Circuit/System Testing
- Inspect for the following conditions:
- Vacuum hoses for splits, kinks, and proper connections
- Inspect thoroughly for any type of leak or restriction.
- Air leaks at throttle body mounting area and intake manifold sealing surfaces
- Ignition OFF for 90 seconds, determine the current vehicle testing altitude. Ignition ON, engine OFF, observe the scan tool BARO parameter. Compare the parameter to the Altitude Versus Barometric Pressure
table. The BARO parameter should be within the specified range as indicated in the table.
- Take a snapshot of the engine data list while performing the actions listed below. The MAF sensor kg/h should increase as the engine speed is increased and decrease as the throttle is returned to idle.
- Idle the engine.
- Increase the engine speed slowly to 3, 000 RPM, then back to idle.
- Exit from the snapshot and review the data.
- Observe the MAF Sensor parameter frame by frame with a scan tool. The MAF sensor g/s should change smoothly and gradually as the engine speed is increased and is returned to idle.
- If the MAF sensor g/s does not change smoothly and gradually as the engine speed is increased and is returned to idle refer to DTC P0101 or P1101 .
- Inspect the throttle body for the following conditions:
- Loose or damaged throttle blade
- Broken throttle shaft
- Any throttle body damage
- If any of these conditions exist, replace the throttle body assembly.