CODE 22 ENGINE LIGHT ON HELP

[ramair4ta]

recently, my engine light has been going on and off. i purchased a code scanner. code #22 comes up.
i know its a BAP sensor code. i noticed my lean/rich meter (digital meter with the bars) is not cycling from lean to rich like it was. it stays down at the lean side and that's when the light came on. when i run the engine running test, the idle goes up and the light goes off and the meter (lean/rich) reads and cycles normal.
what would be your suggestion on repair or fixing the engine light?

 

[jrichker]

Fix the code 22 and the check engine light should go off. Code 22 puts the computer in limp mode, which reduces performance & economy.

Code 22 MAP (vacuum) or BARO signal out of range. The MAP or BARO sensor is pretty much the same sensor for both Mass Air & Speed Density cars. The main difference is where it is connected. Mass Air cars vent it to the atmosphere, while Speed Density cars connect it to the intake manifold vacuum. Its purpose is to help set a baseline for the air/fuel mixture by sensing changes in barometric pressure. The MAP or BAP sensor puts out a 5 volt square wave that changes frequency with variations in atmospheric pressure. The base is 154 HZ at 29.92" of mercury - dry sunny day at sea level, about 68-72 degrees. You need an oscilloscope or frequency meter to measure it. There a very few DVM with a price tag under $40 that will measure frequency, but there are some out there.

The MAP/BARO sensor is mounted on the firewall behind the upper manifold.

Baro or MAP test using frequency meter - run the test key on engine off. The noise from the ignition system will likely upset the frequency meter. I used a 10 x oscilloscope probe connected from the frequency meter to the MAP/BAP to reduce the jitter in the meter's readout.

If it is defective, your air/fuel ratio will be off and the car’s performance & emissions will suffer

Some basic checks you can make to be sure that the sensor is getting power & ground:
Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.
Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the black/white wire and the negative battery cable. It should be less than 1.5 ohm.

The following power on check requires you to turn the ignition switch to the Run position.
Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or EGR sensors. Use the black/white wire for the ground for the DVM.

 

[ramair4ta]

thanks for the info. i will test everything you mentioned shortly. like i mentioned, the lean/rich gauge was not cycling as normal while driving. as soon as the gauge stopped cycling, the light came on, leading me to believe a sensor went. the code 22 came up which as you mentioned, controls air fuel mixture. the car idles fine, runs fine (didnt get into the boost), but it may be running lean as the gauge only shows to bars above lean, where as it used to cycle top to bottom while driving.
if all checks out with the dvm, then i take it the sensor is bad at this point?

im new here and the car is a 1993 coupe electric red with black interior. S/C, 4 wheel disc conversion, too much to type thats been performed at Steeda Motorsports in Florida.

i will let you know what i find with the testing of the wires.

 

[ramair4ta]

OK testing results on wires. all the resistances to all the wires check out ok.
i have 5 volts on the tps and egr sensor wires. i do not have 5 volts on the orange/white wire on the BARO sensor connector with the ignition switch to the run position. whats the verdict?

 

[jrichker]

Try taking the measurements with the MAP connecter disconnected from the sensor. Sometimes probing them from the rear doesn't make good contact. Inspect the connector contacts and wiring - look for loose, corroded or damaged pins and wiring.

Recheck your reading using the battery negative terminal for ground. . If you still don't get the 5 volts=/-.5 vol, the wire is broken inside the harness.

 

[ramair4ta]

i was going to recheck it again to be sure. i disconnected and rechecked. everything has 5 volts. 4.96 4.99 4.99 so am i at a bad sensor?

thanks for the quick replies. its going to a show this weekend and i really didnt want the light on for the show.

 

[jrichker]

i was going to recheck it again to be sure. i disconnected and rechecked. everything has 5 volts. 4.96 4.99 4.99 so am i at a bad sensor?

thanks for the quick replies. its going to a show this weekend and i really didnt want the light on for the show.

If all the voltages are good, the sensor is all there is left to be suspect. Try the junkyard first for a replacement unit All the reman units are just junkyard items that have passed a quick test.

 

[ramair4ta]

CODE 22 LIGHT PUT OUT! PROBLEM SOLVED. NEW BAP SENSOR INSTALLED, CODES CLEAR, AIR/FUEL GAUGE RESUMED WORKING PROPERLY. LOOKS LIKE EVERYTHING IS WORKING CORRECTLY AFTER A NICE CRUISE TODAY. THANKS AGAIN FOR THE HELP AND ADVICE. FEELS GOOD BEING ABLE GET INTO THE 475RWHP AGAIN NOT WORRYING ABOUT IT RUNNING LEAN.