Circuit Description
The DTC P0107 Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage diagnostic monitors the MAP sensor response to pressure changes in the intake manifold. The pressure changes occur based on engine load and the throttle valve opening. The MAP sensor has the following circuits:
| • | A 5-volt reference circuit |
| • | A low reference circuit |
| • | A signal circuit |
The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The PCM receives a low voltage on the signal circuit when manifold vacuum is high at idle or deceleration. The PCM receives a high voltage when manifold vacuum is low at wide open throttle (WOT) or when the ignition is ON and the engine is OFF. The PCM monitors the MAP sensor signal for voltage outside of the normal range and sets a DTC P0107 when the voltage is unusually low.
The following table illustrates the difference between MAP kPa, signal voltage, and engine vacuum.
Engine Condition | MAP kPa | MAP Signal Voltage | Manifold Vacuum |
|---|---|---|---|
Idle | Low | Low | High |
Deceleration | Low | Low | High |
Ignition ON, Engine OFF | High | High | Zero |
Wide-Open Throttle | High | High | Low |
DTC Descriptor
This diagnostic procedure supports the following DTC.
DTC P0107 Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage
Conditions for Running the DTC
| • | The engine is operating. |
| • | DTC P0108 is not set. |
| • | DTC P0107 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
The MAP sensor signal is 0.23 volts or less for at least 2 seconds.
Action Taken When the DTC Sets
| • | The powertrain control module (PCM) illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame/Failure Records. |
| • | The PCM enters the Fail Safe Function and uses default MAP values based on throttle position, while the fuel control system operates in OPEN LOOP. |
Conditions for Clearing the MIL/DTC
| • | The MIL turns OFF after 3 consecutively passing trips without a fault present. |
| • | A history DTC clears after 40 consecutive warm-up cycles without a fault. |
| • | Perform the scan tool Clear DTC Information function. |
Diagnostic Aids
| • | Inspect for a restriction or blockage in the vacuum passage to the MAP sensor orifice. |
| • | An intermittent malfunction may be caused by a fault in the MAP sensor circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittent Conditions . |
| • | If the DTC P0107 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC was first set. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The Diagnostic System Check- Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
-
This step determines if a MAP sensor malfunction is present. The input signal of the MAP sensor should indicate atmospheric pressure with the ignition ON, engine OFF. The MAP sensor will vary with atmospheric pressure. A typical pressure at sea level is 100 kPa (29-30 in Hg).
-
This step checks for an open in the MAP sensor reference voltage circuit.
-
The MAP sensor signal circuit carries a 5 volt bias that can be measured with the DMM. If the measured voltage is near zero there is a short to ground or a faulty PCM.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||
Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | ||
Is the MAP sensor value within the specified range? | 95-100 kPa | Go to Step 3 | Go to Step 4 | |
3 |
Did DTC P0107 set? | -- | Go to Step 4 | Go to Diagnostic Aids |
4 | Was DTC P0502 also set? | -- | Go to Step 9 | Go to Step 5 |
Is the voltage near the specified value? | 5.0 V | Go to Step 6 | Go to Step 8 | |
Measure the voltage of the MAP sensor signal circuit with a DMM. Is the voltage near the specified value? | 4.9 V | Go to Step 10 | Go to Step 7 | |
7 |
Did you find and correct a condition? | -- | Go to Step 12 | Go to Step 11 |
8 | Repair the open in the 5-volt reference sensor circuit between the MAP sensor and SP114. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 12 | -- |
9 | Repair the open in the 5-volt reference sensor circuit between the PCM and SP114. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 12 | -- |
10 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- |
11 |
Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Does the DTC run and pass? | -- | Go to Step 13 | Go to Step 2 |
13 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
