Neon L4-2.0L SOHC (1995)
high, and a higher voltage signal (3.9 to 4.8 volts) at deep throttle when the manifold vacuum is low. The MAP receives a 5-volt supply from PCM
cavity 43; voltage may vary from 4.8 to 5.1 volts. The sensor ground is provided by PCM cavity 51.
POSSIBLE CAUSES:
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Restricted or leaking vacuum/pressure to MAP sensor
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Ice in sensor or passage
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Failed sensor
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Failed PCM
No 5 Volts to MAP Sensor
NAME OF CODE:
No 5 Volts to MAP Sensor
WHEN MONITORED:
With the ignition OFF.
SET CONDITION:
The MAP sensor signal voltage goes below 1.96 volts.
THEORY OF OPERATION:
This sensor measures manifold absolute pressure and ambient barometric pressure within the manifold. It provides a 0 to 5 volt signal to PCM
cavity 36. The MAP sensor puts out a low voltage signal (0.5 to 1.8 volts) at idle when manifold vacuum is high, and a higher voltage signal (3.9
to 4.8 volts) at deep throttle when the manifold vacuum is low.
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The MAP receives a 5 volt supply from PCM cavity 61; voltage may vary from 4.8 to 5.1 volts.
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The sensor ground is provided by PCM cavity 43.
POSSIBLE CAUSES:
-
Open 5 volt supply
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MAP sensor failure
TPS Voltage Does Not Agree With MAP
NAME OF CODE:
TPS Voltage Does Not Agree with MAP
WHEN MONITORED:
With the engine running.
SET CONDITION:
The powertrain control module (PCM) performs two separate tests on the Throttle Position (TP) sensor: the high voltage test and the low voltage
test. The high voltage test is performed when the engine speed is very low and manifold vacuum is very high; these conditions indicate that the
throttle plate must be nearly closed, in which case the TP sensor signal voltage output must be low. The low voltage test is performed when the
engine speed is above 25 MPH and manifold vacuum is low; these conditions indicate that the throttle plate is open, in which case the TP sensor
signal must be high. If the proper TP sensor voltage is not present when the two conditions are met, the code will set after 2.8 seconds.
THEORY OF OPERATION:
The TP sensor contains a potentiometer that is operated by the throttle blade shaft. As a throttle plate rotates, the TP sensor provides a variable 0
to 5-volt signal to PCM cavity 10. The voltage is directly proportional to throttle angle. When the throttle plate is at rest, the voltage is low. When
the throttle is fully open, the voltage is high. With this signal, the PCM can determine precise throttle position under all operating conditions. The
TP sensor receives a 5-volt supply from PCM cavity 43. The sensor ground is provided by PCM cavity 51.
POSSIBLE CAUSES:
-
Failed powertrain control module
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TP sensor failure
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Sensor miswired
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Mechanical failure
