test to rule this out.

More 2.2L Toyota Camry Tutorials

You can find a complete list of 2.2L Toyota Camry tutorials and wiring diagrams in this index:

• 2.2L Toyota Camry And Celica Index of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test Engine Compression (1990-2001 2.2L Toyota Camry, Celica).
• How To Test The TPS With A Multimeter (1997-2001 2.2L Toyota Camry).
• How To Test For A Blown Head Gasket (1990-2001 2.2L Toyota Camry, Celica).
• How To Test The Throttle Position Sensor (1992-1996 2.2L Toyota Camry).