## Diesel Engine Management System

#### DTC Troubleshooting

11-47

DTC P0101: MAF System Performance

1. Check the ''On Board Diagnostic (OBD) System Check''.

Was the ''OBD System Check'' performed?

YES – Go to step 2.

NO – Go to OBD System Check.

1. Check the DTC.

Are there any other (beside DTC P0101) being output?

YES – Go to relevant DTC chart.

NO – Go to step 3.

1. Check the MAF with the scan tool.

Is about 8 – 13 g/sec indicated at idling?

YES – Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the MAF sensor and at the ECM.

NO – Go to step 4.

1. Check for the following conditions:

- Damaged MAF sensor

- MAF/IAT sensor 5P connector (A)
- Air Cleaner (B)
- MAF/IAT sensor (C)
- Duct (D)

- The duct work at the MAF sensor for leaks
- PCV system vacuum leaks
- Incorrect PCV valve
- Vacuum leaks in EGR valve flange and pipes
- Intake manifold vacuum leaks

Is a problem found?

YES – Repair as necessary.

NO – Go to step 5.

1. Start the engine and allow it to idle.

1. Turn the ignition switch OFF.

1. Disconnect the MAF sensor 5P connector.

1. Disconnect ECM connector.

1. Check the MAF sensor signal and +5 V circuits for an open or short to ground.

Wire side of female terminals

MAF/IAT sensor 5P connector

JUMPER WIRE

Is a problem found?

YES – Repair the MAF signal or +5 V circuit.

NO – Go to step 10.

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