Neon L4-2.0L DOHC (1996)
Voltage Signal: Description and Operation
Related Trouble Codes and Set Conditions
Charging System Voltage Too Low
Name of Code:
Charging System Voltage Too Low
When Monitored:
With the ignition key on and the engine running above 1,500 RPM.
Set Condition:
With no other charging system codes set. The battery sensed voltage is 1 volt below the charging goal for 25 seconds. The PCM senses the battery
voltage, turns off the field driver and senses the battery voltage again. If the voltages are the same this code is set.
Theory of Operation:
The PCM tries to maintain a system voltage between 12.9 volts and 15.0 volts. The voltage determined by the PCM as the final goal for the
charging system is called control voltage. This control voltage is determined from the battery temp sensor (ambient sensor). The control voltage is
compared to the sensed voltage continuously during running. If the sensed voltage is less than the control voltage the PCM will supply more
ground to the field circuit. If the sensed voltage is more than the control voltage the PCM will supply less ground to the field circuit.
Possible Causes:
-
Defects in generator drive belt or adjustment
-
High resistance between battery B(+) and generator B(+)
-
High resistance between battery B(-) and generator B(-)
-
PCM failure
-
Connector terminals
-
Connector wires
-
High field circuit resistance (in generator)
Generator Field Not Switching Properly
Name of Code:
Generator Field Not Switching Properly
When Monitored:
With the ignition key on and the engine running.
Set Condition:
When the PCM tries to regulate the generator field with no result during monitoring.
Theory of Operation:
The PCM tries to maintain a system voltage between 12.9 volts and 15.0 volts. The voltage determined by the PCM as the final goal for the
charging system is called "control voltage". This control voltage is determined from the battery temp sensor (ambient sensor). The control voltage
is compared to the sensed voltage continuously during running. If the sensed voltage is less than the control voltage, the PCM will supply more
ground to the field circuit. If the sensed voltage is more than the control voltage, the PCM will supply less ground to the field circuit.
Possible Causes:
-
Field driver circuit open or shorted
-
Generator internal open or short
-
PCM failed
