P0108 on a GMC: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

Safe to drive, but the engine may idle rough, hesitate, and use more fuel until the sensor is fixed.

What P0108 means on a GMC

On a GMC, P0108 means the manifold absolute pressure (MAP) sensor voltage is too high. GM engines in GMC trucks and SUVs use MAP sensors to track engine load, and a failed sensor or shorted wire will trigger this code and can hurt driveability.

Is P0108 common on GMCs?

Sierra, Yukon, Terrain, and Acadia models see P0108 as they age, usually from the sensor failing or the harness chafing near the intake. GM MAP sensors are inexpensive, so this is often a quick, low-cost fix.

Commonly reported on: Sierra, Yukon, Terrain, Acadia.

Symptoms

Check engine light on
Rough idle
Hesitation when accelerating
Worse fuel economy

Common causes

most common: Faulty MAP sensor
common: Signal wire shorted toward 5 volts
common: Chafed wiring harness near the sensor
less common: Corroded or loose connector terminals

How to fix it

Fix	DIY?	Typical cost
Replace the MAP sensor	Yes	$25–70
Repair the wiring or connector	Mechanic	$50–150
Have a shop replace the sensor and verify the circuit	Mechanic	$100–200