ISB/ISBe Series Engines – 019-127   Water in Fuel Sensor

The water separator and water-in-fuel sensor is installed by the vehicle’s OEM. It is

not located on the engine. The water-in-fuel sensor sends a signal to the electronic control module (ECM) when a set volume of water has accumulated in the fuel filter. The water-in-fuel circuit contains two wires, a return ground (pin 32) and a signal wire (pin 87).

NOTE: The water-in-fuel sensor is the signal wire (pin 87) and the return wire (pin 32) in the OEM harness connector.

Disconnect the OEM harness from the ECM.

Check for damaged pins.

Disconnect the water-in-fuel sensor from the OEM harness.

Return Wire Resistance – Checking

CAUTION  To reduce the possibility of damage to the connector pins, do not use probes or leads other than Part Number 3164112. The leads must fit tightly in the connector without expanding the pins of the connector.

Insert the test lead into pin 32 of the OEM harness connector. Connect the alligator clip to the multimeter probe. Touch the other multimeter probe to pin A of the water-in-fuel sensor, harness side.

Measure the resistance.

The multimeter

must show a closed circuit (10 ohms or less).

If more than 10 ohms are measured, there is an open circuit in the return supply wire. Repair the wire, or replace the OEM harness. Refer to Procedure

019-323 or

019-071.

Signal Wire Resistance – Checking

Insert the test lead into pin 87 of the engine harness connector. Connect the alligator clip to the multimeter probe. Touch the other multimeter probe to pin B of the water-in-fuel sensor, harness side.

Measure the resistance.

The multimeter

must show a closed circuit (10 ohms or less).

If more than 10 ohms are measured, there is an open circuit in the signal supply wire. Repair the wire, or replace the OEM harness. Refer to Procedure

019-323 or

019-071.