Eclipse L4-1795cc 1.8L SOHC (1990)
1. Disconnect the motor position sensor connector, and connect the special test harness (MD998464) to the MPS connector side.
NOTE: Do not connect the special tool to the ECU harness side of the connector.
2. Connect an ohmmeter to terminals 1 (black clip on test harness) and 3 (white clip) of the motor position sensor connector.
Resistance Value:
4k - 6k Ohms
3. Disconnect the ISC servo connector. Connect the test harness to the sensor side.
4. Connect an ohmmeter to terminals 1 (black clip) and 2 (red clip) of the motor position sensor connector.
5. Connect a 6 VOLT DC power supply the the ISC connector terminals 1 and 2. This will extend or retract the servo depending upon the polarity of
the power connection.
CAUTION: Do not apply more than 6 Volts DC to the ISC motor. Application of more than 6 Volts can cause locking of the motor gears, and
damage to the motor.
6. Measure the resistance of the sensor as it is extended and retracted. There should be a smooth increase in resistance as the servo extends and a
smooth decrease in resistance as the servo retracts. If the reading is not smooth the assembly should be replaced.
HARNESS TEST
1. Disconnect the ISC connector and turn the key to the ON position.
2. Using a Voltmeter, measure the power supply Voltage between the harness connector terminals 3 and ground and 4 and ground.
Voltage:
4.8 - 5.2 Volts.
3. Check for continuity of the ground circuit, between the harness connector terminal 1 and ground.
Continuity: Should exist.
4. Turn off the ignition and disconnect the ECU connector. Check for continuity (short) to ground between the engine control unit harness connector
terminal 17 and the motor position sensor harness connector terminal 2.
Continuity: Should not exist.
5. Check for continuity between the engine control unit harness connector terminal 17 and the motor position sensor harness connector terminal 2.
Continuity: Should exist.
If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, clear
the trouble codes and road test the vehicle to confirm that the repair has corrected the problem and the code doesn't return.
If the same trouble code reoccurs, it is possible that there is an intermittent failure of the component or the ECU. Check for looseness at all harness
junctions and test for an intermittent failure.
