Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

NOTE:

You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

Ignition OFF, disconnect the harness connector at the B75C Multifunction Intake Air sensor.
Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 2 Ω between the ground circuit terminal 7 and ground.
- If 2 Ω or greater
1. Ignition OFF. Disconnect the sensor chassis ground.
2. Test for less than 2 Ω in the ground circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, repair the open/high resistance in the chassis ground connection.
- Go to next step: If less than 2 Ω
Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 5 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF, remove the test lamp and remove the fuse for the ignition voltage circuit.
2. Test for less than 2 Ω in the ignition voltage circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF, remove the test lamp and remove the fuse for the ignition voltage circuit.
2. Test for infinite resistance between the ignition voltage circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance, test all components connected to the ignition circuit, replace as necessary.
- If 2 Ω or greater, repair the open or high resistance in the circuit.
- If the circuit tests normal and the fuse is open, test all the components connected to the circuit and repair or replace as necessary.
- Go to next step: If a test lamp illuminates
Ignition ON, test for 4.8 - 5.2 volts between the signal circuit terminal 6 and ground.
- If less than 4.8 V
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K20 Engine Control Module.
- If greater than 5.2 V
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Ignition ON, test for less than 1 V between the signal circuit and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V, replace the K20 Engine Control Module.
- Go to next step: If between 4.8 - 5.2 V
Ignition OFF, connect the leads of the EL-38522 Variable Signal Generator as follows:
- Red lead to the signal circuit terminal 6 at the harness connector
- Black leads to ground
- Battery voltage supply lead to B+
Set the EL-38522 Variable Signal Generator to the following specifications.
- Signal switch to 5 V
- Frequency switch to 5 kHz
- Duty Cycle switch to 50% (Normal)
Engine idling, verify the scan tool MAF Sensor parameter is between 4950 - 5050 Hz.
- If not between 4950 - 5050 Hz.
  If not between 4950 - 5050 Hz, replace the K20 Engine Control Module.
- Go to next step: If between 4950 - 5050 Hz.
Test or replace the B75C Multifunction Intake Air sensor.