P1296 No 5 Volts To MAP Sensor

Hi, see the picture below. Before replacing the MAP sensor, check the vacuum line for leaks. If the vacuum is good and you have a voltmeter, check the signals. With the key on, there should be 5 volts DC between the outer terminals of the connector. Don't take it off--just stick your meter probes in the back of the connector until they touch the bare wires. If you don't have 5 volts there, the problem is not the sensor--it's the wiring or the computer. If you do have 5 volts there, check the voltage from the white wire to either of the other 2. That voltage should be between 1 and 5 volts, and it should change a lot when you start the engine. If it doesn't change at least a couple of volts, the sensor is probably bad. Please let me know if you have questions, and thanks for using FixYa.

More likely the MAP sensor. A new sensor is $65, so I recommend you test it to see if it's bad. Test procedures are pasted below. Please let me know if it passes the tests or if you have any questions, and thanks for using FixYa.

OPERATIONThe PCM supplies 5 volts to the Manifold Absolute Pressure (MAP) sensor. The MAP sensor converts what it reads as the amount of intake manifold pressure into a return signal. The PCM monitors the MAP sensor output voltage. As vacuum increases in the intake manifold, the MAP sensor voltage decreases proportionately. Also, as vacuum decreases, the MAP sensor voltage increases proportionately.
During engine cranking, before the engine starts running, the PCM determines atmospheric air pressure from the MAP sensor voltage. While the engine operates, the PCM determines the intake manifold pressure from the MAP sensor voltage.
Based on MAP sensor voltage and inputs from other sensors, the PCM adjusts spark advance and the air/fuel mixture.
TESTING

Fig. Fig. 1: Manifold absolute pressure (MAP) sensor wiring schematic-1993-95 models

Fig. Fig. 2: Manifold absolute pressure (MAP) sensor connector terminal pin locations-1993-95 models


Before testing any electrical component, inspect the wiring and connectors for damage. Also wiggle the connectors to ensure a that they are firmly engaged. When testing the sensor, use a high input impedance digital volt-ohmmeter. Insert the tester leads through the back of the connector. Do not disconnect the electrical harness.

1. Inspect the vacuum hose connections at the sensor and throttle body. Repair or replace the hoses, if any hoses are cracking or vacuum is leaking.

For the following step, do not unplug the sensor connector-it must stay plugged in.

1. Make sure that the sensor wiring connector is fully inserted into the sensor (loose connections can create trouble codes). Check the MAP sensor output voltage by inserting the negative lead of a voltmeter into the back of terminal 2 and the positive test leads through the back of the harness connector terminal 3 (as marked on the sensor body). Refer to the accompanying wiring illustration. With the ignition switch in the ON position and the engine OFF , the output voltage should be 4-5 volts.
2. Start the engine and allow to idle at normal operating temperature. The output voltage should drop to 1.5-2.1 volts.
3. Test the PCM terminal 36 (1993-95 models), and terminal 1 (1996-97 models) for the same voltage described above to verify the wire harness condition. Repair the wiring harness if the voltage is not the same.
4. Test the MAP sensor supply voltage at the sensor connection terminal 2 and 1 with the ignition ON . The voltage should be 5 volts. Check the supply voltage at terminal 61 of the PCM. This should also be 5 volts.
5. Using an ohmmeter, test the MAP sensor ground circuit at the sensor connection terminal 1 and at the PCM terminal 43 (1993-95 models), terminal 4 (1996-97 models). Repair the wire harness for an open circuit if infinite resistance is detected.

REMOVAL & INSTALLATION

Fig. Fig. 6: On the 3.5L engine, the MAP sensor is threaded into the left side of the intake manifold plenum

The MAP sensor is located in the rear of the intake manifold plenum on the 3.3L engine. On the 3.5L engine, the MAP sensor is threaded into the left side of the intake manifold plenum.

1. Disconnect the negative battery cable.
2. Unplug the electrical connector from the sensor.
3. Remove the MAP sensor mounting screws.
4. Remove the sensor from the vehicle.

To install:

1. Install the MAP sensor into its position and secure in place with the mounting screws. Tighten the screws to 90 inch lbs. (10 Nm), then rotate it to a horizontal position.
2. Plug the electrical connector back into the sensor. Make certain that the connector is clean and snug fitting.
3. Connect the negative battery cable.

p105b ???? What scan tool did you use to pull this code ?DTC P0105 is the correct DTC. Where do you people learn this stuff .I have 7-8 g/s vacuum??? What the heck is this ?? The only thing you'd see Grams a second on would be a mass air flow sensor , not the map sensor . Vacuum to the map sensor would be manifold vacuum . 18 - 22 at idle. MAP Sensor Eng 1, 2, 3
Volts
0.94-2.0 volts Varies with altitude
Dirty throttle bore ,plate ,EGR valve sticking open a little .
The PCM calculates a predicted value for the MAP sensor based on throttle position (TP) and engine speed. The PCM then compares the predicted value to the actual MAP sensor signal. If the PCM detects that the MAP sensor signal is not within the predicted range, DTC P0105 sets.

034 Engine Misfire Vacuum Leak Test

Hello jlockhart8: My name is Roger and I will help you. The barometric sensor is built into the MAP sensor. You will find it located on the top of the motor just to the left of the throttle body. Should you need further help lease just ask. Please rate the answer. Thank You fo using Fix Ya. Roger

Hello! The PERCUS...E...Code is an Electronic Control Module (ECM) programming error or failure...The grounding may be at fault...Using an ohm meter set on X10 scale...Read from center of negative battery post to bare metal on chassis and then to engine block...Should read very near zero ohms...If these readings are OK...The ECM needs to be re-flashed (reload software) at a dealership.

MAP reading across wire colors Black/White (+) and Black/Green (-) at idle should be 1.1 volts...(.99 is a correct reading)...Throttle up and voltage increases to 3.75 volts w/o erratic movement...This indicates MAP is OK...

Guru.............Saailer

I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

Check for vacuum leaks this will set the code also. there are different resistance values for the map at different altitudes. you will have to get these to check the map

This code means that there is
no 5 volt to map sensor.

The M.A.P. sensor is located on the upper intake manifold plenum. It has a plug with 3 wires connected to it, and a vacuum hose connected to it. to chek the sensor you'll need a volt meter. you can insert the positive lead into the backside of the terminal of the light green wire (with the plug still plugged into the sensor). Put the negative lead from the volt meter and ground it to a solid chassis ground. Turn the key to the on position (DO NOT START THE ENGINE). Your voltage should read 4.0 to 5.0 volts. Now start the engine. at idle your voltage should read 0.5 to 2.0 volts. If your volts read in those ranges your map sensor is good.

i had the same problem with my fiero the ignition module quits when it gets hot.

MAP enhancers usually wont do the trick for long - the computer will learn the adjustment to the MAF and overide within a day or so usually less than a few minutes.

The computer is best altered using an EFIE to adjust the O2 sensor(s), usually adding between .2 and .3 volts to the O2 sensor signals does the trick - each combo of the HHO and car is slightly different - you have to play with it to find your best setting. You only need to alter the signal on the O2 sensors ahead of the cats as they are the ones the computer uses to adjust the fuel.