Circuit Descriptions
The manifold absolute pressure (MAP) sensor is a variable resistor that responds to changes in manifold pressure, vacuum. The PCM measures the voltage drop across the MAP sensor. The voltage ranges from 1-1.5 volts at idle, high vacuum, to 4-4.5 volts at wide open throttle, low vacuum.
Conditions for Setting the DTC
Important: The MAP signal is continuously checked when the engine is running.
DTC P0108 will set if the MAP is greater than 4.9 volts (90 kPa) when either:
- The engine speed is greater than 1,600 RPM.
- The TP sensor is less than 70 percent.
- No TP sensor DTCs have been set.
OR
- The engine speed is less than 1,600 RPM.
- The TP sensor is less than 50 percent.
- No TP sensor DTCs have been set.
Diagnostic Aids
With the engine OFF and key ON, the MAP reading should be the same as the barometric reading because manifold pressure is equal to atmospheric pressure, no vacuum -- high voltage. Comparing this reading to a known good vehicle with the same sensor is a good way to check accuracy of a suspect sensor. Readings should be within 0.4 volts.
LOW ALTITUDE = HIGH PRESSURE = HIGH VOLTAGE
Altitude | Voltage Range | kPa |
|---|---|---|
BELOW 305 m (BELOW 1,000 ft) | 3.8-5.5 V | 98-100 kPa |
305-610 m (1,000-2,000 ft) | 3.6-5.3 V | 98-95 kPa |
610-914 m (2,000-3,000 ft) | 3.5-5.1 V | 95-92 kPa |
914-1219 m (3,000-4,000 ft) | 3.3-5 V | 92-89 kPa |
1219-1524 m (4,000-5,000 ft) | 3.2-4.8 V | 89-86 kPa |
1524-1829 m (5,000-6,000 ft) | 3-4.6 V | 86-83 kPa |
1829-2133 m (6,000-7,000 ft) | 2.9-4.5 V | 83-80 kPa |
2133-2438 m (7,000-8,000 ft) | 2.8-4.3 V | 80-77 kPa |
2438-2743 m (8,000-9,000 ft) | 2.6-4.2 V | 77-74 kPa |
2743-3948 m (9,000-10,000 ft) | 2.5-4 V | 74-71 kPa |
