How To Clean A Bad Map Sensor On A 2004 Buick Lesabre

Dan Ferrell writes virtually exercise-it-yourself car maintenance and repair. He has certifications in automation and control technology.

MAP sensor on footwell within engine compartment.

Photo courtesy of Brian Snelson on Flickr

Bad MAP Sensor Symptoms

A bad manifold absolute pressure (MAP) sensor can upset fuel commitment and ignition timing. Depending on your vehicle model, your engine might feel one or more than of these performance problems:

• Rich air-fuel ratio
• Lean air-fuel ratio
• Surging
• Poor fuel economy
• It won't first
• Lack of engine power
• Stalling
• Detonation and misfire

However, these symptoms are not exclusively symptoms of a failed MAP sensor. Sometimes, a bad sensor may trigger the check engine light (CEL). If a problem lawmaking has been stored on the computer retention indicating a trouble with the MAP sensor, it's a good idea to actually test the sensorm to ostend that the trouble lies with the sensor and not some other related component.

What Yous'll Need to Troubleshoot a MAP Sensor

Troubleshooting a MAP sensor is a straightforward process using a digital multimeter (DMM) and a manus-held vacuum pump. If y'all don't accept the pump, your local auto parts store may lend you one.

In the following sections, y'all'll detect some important information virtually the sensor, what to pay attending to during your inspection, and a simple MAP-sensor exam procedure. Continue in mind that these tests employ to gasoline, four-bicycle internal combustion engines without a turbo or supercharger. If necessary, consult the vehicle repair manual for your specific model.

Answers You'll Notice In This Article

1. What Does a Map Sensor Practice?
2. Does My Car Accept a MAP Sensor?
3. P0105 and Other MAP Problem Codes
4. MAP Sensor Location
5. How to Exam a MAP Sensor
6. Checking the MAP Sensor Reference Signal
7. Sensor Voltage Drop Reference Table
8. Testing a Digital MAP Sensor
9. MAP Sensor Replacement
10. Should I Replace the MAP Sensor?

Audit the map sensor wires for damage during your diagnostic.

Photograph courtesy of Brian Snelson on Wikimedia

I. What Does a Map Sensor Do?

Basically, a MAP sensor reads the corporeality of air pressure in relation to vacuum inside the intake manifold, either straight or using a vacuum hose. Then, it translates this force per unit area into a voltage signal that the sensor feeds to the power control module (PCM), your machine's computer.

The sensor uses a 5 volt reference indicate that comes from the computer to return the signal.

Changes in vacuum or air pressure in the intake manifold varies the electric resistance in the sensor, increasing or reducing the indicate's voltage to the estimator.

The PCM uses the MAP sensor'southward information along with input from other sensors to accommodate fuel commitment to the cylinders and ignition timing according to electric current engine load and speed.

Some vehicles utilize a mass air flow sensor (MAF) instead of a MAP sensor. Some use both.

Photo courtesy of Antonín Ryska on Wikimedia.

2. Does My Automobile Have a MAP Sensor?

Instead of a MAP sensor, near modern vehicles use a mass air flow (MAF) sensor that the computer uses to summate air flow along with engine rpm.

Some vehicles come up equipped with both a MAP and MAF sensor, usually forced consecration systems like turbocharged and supercharged models.

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Sometimes, the MAP sensor is used to monitor EGR operation, and doubles as a back upwards to the MAF sensor.

If you need information regarding your vehicle, consult the repair manual for your particular make and model. You tin buy an cheap Haynes manual from Amazon. These manuals come up with procedures for many maintenance, troubleshooting and replacement component projects. And so the transmission practically pays for itself afterwards the first maintenance or repair project.

Circumspection: When Checking Voltages

Use the repair manual for your particular vehicle make and model for diagnostic value specifications.

Employ a scanner to download diagnostic trouble codes from your car computer.

Photo in the Public Domain

3. P0105 and Other MAP Problem Codes

Sometimes, a malfunction in the MAP sensor or its circuit will trigger the check engine light (CEL).

Scanning the estimator, yous may detect a P010X series of codes stored in retentiveness.

Here is a brief description of these codes:

• P0105: MAP sensor excursion malfunction.
• P0106: MAP sensor circuit, range or operation malfunction.
• P0107: Circuit, low input.
• P0108: MAP sensor excursion, high input.
• P0109: MAP sensor circuit, intermittent failure.

Other related codes include P0068 and P0069.

You can find a more detailed description of these codes in your vehicle repair manual or by searching on-line.

Carefully read the description of the code yous've found and what the potential mistake resulted from this code.

Remember that even though the code points to the potential trouble, the item circuit or component involved may not be at error. Instead, a related component may accept triggered the code.

