Need Urgent Help with MAP Problem!

jacob03kj · **Joined:** Mon Apr 18, 2011 10:47 pm **Posts:** 34

Hi all,
thanks in advance for any and all assistance. Tonight after driving my Jeep all day, perfectly fine, I got in it to drive up to the store and it barely wanted to start. It stalled 3 times, then ran extremely rough with plenty of backfiring, surging, and bogging, so I parked it. I drove it less than 1 mile. It is throwing a P0108 code, for MAP voltage too high. I disconnected the battery for over an hour, tried it again, no luck. So I pulled the MAP sensor harness and checked the 3 pins for voltage. The leftmost pin has 5.1volts with the ignition in the on position with the engine off, the center 0 volts, and the rightmost also at 5.1 volts. Before I drop $50 on a new sensor, does it sound like a new sensor will fix it? Could it be the PCM if the PCM is giving off the correct voltage? Thanks and please let me know if I am blanking on anything else to check!
-Jacob

jacob03kj · **Joined:** Mon Apr 18, 2011 10:47 pm **Posts:** 34

bump? Please!

papaindigo · **Posted:** Fri Aug 30, 2013 1:58 pm

Gasser or CRD? If CRD best post on CRD section. Offhand I don't have an answer though.

jacob03kj · **Joined:** Mon Apr 18, 2011 10:47 pm **Posts:** 34

gas, sorry forgot I removed my signature with the KJ's details. 2003 KJ 3.7 limited.

tjkj2002 · **Posted:** Fri Aug 30, 2013 8:19 pm

One wire is ground,one is the 5 volt reference signal from the PCM,and the last one is signal voltage from the sensor with the key on/engine off(and running).

If you tested the voltages with the connector still plugged into the MAP sensor and the key on a new MAP sensor should fix it.If that connector was unplugged you may have other issues like a bad PCM or wiring.

jacob03kj · **Joined:** Mon Apr 18, 2011 10:47 pm **Posts:** 34

I tested it with the connector unplugged, I will probe it later and see what it reads then. Thanks a million. I will post a report in about 2 hours. I will check the signal wire voltage vs the output wire voltage.

jacob03kj · **Joined:** Mon Apr 18, 2011 10:47 pm **Posts:** 34

Well I apologize that it took so long to get back. I had to make an unscheduled trip out of town (in a different car of course). I have not physically probed the MAP sensor harness for voltages, however, I did check the MAP readings via my Scangauge II, and it shows a reading of 15.2 (not sure what unit that is) no matter what RPM the jeep is at. In my Nissan Frontier it idles around 4.8 and at high rpm is around 1.6. I don't know the unit, or if the numbers very by vehicle, but in any sense the reading does not change with RPM.

jacob03kj · **Joined:** Mon Apr 18, 2011 10:47 pm **Posts:** 34

OK, so I physically probed each of the three wires on the MAP sensor with the connector plugged in. I had someone start the Jeep and vary the throttle from idle to 3000 RPM while the engine was still relatively cold (in case that makes a difference). The voltage of each wire stayed around 5.1V with a +/- 0.09V variance with RPM, which is insignificant. I am not sure which wire is the constant 5V input, but since neither wire ever changed voltage with RPM, I am thinking (and praying) it is only a bad sensor. I am going to pick up a new one now, and will report back if I can get one installed today. Thanks everyone!

jacob03kj · **Joined:** Mon Apr 18, 2011 10:47 pm **Posts:** 34

I can't get a Mopar MAP sensor today, I will get one early tomorrow morning.

jacob03kj · **Joined:** Mon Apr 18, 2011 10:47 pm **Posts:** 34

A new MAP sensor fixed it. Thanks everyone especially TJKJ!

tjkj2002 · **Posted:** Tue Sep 03, 2013 6:16 pm

jacob03kj wrote:

A new MAP sensor fixed it. Thanks everyone especially TJKJ!

Glad you got it fixed and was indeed only a bad sensor.Without actually being there and testing myself I could only do a "best guess' from past experiances.

Need Urgent Help with MAP Problem!

Who is online