Applicable Systems
OBD-II
Symptoms
Check engine light is on. The engine may run lean, hesitate under load, or have reduced power. The MAP sensor signal exceeds the maximum expected value.
Possible Causes
- MAP sensor signal circuit shorted to 5V reference
- Faulty MAP sensor producing high output
- Vacuum line to MAP sensor is blocked or restricted
- Aftermarket MAP sensor with incorrect calibration
- ECM reference voltage too high
Troubleshooting Steps
- 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
How to Reset
To reset code P0108: 1) Repair the underlying fault. 2) Use an OBD-II scan tool to clear the DTC. 3) Perform a drive cycle to verify the monitor completes. 4) If the code returns, further diagnosis is needed. Caution: Do not clear codes without fixing the root cause.
Frequently Asked Questions
- Q: What does OBD-II code P0108 mean?
Code P0108 indicates: Manifold Absolute Pressure Circuit High Input. This is a SAE J2012 standard diagnostic trouble code related to Fuel and Air Metering.
- Q: Is code P0108 serious?
Severity: Major. Immediate attention is recommended to prevent further damage.
- Q: Can I drive with code P0108?
It is not recommended to drive with this code active as it may cause further damage or safety issues.
- Q: How do I fix code P0108?
Diagnose the Fuel and Air Metering system, check wiring and connectors, test the related sensor or actuator, and replace faulty components as needed.
Source: SAE J2012 Standard - Powertrain Diagnostic Trouble Codes
Category: OBD-II