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 2Ω between the ground circuit terminal 7 and ground.
- If 2Ω or greater
1. Ignition OFF. Disconnect the sensor chassis ground.
2. Test for less than 2Ω in the ground circuit end to end.
  - If 2Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2Ω, repair the open/high resistance in the chassis ground connection.
- If less than 2Ω
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 2Ω in the ignition voltage circuit end to end.
  - If 2Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2Ω, 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 a test lamp illuminates
Ignition ON, test for 4.8-5.2V between the signal circuit terminal 6 and ground.
- If less than 4.8V
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.
  - If infinite resistance
3. Test for less than 2Ω in the signal circuit end to end.
  - If 2Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2Ω, replace the K20 Engine Control Module.
- If greater than 5.2V
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Ignition ON, test for less than 1V between the signal circuit and ground.
  - If 1V or greater, repair the short to voltage on the circuit.
  - If less than 1V, replace the K20 Engine Control Module.
- If between 4.8-5.2V
Determine if EL-38522-A Variable Signal Generator or equivalent is available.
- EL-38522-A, Variable Signal Generator; or equivalent is not available
1. Test or replace the B75C Multifunction Intake Air sensor
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
3. Verify the DTC does not set.
  - If the DTC sets
    Replace the K20 Engine Control Module.
  - If no DTCs set
4. All OK.
- EL-38522-A, Variable Signal Generator; or equivalent is available
Ignition OFF, connect the leads of the EL-38522-A Variable Signal Generator as follows:
- Red lead to the signal circuit terminal 3 at the harness connector
- Black leads to ground
- Battery voltage supply lead to B+
Set the EL-38522-A Variable Signal Generator to the following specifications.
- Signal switch to 5V
- Frequency switch to 5kHz
- Duty Cycle switch to 50% (Normal)
Engine idling, verify the scan tool MAF Sensor parameter is between 4,950-5,050 Hz.
- If not between 4,950-5,050 Hz.
  Replace the K20 Engine Control Module.
- If between 4,950-5,050 Hz.
Test or replace the B75C Multifunction Intake Air sensor.