For example, in many applications a leaking vacuum hose or a bad throttle position sensor (TPS) may cause a trouble code that points to a faulty MAP sensor.

Troubleshooting the sensor is the only fashion to decide whether the sensor or part is actually bad.

On some models, you just need to remove a couple of screws to get to the sensor.

Photo courtesy of Rich Niewiroski Jr. on Wikimedia

four. MAP Sensor Location

The MAP sensor is ordinarily located in a few central places around the upper engine bay area.

• Intake manifold. Under or near the throttle trunk; this is perhaps the most common place.
• Inner fender.
• Firewall.
• Air cleaner assembly.
• Under the dashboard.

The sensor may connect to the intake manifold with a vacuum hose or directly, by sitting on elevation of the intake manifold.

Caution: When Using a DMM

Always use a digital multimeter with a minimum 10 megaohms of impedance, to foreclose harm to sensitive electronic and electrical devices in your vehicle.

Apply a digital multimeter with at least 10 Megaohm impedance to troubleshoot the MAP sensor.

Photo courtesy of Andy / Andrew Fogg on Wikimedia

5. How to Test a MAP Sensor

When testing a MAP sensor, first make a preliminary check.

The sensor connects to the intake manifold with a rubber hose, depending on your particular application; otherwise it connects directly to intake.

When problems arise, information technology's more probable that the vacuum hose has failed. Within the engine compartment sensor and hose are exposed to loftier temperatures, potential contamination from oil and fuel, and vibration that can touch on their operation.

Cheque the vacuum hose for:

• kinks
• loose connections
• cracks
• swelling
• softening
• hardening

Then, cheque the sensor's body for damage and make sure the electrical connection is tight, make clean, and the wiring is adept.

Compare your readings to specifications listed in your vehicle repair manual.

Photograph in the Public Domain

six. Checking the MAP Sensor Reference Bespeak

The MAP sensor uses a three-wire connector. You need to identify the signal, reference, and ground wires using your vehicle repair manual.

Checking for reference voltage:

1. Plough the ignition key to the On position but don't first the engine. This will allow the calculator to supply a reference voltage to the MAP sensor.
2. Set up your multimeter to well-nigh 10V on the direct current (DCV) scale.

3. Backprobe the reference wire at the connector. The readout should show 5 volts or close to it.

   • If your voltage is lower, visually inspect the connector and wire betwixt the sensor and the PCM for impairment. You may need to measure out this voltage on the same wire but at the computer side.
     • If you still get a low voltage at the figurer side, and so you need to check the computer.
     • Otherwise, if the voltage rises to 5 volts, than there is a problem in the wire between the computer and sensor.
4. Turn off the ignition cardinal.

Checking for signal voltage:

1. Unplug the sensor's vacuum hose.
2. Connect a hand-held vacuum pump to the sensor, but don't apply vacuum to the sensor all the same.
3. Backprobe the signal on the electrical connector using the ruddy DMM probe. Connect the blackness DMM probe to ground using any metal surface on the engine or the battery negative postal service.
4. Turn the ignition switch to the On position, but don't outset the engine.
5. Your voltage reading should be betwixt 4.6 and 5 volts.
6. Utilize 5 in-Hg of vacuum to the sensor. The readout should be about 3.75 volts.
7. Now apply 20 in-Hg of vacuum to the sensor. The voltage should be about one volts.

Your readings may vary slightly, depending on altitude and electric current weather weather condition.

Note: On some repair manuals, you lot're asked to check resistance while applying vacuum to the sensor. Follow the instructions in your detail manual and compare your results to listed specifications.

The following table shows the estimate MAP sensor return-signal voltage driblet when a specific corporeality of vacuum is applied. Apply these values as a full general reference.

Too, lookout the video towards the terminate of this post that gives y'all a visual reference about troubleshooting an analog MAP sensor using a DMM and a hand-held vacuum pump.

MAP Sensor Voltage Drop Reference Tabular array

Vacuum	Voltage drop
5 in-Hg	0.7 to 1.0 Volts
10 in-Hg	one.three to i.9 Volts
xv in-Hg	2.0 to 2.8 Volts
20 in-Hg	3.0 to iii.viii Volts

You can use an oscilloscope or a DMM with a frequency part included to test a digital MAP sensor.

Photo in the Public Domain

7. Testing a Digital MAP Sensor

If your vehicle uses a digital MAP sensor, instead of an analog 1, you tin can also test it using a DMM that tin can measure out frequency signals.

