OBD-II Error Code P1603 - Mass Air Flow Sensor Signal Intermittent

OBD-II Standard OBD-II Minor Fuel and Air

Model: SAE J2012 Extended | Code: P1603

Applicable Systems

OBD-II

Symptoms

The mass air flow sensor signal is intermittently outside the expected range.

Step 1: Connect an OBD-II scan tool and read all stored DTCs and freeze frame data
All DTCs and freeze frame data are retrieved
Step 2: Inspect the related sensor or actuator wiring for damage, corrosion, or loose connections
Wiring and connectors are in good condition
Step 3: Use a digital multimeter to check sensor voltage, resistance, and reference signals per manufacturer specifications
Values are within specified range
Step 4: Perform component-level testing of the suspected sensor or actuator
Component passes or fails definitively
Step 5: Clear codes and road test to verify repair
Code does not return and system operates normally

To reset code P1603: 1) Repair the underlying fault. 2) Use an OBD-II scan tool to clear the DTC. 3) Perform a drive cycle.

Q: What does OBD-II code P1603 mean?
Code P1603 indicates: Mass Air Flow Sensor Signal Intermittent. This is a Mercedes-Benz manufacturer-specific diagnostic trouble code.
Q: Is code P1603 serious?
Severity: Minor. Service as needed.
Q: How do I fix code P1603?
Diagnose the Fuel and Air system and replace faulty components.