OBD-II Code · Sensors
P0108
MAP Sensor Circuit High Input
Severity
medium
Worth booking. It costs fuel, emissions or comfort until it is fixed.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$80–$250
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
MAP sensor reading too high.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
- Hesitation
- Poor fuel economy
Likely causes
- Failed MAP sensorMost common
- Wiring short to power
- Disconnected vacuum reference
Read the full diagnostic procedureP0108 means MAP signal voltage is above the ceiling — over 4.9V on a 1-bar sensor with the engine running at idle, or over 4.9V on a 3-bar sensor at…
P0108 means MAP signal voltage is above the ceiling — over 4.9V on a 1-bar sensor with the engine running at idle, or over 4.9V on a 3-bar sensor at non-boost conditions. The sensor is reporting maximum pressure when the actual manifold pressure should be vacuum at idle.
Cheapest-first ladder
- check the vacuum reference first — a disconnected or clogged vacuum hose between the manifold and the MAP sensor will set P0108 instantly because the sensor reads atmospheric (which on a 1-bar sensor IS the ceiling) instead of idle vacuum; pull the MAP and inspect the port for carbon blockage on direct-injection engines (very common on VW/Audi 2.0T, BMW N54, Ford EcoBoost — the manifold port chokes with carbon and the sensor reads ambient cabin air pressure); back-probe the signal wire engine running at warm idle, must be 1.0-1.5V on a 1-bar at idle vacuum of 30-40 kPa — if signal voltage is 4.7V at idle the sensor is seeing atmospheric, which is mechanical not electrical; verify the 5V reference is not shorted to the signal wire by ohming the sensor with the connector unplugged; verify ground integrity.
- A P0108 on a turbo engine at idle is mechanical 95% of the time — clogged port or disconnected hose — and replacing the sensor will not fix it.
Vehicle-specific patterns2008-2014 VW/Audi 2.0T TSI (CCTA, CBFA, CAEB) sets P0108 from carbon plugging the MAP sensor port in the intake manifold, requiring walnut-blast inta…
- 2008-2014VW/Audi 2.0T TSI (CCTA, CBFA, CAEB) sets P0108 from carbon plugging the MAP sensor port in the intake manifold, requiring walnut-blast intake cleaning before the sensor can read correctly;
- 2007-2013GM 5.3L Silverado/Tahoe sees P0108 when the MAP sensor port under the intake manifold valley cover gets blocked by oil residue from AFM-related blow-by;
- 2007-2018Cummins 5.9L/6.7L Ram sees P0108 from soot completely plugging the intake horn MAP port to where atmospheric air cannot reach the silicon element;
- 2010-2016BMW N20/N55 sets P0108 from carbon buildup on intake valves restricting actual MAP reading combined with sensor port partial blockage.
Estimated repair$40 to $600.
Look up another code
P0108 — frequently asked
What does a P0108 code mean?
MAP sensor reading too high.
What causes a P0108 code?
Common causes: Failed MAP sensor; Wiring short to power; Disconnected vacuum reference.
What are the symptoms of a P0108 code?
Typical symptoms: Check engine light; Hesitation; Poor fuel economy.
Is it safe to drive with a P0108 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $80-$250.
How do I diagnose a P0108 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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