1. First, set your multimeter to nearly 100 or 200 hertz.
2. Unplug the vacuum hose form the sensor and plug in a hand-held vacuum pump to the sensor'southward vacuum port.
3. Backprobe the signal and ground wires at the sensor electrical connector.
4. Plow the ignition key to the On position but don't kickoff the engine.
5. Brand a note of the voltage, duty cycle and frequency readings on your meter.

6. Now, utilize nearly eighteen in-Hg of vacuum to the sensor, and note the voltage, duty bike and frequency readings on your meter.

   • Your sensor should have about the same voltage and duty cycle readings in both tests.
   • Without vacuum applied, the sensor should take about 160 hertz.
   • With vacuum applied, the sensor should drop to near 100 hertz.

Consult your vehicle repair transmission for specifications.

On some models, you lot may need a Torx screwdriver or bit to remove the MAP sensor.

Photo in the Public Domain

viii. MAP Sensor Replacement

Replacing a MAP sensor is a straightforward operation. Sometimes the sensor is readily accessible and you can replace it in well-nigh five minutes or less; other times, you may demand to remove i or more than accessories to gain access to it.

Regardless, the following process volition aid you replace the sensor. If the sensor in your vehicle uses a vacuum hose, it's a adept thought to replace it forth with the sensor.

1. First, locate the sensor. You may detect information technology:

   • around the top of the intake manifold
   • about the firewall
   • sitting next to the throttle body or nether it
   • mounted on the tower on the well

   Consult your vehicle repair manual, if necessary,

2. Disconnect the negative battery cable and secure the cable away from the post.
3. Depending on the location of the sensor, you may demand to remove 1 or more than bolts or Torx screws.
4. Unplug the sensor electrical connector. The connector may exist securely locked. If so, depress the locking tab and and so unplug the connector.
5. Detach the vacuum hose from the sensor, if it has one.
6. Disassemble the vacuum hose from the other stop.
7. Use the old vacuum hose as a guide to trim the new one to proper length, if necessary.
8. Connect the new hose to the fitting on the intake manifold side, and the other cease to the new MAP sensor.
9. Plug in the sensor electric connector. Make certain the connector locks to the sensor.
10. Mount the new sensor in place.
11. Connect the negative battery cable to the bombardment postal service.

This article is authentic and true to the all-time of the author's knowledge. Content is for advisory or entertainment purposes only and does non substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: I have a 2000 One thousand Cherokee Limited four.7 2x2. Since I bought it, I'grand having the trouble of it dying while driving and leaving me stranded for 5 minutes to 5 hours. As mysterious equally it dies (no warning or sign or engine light), information technology'll start support and bulldoze commonly till the adjacent time. It seems worse in the summer as it's common cold here and she hasn't died in 18 days! Which is miraculous as it goes days with dying ii-8 times a mean solar day or get days without dying. Can you show me or tell me what to do!!?

Answer: This other post may help:

https://axleaddict.com/motorcar-repair/Why-My-Car-Stal...

Question: I have Suzuki XL7 2007. It was fine merely at a sure indicate the engine low-cal came on. My problem is that when I drive, information technology downshifts while stopping at a traffic light or sometimes delayed shifting response from lower gears while accelerating or sometimes fifty-fifty random shifting between gears. For example, it sticks in gear four and when I endeavor to downshift from that gear, information technology goes to gear 2. It skips gear 3. Could the PCM module or MAP to crusade my Suzuki to skip gears when downshifting?

Answer: Ordinarily, delay in shifting is acquired by the clutch for those specific gears. However, other bug can also atomic number 82 to this issue, like a leaking hydraulic excursion or a sticking spool valve in the valve body. Also, you may desire to try checking the vacuum. If it fluctuates or has wrong pressure, there could exist your problem. This other post may help:

https://axleaddict.com/auto-repair/Use-a-Vacuum-Ga...

Yous may need to bring the vehicle for testing to identify the cause of the problem.

Question: I have a 06 Altima that keeps giving a P0420 code for the oxygen sensor. I replaced both sensors and creepo position sensor, which we had a code. The crank code went away, the oxygen sensor will not. I previously replaced catalytic converter 2 times, then both oxygen sensors and code is nevertheless on for the 02 sensor. What could the P0420 code mean?

Respond: Code P0420 points to the downstream oxygen sensor. According to the code, the sensor is reading too much oxygen in the exhaust stream. There could exist a leak in the exhaust system, misfire, the faulty fuel injector (besides much fuel), faulty fuel pressure regulator (increased pressure), or even a fault in the downstream oxygen sensor circuit.

Question: We have a 08 Charger with a Hemi. We have replaced the fuel pump, throttle body, crankshaft sensor, and peddle associates. What else can we practise?

