Chrysler neon 1997 Service Manual page 1335

14 - 48 FUEL SYSTEM
DIAGNOSIS AND TESTING (Continued)
ENGINE COOLANT TEMPERATURE SENSOR
(1) With the key off, disconnect wire harness con-
nector from coolant temperature sensor (Fig. 78) or
(Fig. 79).
Fig. 78 Engine Coolant Temperature Sensor
Location—SOHC
Fig. 79 Engine Coolant Temperature Sensor
Location—DOHC
(2) Connect a high input impedance (digital) volt-
ohmmeter to terminals A and B (Fig. 80). The ohm-
meter should read as follows:
• Engine/Sensor at normal operating temperature
around 200°F should read approximately 700 to
1,000 ohms.
• Engine/Sensor at room temperature around 70°F
ohmmeter should read approximately 7,000 to 13,000
ohms.
(3) Test the resistance of the wire harness between
the PCM 60-way connector terminal 28 and the sen-
sor harness connector. Also check for continuity
between PCM 60-way connector terminal 51 and the
sensor harness connector. Refer to Group 8W, Wiring
diagrams for circuit information. If the resistance is
Fig. 80 Engine Coolant Temperature Sensor
greater than 1 ohm, repair the wire harness as nec-
essary.
HEATED OXYGEN SENSOR
Use an ohmmeter to test the heating element of
the oxygen sensors. Disconnect the electrical connec-
tor from each oxygen sensor. The white wires in the
sensor connector are the power and ground circuits
for the heater. Connect the ohmmeter test leads to
terminals of the white wires in the heated oxygen
sensor connector. Replace the heated oxygen sensor if
the resistance is not between 4 and 7 ohms.
IDLE AIR CONTROL (IAC) MOTOR TEST
To preform a complete test of IAC motor and its
circuitry, refer to DRB scan tool and the appropriate
Powertrain Diagnostics Procedures manual.
KNOCK SENSOR
The knock sensor can be tested with a digital volt-
meter. Sensor output should be between 80 mV and 4
volts with the engine running between 576 and 2208
rpm. If the output falls outside of this range a DTC
will be set.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
To perform a complete test of the MAP sensor and
its circuitry, refer to the DRB scan tool and appropri-
ate Powertrain Diagnostics Procedures manual. To
test the MAP sensor only, refer to the following:
CAUTION: When testing the MAP sensor, be sure
that the harness wires are not damaged by the test
meter probes.
(1) Test the MAP sensor output voltage at the
MAP sensor connector between terminals 1 and 4
(Fig. 81). With the ignition switch ON and the engine
not running, output voltage should be 4 to 5 volts.
PL