Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Code P1107, Map Intermittent Low - "S" & "T" Series 4.3L (VIN W): Notes
Manifold Absolute Pressure (MAP) sensor responds to changes in manifold pressure (vacuum). Control module receives this information as a signal voltage that varies from 1-1.5 volts at idle to 4-4.6 volts at full throttle. Scan tool displays manifold pressure in volts. Low pressure (high vacuum) reads a low voltage, while high pressure (low vacuum) reads a high voltage. If MAP sensor fails, control module will substitute a fixed MAP value and use throttle position sensor to control fuel delivery.
- Determines if code is set because of a hard failure or intermittent condition.
- Jumping circuits determines if sensor is at fault or if problem exists in control module or wiring.
- Tech 1 may not display 5 volts. What is important is that control module recognized voltage as more than 4 volts, indicating that control module and circuit are okay.
- Determines if 5 volts are present at sensor.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.