P0108 - Manifold Absolute Pressure Sensor Circuit High: Notes

Fig 1: Identifying Manifold Absolute Pressure Sensor Wiring Diagram

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Theory of Operation

The Manifold Absolute Pressure (MAP) sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. The MAP reading gives the Powertrain Control Module (PCM) an indication of the current air pressure within the intake manifold. The PCM uses this information to calculate fuel delivery. The MAP sensor has a 5 Volt reference circuit, a low reference circuit and a signal circuit. The PCM supplies 5 Volts to the MAP sensor on a 5 Volt reference circuit and provides a ground on a low reference circuit. The MAP sensor provides a voltage signal to the PCM on a signal circuit relative to the pressure changes.

>>When Monitored:<< With the ignition on and battery voltage greater than 10.4 volts.
>>Set Condition:<< The Powertrain Control Module (PCM) detects that the Manifold Absolute Pressure (MAP) Sensor input voltage is above the maximum acceptable value.

Possible Causes
(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
(K1) MAP SIGNAL CIRCUIT SHORTED TO VOLTAGE
(K1) MAP SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT
(K1) MAP SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE
(K900) SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE
MAP SENSOR
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to Pre-Diagnostic Troubleshooting Procedure .