The most likely cause of Fiat 1500 P348B code being stored is a defective automatic transmission cooler control valve or valve position sensor. Other causes may include corroded, open, or shorted wiring or connectors, a loose control module ground strap, or broken ground wire.
Common Symptoms For Fiat 1500 P348B
Repair or replace system circuits/connectors as required and retest the system to ensure that repairs were successful. Using the manufacturer's wiring diagram for the input/output speed sensor, test all related circuits and sensors for resistance and continuity and compare your findings with manufacturer's specifications
If the resistance level does not decrease with heat and increase as it cools, replace the sensor. If everything has checked out thus far, turn the key to the "ON" position and test for the presence of a voltage (and a ground signal) at the exhaust gas temperature/pressure (or heated oxygen) sensor electrical connector
The exhaust gas temperature sensor is used in diesel engines, gasoline burning engines, and even turbocharged engines
If the fuel shutoff switch and all system circuitry checks out, suspect a defective PCM (or other related controller)
Ignition System Or Misfire
TP Sensor Learn Not Complete
TFP Valve Position Switch-Drive Without Drive Ratio
Fiat 1500 P348B Troubleshooting
Broken engine mountings can cause banging and graunching noises. There are two main types of mounting those centrally placed close to the bottom of the block and those higher up the block which mount on to the inner wings or chassis members. Fiat 1500 P348B OBD2 reports a sensor fault, replacement of the sensor is unlikely to resolve the underlying problem. The fault is most likely to be caused by the systems that the sensor is monitoring, but might even be caused by the wiring to the sensor itself.
How to turn off Fiat 1500 P348B check engine light ?
There are two ways to turn off the check engine light:
A repair technician can do so once repairs have been made.
The OBD II can automatically turn it off when it fails to detect the problem after several diagnostic cycles.