Electronic Control System Gas Plus Engines – 019-350   Gas Mass Flow Sensor Circuit

Disconnect engine harness Electronic Control Module (ECM) connector 1 from the ECM. Disconnect the voltage converter from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the gas mass flow sensor signal pin in the engine harness ECM connector 1 to the corresponding pin in the engine harness voltage converter connector.

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

If the circuit is not closed, there is an open circuit in the sensor signal wire.

Repair or replace the engine harness. Refer to Procedure 019-204, 019-220, or 019-043.

Measure the resistance from the voltage converter return pin in the engine harness to the block ground.

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

If the circuits are not closed, there is an open circuit in the voltage converter return wires. Repair or replace the engine harness. Refer to Procedure 019-204, 019-220, or 019-043.

Disconnect the engine harness 31 pin connector from the OEM harness.

Disconnect the voltage converter from the engine harness.

Measure the resistance from the voltage converter +12 VDC supply pin in the 31 pin connector to the corresponding pin in the engine harness voltage converter connector.

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

If the circuit is not closed, there is an open circuit in the voltage converter supply +12 VDC wire. Repair or replace the engine harness. Refer to Procedure 019-204, 019-220, or 019-043.

Disconnect the engine harness from the voltage converter.

Disconnect the voltage converter from the gas mass flow sensor. Set the multimeter to measure resistance.

Measure the resistance from the gas mass flow sensor signal pin on the sensor connector to the signal pin on the voltage converter.

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

If the circuit is not closed, there is an open circuit in the gas mass flow signal wire.

Repair or replace the voltage converter. Refer to Procedure 019-218, or 019-439.

Measure the resistance from the gas mass flow sensor return pins on the sensor connector to the return pins on the voltage converter.

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

If the circuit is not closed, there is an open circuit in the gas mass flow return wire.

Repair or replace the voltage converter. Refer to Procedure 019-218, or 019-439.

Disconnect engine harness Electronic Control Module (ECM) connector 1 from the ECM. Disconnect the gas mass flow sensor from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the gas mass flow sensor supply voltage +12 VDC pin in the engine harness ECM connector 1 to the corresponding pin in the engine harness sensor connector.

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

If the circuit is not closed, there is an open circuit in the sensor supply voltage +12 VDC wire.

Repair or replace the engine harness. Refer to Procedure 019-204, 019-220, or 019-043.

Measure the resistance from the gas mass flow sensor return pin in the engine harness ECM connector 1 to the corresponding pins in the engine harness sensor connector.

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

If the circuits are not closed, there is an open circuit in either gas mass flow sensor return wire. Repair or replace the engine harness. Refer to Procedure 019-204, 019-220, or 019-043.

Disconnect engine harness 31 pin connector from the OEM harness. Disconnect the sensor supply voltage converter connector from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the sensor supply voltage converter supply voltage +12 VDC pin in the engine harness 31 pin connector to engine block ground.

The multimeter must show an open circuit (100k ohms or more).

If the circuit is not open, there is a short circuit to ground in the sensor supply voltage converter +12 VDC wire.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Disconnect the engine harness ECM connector 1 from the ECM.

Measure the resistance from the gas mass flow sensor signal pin in the engine harness ECM connector 1 to engine block ground.

The multimeter must show an open circuit (100k ohms or more).

If the circuit is not open, there is a short circuit to ground in the gas mass flow sensor signal wire.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Disconnect engine harness ECM connector 1 from the ECM. Disconnect the gas mass flow sensor from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the gas mass flow sensor supply voltage +12 VDC pin in the engine harness ECM connector to engine block ground.

The multimeter must show an open circuit (100k ohms or more).

If the circuit is not open, there is a short circuit to ground in the sensor supply voltage +12 VDC wire.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Measure the resistance from the gas mass flow sensor return pin in the engine harness ECM connector 1 to engine block ground.

The multimeter must show an open circuit (100k ohms or more).

If the circuit is not open, there is a short circuit to ground in the gas mass flow sensor return wire. Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Disconnect engine harness ECM connectors 1 and 2 from the ECM. Disconnect the sensor supply voltage converter connector from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the gas mass flow sensor signal pin in the engine harness ECM connector 1 to all other pins in engine harness ECM connector 1.

The multimeter must show an open circuit at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Measure the resistance from the gas mass flow sensor signal pin in engine harness ECM connector 1 to all pins in engine harness ECM connector 2.

The multimeter must show an open circuit (100k ohms or more) at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Disconnect the engine harness 31 pin connector from the OEM harness.

Disconnect the voltage converter from the engine.

Disconnect the engine harness ECM connectors 1 and 2.

Set the multimeter to measure resistance.

Measure the resistance from the voltage converter +12 VDC supply pin in the 31 pin connector to all other pins in the 31 pin connector.

The multimeter must show an open circuit (100k ohms or more) at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Disconnect the engine harness 31 pin connector from the OEM harness.

Disconnect the voltage converter from the engine.

Disconnect the engine harness ECM connectors 1 and 2.

Set the multimeter to measure resistance.

Measure the resistance from the voltage converter +12 VDC supply pin in the 31 pin connector to all other pins in the engine harness ECM connectors 1 and 2.

The multimeter must show an open circuit (100k ohms or more) at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Disconnect the engine harness from the voltage converter.

Disconnect the voltage converter from the gas mass flow sensor. Set the multimeter to measure resistance.

Measure the resistance from the gas mass flow sensor signal pin on the sensor connector to the signal pin on the sensor converter.

The multimeter must show a open circuit (100k ohms or more) at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the voltage converter. Refer to Procedure 019-218, or 019-439.

Measure the resistance from the gas mass flow sensor +12 VDC supply pin on the sensor connector to all other pins on the sensor connector.

The multimeter must show a open circuit (100k ohms or more) at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the voltage converter. Refer to Procedure 019-218, or 019-439.

Disconnect engine harness ECM connectors 1 and 2 from the ECM. Disconnect the gas mass flow sensor from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the gas mass flow sensor supply voltage +12 VDC pin in the engine harness ECM connector 1 to all other pins in engine harness ECM connector 1.

Repeat the check from the gas mass flow sensor return pin in the engine harness ECM connector 1 to all other pins in the connector.

The multimeter must show an open circuit at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.

Measure the resistance from the gas mass flow sensor supply voltage +12 VDC pin in engine harness ECM connector 1 to all pins in engine harness ECM connector 2.

Repeat the check from the gas mass flow sensor return pin in engine harness ECM connector 1 to all pins in engine harness ECM connector 2.

The multimeter must show an open circuit (100k ohms or more) at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the engine harness. Refer to Procedure 019-204 or 019-043.