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Electronic Control System Gas Plus Engines – 019-039   Engine Position Sensor (EPS) Circuit

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Inspect for Reuse

 TOC

Inspect the engine harness and sensor connector pins.

Disconnect the engine position sensor (EPS) and electronic control module (ECM) connectors.

Inspect the engine harness and engine position sensor connector pins for the following:

  • Loose connector
  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Dirt or debris in or on the connector pins
  • Connector shell broken
  • Wire insulation damage
  • Damaged connector locking tab.

Refer to the circuit diagram or wiring diagram for connector pin identification.

For general inspection techniques, refer to Procedure 019-361 (Component Connector and Pin Inspection) in Section 19.

If any of the above conditions are found, follow the appropriate procedure below:

  • Repair the damaged pins
  • Repair or replace the engine harness, or replace the sensor, whichever has the damaged pins
  • Flush the dirt, debris, or moisture from the connector pins, use electronic contact cleaner, Part Number 3824510
  • Install the appropriate connector seal if it is damaged or missing.

Repair the engine harness.
Refer to Procedure 019-220 (Augat™ Connector Series) in Section 19.

Replace the engine harness.

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Inspect the sensor.

Disconnect the EPS and ECM connectors.

Inspect the engine position sensor for the following:

  • Metal debris on the end of the sensor
  • Damage to the end of the sensor caused by the engine gear
  • Oil leakage or insulation problems such as swelling
  • Damaged electrical potting in the sensing end of the sensor.

If any of the above conditions are found, follow the appropriate procedure below.

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Resistance Check

 TOC

Disconnect the EPS and ECM connectors.

Use a multimeter to check the resistance of the sensor.

  • Measure the resistance from the engine position sensor SIGNAL pin to the engine position sensor RETURN pin in the engine position sensor connector.
  • Measure the resistance from the engine position backup SIGNAL pin to the engine position backup RETURN pin in the engine position sensor connector.

Refer to the circuit diagram or the wiring diagram for connector pin identification.

For general resistance measurement techniques, refer to Procedure 019-360 (Resistance Measurements Using a Multimeter) in Section 19.

If the resistance is
not between 1000 and 2000 ohms, replace the sensor.

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Check for an open circuit.

Disconnect the EPS and ECM connectors.

  • Use a multimeter to measure the resistance between pin B on the harness side of the EPS connector and pin 4 in the ECM connector.
  • Use a multimeter to measure the resistance between pin C on the harness side of the EPS connector and pin 17 in the ECM connector.

Refer to the circuit diagram or the wiring diagram for connector pin identification.

For general resistance measurement techniques, refer to Procedure 019-360 (Resistance Measurements Using a Multimeter) in Section 19.

If the resistance in either circuit is less than 10 ohms, repair or replace the harness.

Repair the engine harness.
Refer to Procedure 019-202 (Metri-Pack™ Connector Series) in Section 19.

Replace the engine harness.

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Check for Short Circuit to Ground

 TOC

Disconnect the EPS and ECM connectors.

Check for a short circuit to ground.

  • Use a multimeter to measure the resistance from the engine position SIGNAL pin in the engine position sensor connector, sensor side, to the engine block ground.
  • Use a multimeter to measure the resistance from the engine position RETURN pin in the engine position sensor connector, sensor side, to the engine block ground.

Refer to the circuit diagram or the wiring diagram for connector pin identification.

For general resistance measurement techniques, refer to Procedure 019-360 (Resistance Measurements Using a Multimeter) in Section 19.

If the resistance in either circuit is less than 100k ohms, repair or replace the sensor.

Repair the sensor.
Refer to Procedure 019-201 (Weather-Pack™ Connector Series) in Section 19.

Replace the sensor.

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Check for Short Circuit from Pin to Pin

 TOC

Disconnect the EPS and ECM connectors.

Check for a pin-to-pin short circuit.

  • Use a multimeter to measure the resistance between pin 4 and pin 17 to all the other pins in the ECM connector.

Refer to the circuit diagram or the wiring diagram for connector pin identification.

For general resistance measurement techniques, refer to Procedure 019-360 (Resistance Measurements Using a Multimeter) in Section 19.

If the resistance in either circuit is less than 100k ohms, repair or replace the harness.

Repair the engine harness.
Refer to Procedure 019-202 (Metri-Pack™ Connector Series) in Section 19.

Replace the engine harness.

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Check for adequate camshaft speed/position sensor air gap.

Remove the engine position sensor.

Measure the distance between the sensor o-ring sealing surface and the edge of the tone wheel to verify an adequate air gap.

If the air gap distance is less than 33.81 mm [1.33 in] or greater than 34.06 mm [1.34 in], then inspect the camshaft tone wheel/gear teeth for damage or spinning.

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Last Modified:  11-Aug-2008
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