car dies while cruising on the freeway and still code 22

old_blue

15 Year Member
Nov 3, 2003
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I posted a while back that I had a code 22 when I pulled them. I replaced the bap and checked all the resistance through the wires which all checked out. Car ran fine then

fast forward to now. After the car warms up I will be cruising on the freeway 65-75mph when the car just dies. But since it is still rolling and in gear the car will start again (like a push start) and then it runs fine. I am not sure if this is related to code 22 or not or something totally different. I was thinking maybe a bad tps but when I ran the tests given by jrichter it all came out fine. should I still replace it???

kinda fustrating as it runs great otherwise and has only done this three times.

any suggestions would be great.thanks
 
This is probably a repeat of some information I posted for your problem the first time, but just in case...


Pay close attention to the voltage checks at the end of the tech note. Clear the codes and dump them again immediately after the engine dies. If there wasn't a code 22 before and now there is, there may still be problems in the circuit, it's wiring or MAP sensor. What I suspect is a loss of the VREF voltage that powers the MAP, TPS and EGR sensors. The MAP sensor suddenly failing probably won't shut the engine down, but losing all 3 sensors could cause a sudden shutdown. A voltmeter used to monitor the VREF at the MAP sensor might be helpful in eliminating this as a possible problem. You would need to connect it up and leave it connected to observe what happens to VREF when the engine cuts off.


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's 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.
 
here is the original post with the results I got from the above tests. I will check them again this weekend to make sure I ge tthe same results from the test.
http://forums.stangnet.com/759463-got-home-now-need-help-codes-black-smoke.html

Today I went out and the car wouldnt start. I noticed there was a lot of corrosion on the battery. I cleaned the terminals and cables with a wire brush and now it fires up all the time. I wouldnt think this would have been the problem with it dying as it would just run off the alternator once it was started. any ideas there??