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 sensor signal circuit. This voltage signal will vary from 1.0-1.5 volts at closed throttle to 4.0-4.6 volts at wide open throttle (low vacuum). The VCM utilizes the MAP signal and the throttle position in order to determine the correct amount of fuel delivered to the engine. This DTC is a type D DTC.
Conditions for Setting the DTC
The following conditions will set the DTC:
- No TP sensor faults are set.
- The engine is operating.
- The TP is at least 0% when engine speed is no more than 800 RPM.
- Or the TP is at least 12.5% when the engine speed is greater than 800 RPM.
- The MAP voltage less than 0.20 volts.
Action Taken When the DTC Sets
The VCM turns the MIL ON when this DTC is reported and 1 failure has occurred. The VCM substitutes a calculated value for the MAP sensor value so that acceptable performance is maintained.
Conditions for Clearing the MIL/DTC
A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 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 ±4 volt.
Refer to Intermittent Conditions .
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.
Disconnect the sensor from the bracket. Twist the sensor by hand (only) in order to check for intermittent connections. The output changes greater than 0.1 volt indicates a bad connector or connection. If OK, replace the sensor. Refer to MAP Sensor Replacement .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if the DTC P1107 is the result of a hard failure or an intermittent condition.
-
Jumpering the 5 volt reference to the signal circuit will determine if sensor is at fault or if there is a problem with the VCM, or the wiring.
-
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 sensor signal circuit are OK.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool to record the Freeze Frame and the Failure Records for reference. This data will be lost when the Clear Info function is used. 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 | |||
Turn ON the ignition. 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 first. Are any additional DTCs stored? | -- | 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? | -- | ||
10 | Check for a short to ground in the MAP sensor 5 volt reference circuit. Was a problem found? | -- | ||
11 | Replace the faulty MAP sensor. Refer to MAP 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 faulty VCM. Important: If the VCM is faulty, the new VCM must be programmed. 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 |
