Circuit/System Testing

WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

Verify the condition does not exist:
- Restricted exhaust system.
- A leak in the intake system.
- Inspect the hoses and pipes for a leakage or restriction.
- Clogged exhaust gas recirculation valve.
- Loose clamps, cracks, or other damages to the intake system.
- Restrictions in the intake system.
- Clogged air cleaner.
- Vacuum hoses with kinks, leaks, or improper connections.
- Water intrusion at the mass air flow sensor.
- Contamination of the measuring element of the mass air flow sensor.
- If a condition exists
  Repair or replace as necessary.
- Go to next step: If no condition exists

NOTE:

It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

Ignition/Vehicle & All vehicle systems - Off
Disconnect the electrical connector: B75C Multifunction Intake Air Sensor
Test for less than 5 ohms between the test points:Ground circuit terminal 7 & Ground
- If 5 ohms or greater
1. Disconnect the appropriate ground connection:
2. Test for less than 2 ohms between the test points: Ground circuit terminal 7 @ Component harness & Ground
  - If 2 ohms or greater - Repair the open/high resistance in the circuit.
  - If less than 2 ohms - Repair the open/high resistance in the ground connection.
- Go to next step: If less than 5 ohms
Ignition - On / Vehicle - In Service Mode
Connect a test lamp between the test points: Ignition circuit terminal 5 & Ground
Verify the test lamp turns On.
- If the test lamp does not turn On and the circuit fuse is OK
1. Ignition/Vehicle - Off & Remove - Test lamp
2. Disconnect the electrical connector:X3 @ K20 Engine Control Module
3. Test for infinite resistance between the test points: Ignition circuit terminal 5 @ Component harness & Ground
  - If less than infinite resistance - Repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
4. Test for less than 2 ohms between the test points: Ignition circuit terminal 5 @ Component harness & Terminal 53 @ K20 Engine Control Module
  - If 2 ohms or greater - Repair the open/high resistance in the circuit.
  - If less than 2 ohms - Replace the component: K20 Engine Control Module
- Go to next step: If the test lamp turns On
Ignition - On / Vehicle - In Service Mode
Test for 4.8 to 5.2 V between the test points:Signal circuit terminal 6 & Ground
- If less than 4.8 V
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: X1 @ K20 Engine Control Module
3. Test for infinite resistance between the test points:Signal circuit terminal 6 @ B75C Multifunction Intake Air Sensor & Ground
  - If less than infinite resistance - Repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
4. Test for less than 2 ohms between the test points:Signal circuit terminal 6 @ B75C Multifunction Intake Air Sensor & Circuit terminal 34 X1 @ K20 Engine Control Module
  - If 2 ohms or greater - Repair the open/high resistance in the circuit.
  - If less than 2 ohms - Replace the component: K20 Engine Control Module
- If greater than 5.2 V
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: X1 @ K20 Engine Control Module
3. Ignition - On / Vehicle - In Service Mode
4. Test for less than 1 V between the test points: Signal circuit terminal 6 @ B75C Multifunction Intake Air Sensor & Ground
  - If 1 V or greater - Repair the short to voltage on the circuit.
  - If less than 1 V - Replace the component: K20 Engine Control Module
- Go to next step: If between 4.8 and 5.2 V
Test or replace the component:B75C Multifunction Intake Air Sensor