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MAP Sensor Fault Code

comanche91

NAXJA Forum User
Every once in awhile I check for fault codes on my 91 OBDI MJ using the ON/OF key. There have never been any, until today. I got a 12 (Battery or power to the ECM disconnected in the last 50 key cycles), 14 (MAP sensor voltage too high or low. Check circuit and sensor), 34 (Fault in cruise control circuit), and the closing 55. I'm not concerned with the 12 or even the 34 (do not have cruise), but do not understand the 14. I checked the MAP 5V supply (good), the MAP output at idle (2.1V, good), and the sensor ground point (good).

The vehicle runs fine. I ordered an new MAP anyhow and will see how it goes. Is the norm that a new MAP sensor will kill the code 14, and can the cruise control code 34 somehow be related to the MAP 14? Thanks.
 
Thanks for the reply jp. The new MAP did nothing as I suspected it would. I have a Unichip on my stroker that massages the MAP output, but I took the Unichip out of the circuit using the bypass plug and still have the 14 fault.

Also, I think my torque converter isn't locking up since while cruising at 65MPH now it's running about 300 RPM higher than before. I ohmed out the AW4 solenoids, all three are at 4.5 ohms, so next I'll remove the speed sensor and see if the reed switch is opening/closing as it should. Hope it's not the TCU. I still think the MAP 14 and cruise 34 faults are related.
 
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