P0101

P0101 00

Mass Air Flow Circuit. Performance Problems.







Fault symptom
Check Engine (OBD II, EOBD).
Cruise control not working.
Limp home
Possible driveability problem.

On-board diagnosis

Type of diagnosis:
Continuous

Enable criteria:
Battery voltage must be between 11 - 16 V.
Vehicle speed over 40 km/h for more than 60 s of accumulated time.
Coolant temperature between 71 degree C and 115 degree C.
Engine speed between 1400 and 4000 rpm.
No fuel shut-off.
Pressure quotient for pressure before and after the valve is between 0.37 and 0.7.
Mass air flow is calculated using the throttle valve angle and the pressure difference before and after the valve.

Fault criteria:
Conditions for test 1, 2, 3 or 4 are fulfilled.

Test 1
- The mass air flow sensor shows a value 12% lower than the calculated one while multiplicative adaptation is greater than 17%.

Test 2
- The mass air flow sensor shows a value 12% higher than the calculated one while multiplicative adaptation is less than -17%.

Test 3
- The mass air flow sensor shows a value 30% lower than the calculated one.

Test 4
- The mass air flow sensor shows a value 30% higher than the calculated one.

Dependent:
P0107, P0108
P0112, P0113
P0237, P0238

System reaction to a fault:
The system is pressure controlled.
Boost pressure adaption is blocked and reset.
Limited acceleration and idle function.
Cruise control blocked.
Secondary air switched off.

OK report:
Diagnosis completed without fault report.

Fault handling:
Type III
(See Description of On-Board Diagnostics/Fault handling III, "Other emission-related components and functions" for more information.)

Checking the wiring harness
Move the wiring harness at several spots and in several directions to reveal intermittent breaks and short-circuits. Check switches, connectors and crimp connections for oxidation, retracted pins and pin clamping force.

Diagnostic help
The DTC indicates that the value from the mass air flow sensor has been deemed unreliable after comparison with a calculated value. This could be due to an air leak or a faulty mass air flow sensor.

First check the integrity of the intake system. Then continue with fault diagnosis.

If DTC P0171 or P0172 is stored, it is cleared by P0101.