• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
5-Volt Reference | P0405, P0642 | P0107 | P0404, P0405, P0605, P0643 | -- |
MAP Sensor Signal | P0107 | P0107 | P0108, P0404, P0605, P0643 | -- |
Low Reference | -- | P0108 | -- | -- |
Important: The scan tool MAP sensor pressure parameter freezes when a DTC sets. The pressure parameter remains fixed until the DTC is cleared and the fault no longer exists.
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: 1.1-1.2 V | |||
5-Volt Reference | 0 Volts | 0 Volts | 5 Volts |
MAP Sensor Signal | 0 Volts | 0 Volts | 5 Volts |
Low Reference | -- | 4.2-4.6 Volts | * |
* Internal ECM damage may occur if the circuit is shorted to B+. |
The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The engine control module (ECM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The ECM provides a ground on the low reference circuit. The MAP sensor provides a signal to the ECM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The ECM detects a low signal voltage at a low MAP, such as during an idle or a deceleration. The ECM detects a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at or near WOT.
• | The ignition is ON. |
• | The DTCs run continuously once the above conditions are met. |
The ECM detects that the MAP sensor is less than 0.3 volt.
The ECM detects that the MAP sensor is greater than 4.9 volts.
DTC P0107 and P0108 are Type A DTCs.
DTC P0107 and P0108 are Type A DTCs.
If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 23738-A Vacuum Pump
⇒ | If any DTCs are set, refer to DTC P0652 or P0653. |
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
Important: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.
⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
• | Disconnect the vacuum supply hose from the MAP sensor. |
• | Remove the MAP sensor from the intake manifold. |
⇒ | If not within the specified range, replace the MAP sensor. |
⇒ | If not with in the specified range, replace the MAP sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for engine control module replacement, setup, and programming |