Aston Martin diagnostic trouble code
P0103: Mass or Volume Air Flow Circuit High Input
Use this reference to understand the recorded condition, confirm the available V8 Vantage or DB9 manual coverage, and follow the documented diagnostic checks before replacing parts.
- Code family
- Powertrain
- Vehicle system
- Fuel and air
- Manual coverage
- V8 Vantage, DB9
- Warning-lamp status
- V8 Vantage: MIL; DB9: MIL
What Aston Martin code P0103 means
Mass or Volume Air Flow Circuit High Input
DB9 preliminary diagnostic manual · section 2-12
Manufacturer fault-analysis procedure
Manual fault definition
P0103 - The MAF signal went above 4.80 volts
during normal engine running.
during normal engine running.
Cautions and notes
CAUTION: This code may be generated in the
Primary or Secondary PCM. Check that you are
working on the correct half of the engine.
Primary or Secondary PCM. Check that you are
working on the correct half of the engine.
Test sequence and decision path
1. Connect the WDS or Scan Tool. Check that fault
code P0103 is present. Set the datalogger to monitor both MAF signals.
2. P0103 can be caused by a contaminated sensor.
Remove the sensor and check for contamination
on the sensor screen. If contamination is present,
replace the MAF sensor and overhaul the air
intake filter system to repair the contamination
source. Retest after reassembly. If P0103 is still
present, carry out the following analysis.
3. Run the engine up to 1500 rpm for 5 seconds.
Read the MAF signal levels and check which
MAF voltage is above 4.80V.
4. Key off, disconnect the suspect MAF sensor, key
on. Check the MAF signal again.
If the voltage is still above 4.60V, there is a short
between +12V Power and the MAF signal line to
Primary PCM pin C0634-9 or Secondary PCM pin
C0637-9. Repair the short circuit and go to step
5. If the voltage has dropped to below 0.24 volts,
there is an internal short from Vpower to the MAF
signal line inside the sensor. Replace the MAF
sensor.
5. Clear the P0103 code. Run the KOER test and
check that P0103 does not recur.
Open the corresponding manual page for wiring diagrams and figures
code P0103 is present. Set the datalogger to monitor both MAF signals.
2. P0103 can be caused by a contaminated sensor.
Remove the sensor and check for contamination
on the sensor screen. If contamination is present,
replace the MAF sensor and overhaul the air
intake filter system to repair the contamination
source. Retest after reassembly. If P0103 is still
present, carry out the following analysis.
3. Run the engine up to 1500 rpm for 5 seconds.
Read the MAF signal levels and check which
MAF voltage is above 4.80V.
4. Key off, disconnect the suspect MAF sensor, key
on. Check the MAF signal again.
If the voltage is still above 4.60V, there is a short
between +12V Power and the MAF signal line to
Primary PCM pin C0634-9 or Secondary PCM pin
C0637-9. Repair the short circuit and go to step
5. If the voltage has dropped to below 0.24 volts,
there is an internal short from Vpower to the MAF
signal line inside the sensor. Replace the MAF
sensor.
5. Clear the P0103 code. Run the KOER test and
check that P0103 does not recur.