Neon L4-2.0L DOHC (1996)
Throttle Position Sensor: Description and Operation
Related Trouble Codes & Set Conditions
Throttle Position Sensor Voltage High
Name of Code:
Throttle Position Sensor Voltage High
When Monitored:
With the ignition on.
Set Condition:
TP sensor voltage at PCM cavity 35 goes above 4.5 volts for 0.704 seconds.
Theory of Operation:
The throttle position sensor contains a potentiometer that is operated by the throttle blade shaft. As the throttle plate rotates, the TP sensor
provides a variable 0 to 5-volt signal to PCM cavity 35. 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 61. The sensor ground is provided by PCM cavity 43.
Possible Causes:
-
Sensor signal circuit open
-
Throttle position sensor failure
-
Sensor ground circuit open
-
PCM failure
-
Connector terminals
-
Connector wires
Throttle Position Sensor Voltage Low
NAME OF CODE:
Throttle Position Sensor Voltage Low
WHEN MONITORED:
With the ignition ON.
SET CONDITION:
The Throttle Position (TP) sensor voltage at Powertrain Control Module (PCM) cavity 35 goes below 0.2 volt for 0.704 seconds, or MPH is
above 20, RPM is above 1500, and vacuum is below 2" with TP sensor voltage less than 0.5 volt for 0.704 seconds.
THEORY OF OPERATION:
The throttle position sensor contains a potentiometer that is operated by the throttle blade shaft. As the 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 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 61. The sensor ground is provided by PCM cavity 43.
POSSIBLE CAUSES:
-
Sensor signal circuit shorted to ground
-
Throttle position sensor failure
-
Loss of 5-volt supply
TPS Voltage Does Not Agree With MAP
Name of Code:
TPS Voltage Does Not Agree with MAP
When Monitored:
With the engine running and no MAP sensor or TP sensor trouble codes.
Set Condition:
The powertrain control module (PCM) performs two separate tests on the 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 4 continuous seconds.
