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.
- Verify none of the following conditions exist:
- A loose or disconnected charge air cooler hose or pipe; where equipped
- A blocked or obstructed charge air cooler, including: after-market grill covers; where equipped
- Any snow or ice build-up at the charge air cooler in cold climates; where equipped
- Any mud or dirt build-up at the charge air cooler; where equipped
- A restricted or collapsed air intake duct
- An intake manifold leak
- A MAP sensor seal that is leaking, missing, or damaged
- A restricted or collapsed air intake duct
- A misaligned or damaged air intake duct
- Any water intrusion in the induction system
- An Intake Manifold Resonator with a leaking seal, or a cracked or broken housing
- If a condition exists
Repair or replace component as appropriate.
- If no condition exists
- Ignition OFF and all systems OFF, it may take up to for 2 minutes for all vehicle systems to power down. Disconnect the harness connector at the B75B Mass Air Flow /Intake Air Temperature sensor.
- Test for less than 2 Ω between the low reference circuit terminal D and ground.
- If 2 Ω or greater
- Ignition OFF, disconnect the harness connector at the engine control module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open or high resistance in the circuit.
- If less than 2 Ω replace the engine control module.
- If less than 2 Ω
- Ignition ON, test for 4.8-5.2 V between the intake air temperature signal 1 circuit terminal E and ground.
- If less than 4.8 V
- Ignition OFF, disconnect the harness connector at the engine control module.
- 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
- 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 engine control module.
- If greater than 5.2 V
- Ignition OFF, disconnect the harness connector at the engine control module.
- 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 engine control module.
NOTE:If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.
- If between 4.8-5.2 V
- Ignition ON, verify the scan tool IAT Sensor 1 parameter is colder than -39°C (-38°F).
- If not colder than -39°C (-38°F).
Replace the engine control module.
- If colder than -39°C (-38°F).
- If not colder than -39°C (-38°F).
- Ignition OFF. Install a 3 A fused jumper wire between the signal circuit terminal E and low reference circuit terminal D.
- Ignition ON. Verify the scan tool IAT Sensor 1 parameter is warmer than 149°C (300°F).
- If not warmer than 149°C (300°F).
Replace the K20 Engine Control Module.
- If warmer than 149°C (300°F).
- If not warmer than 149°C (300°F).
- Test or replace the B75B Mass Air Flow /Intake Air Temperature sensor.