Circuit Description
The Manifold Absolute Pressure (MAP) sensor responds to changes in the intake manifold pressure (vacuum). A 5 volt reference is applied to the sensor on the 5 volt reference circuit. A variable resistor moves in relation to the manifold pressure and a voltage signal is sent back to the VCM on the MAP signal circuit. This voltage signal varies from 1.0-1.5 volts at closed throttle to 4.0-4.5 volts at wide open throttle (low vacuum). The VCM utilizes the MAP signal and throttle position in order to determine the correct amount of fuel delivered to the engine. This DTC is a type A DTC.
Conditions for Setting the DTC
| • | No TP sensor DTCs |
| • | Engine operating |
| • | Throttle Position is at least 0% when engine speed is no more than 800 RPM |
| • | Throttle Position is at least 12.5% when engine speed is greater than 800 RPM |
| • | MAP voltage less than 0.05 volts |
Action Taken When the DTC Sets
The VCM turns ON the MIL when DTC P0107 is reported and 1 failure has occurred. The VCM substitutes a calculated value for the MAP sensor value so an acceptable driving condition is maintained.
Conditions for Clearing the MIL/DTC
The VCM turns OFF the MIL after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle) or the scan tool clearing feature has been used.
Diagnostic Aids
An intermittent open in the MAP sensor signal circuit or the 5 volt reference circuit will result in a DTC P1107.
With the ignition ON and the engine OFF, the manifold pressure is equal to the atmospheric pressure with the signal voltage high. The VCM uses this information as an indication of the altitude of the vehicle.
Comparison of this reading with a known good vehicle using the same sensor is a good way to check the accuracy of a suspect sensor. Readings should be the same ±0.4 volt.
Important: The electrical connector must remain securely fastened.
Important: After removing the MAP sensor from the intake manifold, replace the MAP Sensor to intake manifold seal.
Remove the MAP sensor. Twist the sensor by hand (only) in order to check for intermittent connections. Output changes greater than 0.1 volt indicates a bad connector or connection.Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if DTC P0107 is the result of a hard failure or an intermittent condition.
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By jumping the 5 volt reference to the signal circuit, this step determines if the sensor is at fault, or if there is a problem with the VCM or wiring.
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The scan tool may not display 5 volts. The important thing is that the VCM recognized the voltage as more than 4 volts, indicating that the VCM and MAP signal circuit are OK.
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The VCM terminals GR 12 and GR 27 are spliced together inside the VCM. When checking the 5 volt reference for a short to ground, both the 5 volt reference circuits and all the components on the 5 volt reference circuits must also be checked.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing DTCs, use the scan tool in order to record freeze frame and the failure records for reference because the Clear Info function will lose the data. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
Does the scan tool display a MAP sensor voltage less than the specified value? | 0.5 V | |||
Does the scan tool display a MAP sensor voltage greater then the specified value? | 4.7 V | |||
Does the scan tool display a MAP sensor voltage greater the specified value? | 4.7 V | |||
5 | The DTC is intermittent. If no additional DTCs are stored, refer to the Diagnostic Aids. If additional DTCs are stored, refer to those tables. | -- | Go to The Applicable DTC Table. | |
6 | Check for a faulty connection at the MAP sensor. Was a problem found? | -- | ||
7 | Check for an open MAP sensor signal circuit. Was a problem found? | -- | ||
8 | Check the MAP sensor signal circuit for a short to ground. Was a problem found? | -- | ||
9 | Check for an open in the MAP sensor 5 volt reference circuit. Was a problem found? | -- | ||
Check for a short to ground in the MAP sensor 5 volt reference circuit. Was a problem found? | -- | |||
11 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Is the action complete? | -- | -- | |
12 | Repair the circuit as necessary. Refer to Wiring Repairs in Engine Electrical. Is the action complete? | -- | -- | |
13 | Replace the VCM. Important: If the VCM is faulty, reprogram the VCM. Refer to VCM Replacement/Programming . Is the action complete? | -- | -- | |
14 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||
15 | Using the scan tool, select the Capture Info and the Review Info. Are any DTCs displayed that have not been diagnosed? | -- | Go to The Applicable DTC Table | System OK |
