P0107

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The PCM uses the Manifold Absolute Pressure (MAP) sensor to control the fuel delivery and the ignition timing. The MAP sensor measures the changes in the intake manifold pressure which results from engine load (intake manifold vacuum) and the RPM changes; and converts these into a voltage outputs. The Powertrain Control Module (PCM) sends a 5 volt reference voltage to the MAP sensor. As the manifold pressure changes, the output voltage of the MAP sensor also changes. By monitoring the MAP sensor output voltage, the PCM knows the manifold pressure. A lower pressure (low voltage) output voltage will be about 1.0 to 1.5 volts at idle. White higher pressures (high voltage) output voltage will be about 4.5 to 4.8 at Wide Open Throttle (WOT). The MAP sensor is also used, under certain conditions, to measure barometric pressure, allowing the PCM to make adjustments for different altitudes.

CONDITIONS FOR SETTING THE DTC

^ MAP is less than 14 kPa.

^ Engine speed is less than 1200 RPM.

OR

^ Throttle Position (TP) is greater than 15% and engine speed is greater than 1200 RPM.

^ Above conditions met for 0.2 seconds. DTC P0122 or P0123 not set.

ACTION TAKEN WHEN THE DTC SETS

^ The Malfunction Indicator Lamp (MIL) will illuminate.

^ The Powertrain Control Module (PCM) will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.

^ A history DTC is stored.

^ Coolant fan turns ON.

^ The PCM will substitute a fixed MAP value and use Throttle Position (TP) to control the fuel delivery (scan tool will not show defaulted value 0.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The MIL will turn OFF after three consecutive ignition cycles in which the diagnostic runs without a fault.

^ A history DTC will clear after 40 consecutive warm up cycles without a fault.

^ DTC(s) can be cleared by using the scan tool.

DIAGNOSTIC AIDS

With the ignition ON and the engine stopped, the manifold pressure is equal to atmospheric pressure and the signal voltage will be high. This information is used by the PCM as an indication of vehicle altitude. Comparison of this reading with a known good vehicle with the same sensor is a good way to check the accuracy of a suspect sensor. Readings should be the same ±0.4 volt.

NOTE:: After repairs use the scan tool Fuel Trim Reset function to reset long term fuel trim to 128 (0%).

If a DTC P0107 is intermittent, refer to Symptoms or to MAP Sensor Output Check for further diagnosis. Testing and Inspection MAP Sensor Output Diagnosis

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records 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.

2. This step determines if DTC P0107 is the result of a hard failure or an intermittent condition.

3. Jumping harness terminals B to C (signal circuit to 5 volts) will determine if the sensor is at fault or if there is a problem with the PCM or wiring.

6. The scan tool may not display 5 volts. The important thing is that the PCM recognizes the voltage as more than 4 volts, indicating that the PCM and CKT 432 are OK. A test light that illuminates indicates a short to ground in the signal circuit.

7. An open or short to ground in CKT 416 could also set additional DTC's.