Specifications

TEST ACTION APPLICABILITY
2 Start and idle the engine.
With the DRBIIIt in Sensors, read the MAF mg/strk and compare it to the MAF
SPEC mg/strk with the engine at idle.
NOTE: The MAF Sensor reading should be within 5% of the MAF Spec
reading.
Is the MAF Sensor reading within 5% of the MAF Spec?
All
Yes → Go To 3
No → Go To 7
3 Place the transmission in Park or Neutral for this test.
Start the engine and increase engine the engine speed to 3000 RPM.
With the DRBIIIt in Sensors, read the MAF mg/strk and compare it to the MAF
SPEC mg/strk with the engine speed at 3000 RPM.
NOTE: The MAF Sensor reading should be within 5% of the MAF Spec
reading.
Is the MAF Sensor reading within 5% of the MAF Spec?
All
Yes → Go To 4
No → Go To 7
4 NOTE: Inspect the complete exhaust system for restriction. Restrictions in
the exhaust system can cause improper EGR flow. Repair as necessary
Allow the engine to idle until the engine reaches operating temperature.
With the DRBIIIt, actuate the EGR Positioner with the engine idling.
NOTE: The EGR Positioner will actuate from 5% to 95%. With the engine
idling at approximately 680 RPM the MAF reading should switch a mini-
mum of 200 mg/strk between 5% and 95% of EGR actuation.
Note the MAF readings.
Does the MAF switch a minimum of 200 mg/strk between 5% and 95% of EGR
actuation?
All
Yes → Go To 5
No → Go To 6
5 Allow the engine to idle until the engine reaches operating temperature.
With the DRBIIIt, actuate the EGR Positioner with the engine speed at 1200 RPM.
NOTE: The EGR Positioner will actuate from 5% to 95%. With the engine
speed at approximately 1200 RPM the MAF reading should switch a mini-
mum of 200 mg/strk between 5% and 95% of EGR actuation.
Note the MAF readings.
Does the MAF switch a minimum of 200 mg/strk between 5% and 95% of EGR
actuation?
All
Yes → No problem found. Test complete.
Perform ROAD TEST VERIFICATION - VER-2.
No → Go To 6
6 Turn the ignition off.
Remove the EGR valve and check the valve and flow passages for debris or other
restrictions.
Were any problems found?
All
Yes → Clean or repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No → Replace the EGR Valve.
Perform ROAD TEST VERIFICATION - VER-2.
151
DRIVEABILITY - DIESEL
P2066-MASS AIR FLOW SENSOR PLAUSIBILITY — Continued