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p1492 cant find the cause

995speed

NAXJA Forum User
Location
Ridgefield
99 XJ 4.0 AX15

Gas Gauge does not work and check engine light is on.
The code is p1492 ambient/ battery temp sensor voltage to high. The Alternator is not charging the batter. I replaced the battery temp sensor r the battery and the alternator. And i still have the same problem. I am at a loss help please.
 
99 XJ 4.0 AX15

Gas Gauge does not work and check engine light is on.
The code is p1492 ambient/ battery temp sensor voltage to high. The Alternator is not charging the batter. I replaced the battery temp sensor r the battery and the alternator. And i still have the same problem. I am at a loss help please.

Is it a "check engine" or a "check GAUGES" light?
 
Disconnect the ambient/ battery temp sensor. Start the engine. Measure the DC voltage across the sensor connector. It should be less than 5.5 dc volts. post up what you get for a measurement.
 
Disconnect the ambient/ battery temp sensor. Start the engine. Measure the DC voltage across the sensor connector. It should be less than 5.5 dc volts. post up what you get for a measurement.

Hi guys. Just tested the connectors at the ambient air temp connector getting 4.95 volts at the batt temp connector I'm getting 2.85 volts. I also noticed my over head console the DTE reading reads OC what is that over charge open circuit??
 
OC in the display means open circuit. The 99 xj is known for instrument cluster connection problems... so your fuel guage not working and the DTE "distance to empty" over head console readout problem must be related to each other. Is the console displaying ambient air temp correctly?

There are many threads here about the instrument cluster. They mostly describe a bad connection on the back of the instrument cluster. Fixing this problem may be important to be sure we are getting the right info from the PCM.

2.85 volts at the batt temp connector seems low... I am going to research it and get back to you.
 
Well you guys are never going to believe this. A few months back my fully lubricated transfer case locked up on me on the highway. Snapped the driveshaft like a twig and and the dticeshaft hit my bell housing cracking the bell housing and one of the ears of the motor. Which was causing the transmission to tilt over to one side
In the interest of time and Money I put in a salvage yard motor with 120k on it. I did the swap at the technical school I go to Porter and chester I had a fellow student or two helping me out somewhere along the way someone broke the clips to the harness connector towards the back of the motor a few months of daily bumps and etc of driving it managed to become slightly disconnected so there was no full contact after fully connecting and electric taping the two ends together everything started working again....
 
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