Answer: If y'all are having issues with fuel delivery or spark have the fuel or ignition arrangement tested. Information technology's not a skilful idea to replace components without troubleshooting the specific components.

This other post tin can help you beginning troubleshooting the fuel organisation:

https://axleaddict.com/automobile-repair/How-to-Test-a-F...

Check you accept a adept spark. If you haven't already, check for trouble codes, even if the check engine light is non coming on. At that place could exist pending codes that tin can assistance you lot figure out what component/system is giving you problems.

Question: I have a 2004 Contrivance Dakota. Engine light came on. Truck started to kind of spit and sputter. O2 codes came upwardly forth with a heat code. I replaced all 4 sensors. Information technology ran great. Now 2 months afterward it's doing the same affair. No one tin figure it out. I have been told the computer may be bad. Any ideas?

Answer: The engine might exist running in open loop because of the lawmaking and running rich. Bank check for foul spark plugs that might be causing misfires. If you still have the old ones, check those sensors for carbon buildup. There can exist a problem with the catalyst that might be affecting one or more O2 sensors. Likewise, the problem could be in the circuit to the heating element or the sensor themselves.

Question: When information technology's less than 25 degrees Fahrenheit, my 2022 Ford F250, fifty-fifty when completely warmed up, doesn't have whatsoever power until 2000 RPMs. And then it gets normal ability and pushes fuel similar normal once more. What could exist the crusade of this?

Respond: There could be a problem with a sensor. You may want to check the temperature sensor. It may have become lazy and giving inaccurate readings to the ECU and miscalculating fuel needs. Download trouble codes, even if the engine light is non on. A pending lawmaking may exist stored in memory that can help y'all hither.

Question: I have a 2004 Buick LeSabre. If my sensor has a crevice in it, does it necessarily mean information technology'south bad? I ask considering I just had to replace caput gaskets. Is information technology due to the sensor?

Answer: You can exam the sensor to make sure it's operating properly. If information technology already has a crack, information technology'south better to supervene upon it. The sensor only measures vacuum or intake force per unit area and it won't cause impairment to the caput gaskets.

Question: My 2002 Town and Country is showing a misfire in cylinders 1 and 4. It runs rough at idle, backfires under load or acceleration, surges when trying to concur at 4000 RPM and park. Is the MAP at error for my Boondocks and Country'south cylinder problems, or is something else going on?

Respond: There could be several reasons for a misfire. Your misfire is located on the 1 and 4 cylinders; this can brand it easier to locate the fault. Check out this other post. it may assistance you lot find the source of the misfire:

https://axleaddict.com/auto-repair/Engine-Misfires...

Question: I have a 1989 Buick Le Sabre and accept replaced my MAP twice. It runs good a few weeks and and then I have bug once more with symptoms of stalling and low power. I'grand okay if I keep my human foot in the gas at all times. The only lawmaking that comes up is the MAP sensor. Any ideas why my sensor keeps failing? Or what else should I await at?

Answer: The problem might be in the connector or excursion for the MAP sensor. You may need the repair transmission for your model to identify wires. Cheque the vacuum hose every bit well. These other posts may aid too:

https://axleaddict.com/auto-repair/Why-My-Motorcar-Stal...

https://axleaddict.com/motorcar-repair/What-Causes-Low...

Question: Is in that location a reset button you need to practice when putting in a new MAP sensor on a 2022 Ford Fusion set to shut off the check engine light?

Answer: On some models, it's possible to disconnect the battery to turn off the check engine light. But I believe yous need to erase the code in social club to reset the light using a scanner. Otherwise, information technology'll continue coming dorsum, even if you disconnect the battery. Try Autozone get-go. If not, cease past a local shop. They'll charge you though. Hope this helps.

Question: I have a dodge dart 2022 gt, it turns off sometimes running and in that location comes a time where it does non get-go. Twice he has turned on the code p2172 and replaced the part of the throttle organisation and continues with the aforementioned error?

Answer: Probably the idle air control (IAC) motor is getting stuck, allowing too much air to into the system. Brand sure the throttle plate is not getting stuck either. This other post may help here:

https://axleaddict.com/auto-repair/Why-My-Car-Stal...

Question: Where is the MAP sensor located?

Answer: It depends on your particular model, but look at a location, commonly, in the upper area of the engine compartment: virtually the strut belfry, intake manifold, throttle body, even well-nigh the headlight assembly. Sometimes you need to remove the air cleaner associates to gain access to it. The auto parts person at your local area may exist able to tell you the location in your particular model.

© 2022 Dan Ferrell

Source: https://axleaddict.com/auto-repair/Bad-MAP-Sensor-Symptoms-and-Testing

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