DTC P0107. Cadillac STS 2005

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 Accessories 🢒 Navigation Systems 🢒 DTC P0107

Circuit Description

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on the 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation the highest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is on while the engine is off. Under these conditions, the ECM uses the MAP sensor in order to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 19 kPa when pressures are low, to as much as 104 kPa when pressures are high, depending on the BARO.

The ECM monitors the MAP sensor signal for pressure outside of the normal range. If the ECM detects that the MAP sensor pressure is excessively low, DTC P0107 sets.

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 ignition is ON.

Conditions for Setting the DTC

•	The ECM detects that the MAP sensor pressure is less than 20 kPa for more than 1 second.

•	DTC P0107 runs continuously once the above conditions are met.

Action Taken When the DTC Sets

•	The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

•

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

•	The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

•	A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

•	A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

•	Clear the MIL and the DTC with a scan tool.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

The measurement noted in this step will be used in subsequent steps if the measurement is not less than the specified value.

This step calculates the resistance in the 5-volt reference circuit.

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

Start the engine.
Monitor the DTC Information with the scan tool.

Is DTC P0641 also set?

Go to DTC P0641

Go to Step 3

Observe the MAP Sensor parameter with the scan tool.

Is the pressure less than the specified value?

20 kPa

Go to Step 5

Go to Step 4

Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 5

Go to Intermittent Conditions

Test for an intermittent and for a poor connection at the manifold absolute pressure (MAP) sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 6

Turn OFF the ignition.
Disconnect the MAP sensor electrical connector.
Turn ON the ignition, with the engine OFF.
Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Note the measurement as supply voltage.

Is the voltage more than the specified value?

4.8 V

Go to Step 7

Go to Step 9

Connect a test lamp and a DMM in series between the 5-volt reference circuit and the low reference circuit of the MAP sensor at the harness connector.
Measure the amperage with the DMM. Note the measurement as amperage.
Remove the DMM from the circuit.
Connect the test lamp between the 5-volt reference circuit and the low reference circuit of the MAP sensor at the harness connector.
Measure the voltage from the 5-volt reference circuit at the test lamp to a good ground, with the DMM. Note the measurement as load voltage drop.

Important: Before any calculations are performed, ensure that all measurements are converted to like units. For example, volts/amps or millivolts/milliamps.

Subtract the load voltage drop from the supply voltage. Note the result as supply voltage drop.
Divide the supply voltage drop by the amperage.

Is the result more than the specified value?

5 ohms

Go to Step 10

Go to Step 8

Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the MAP sensor and the signal circuit of the MAP sensor.
Observe the MAP sensor parameter with the scan tool.

Is the pressure more than the specified value?

103 kPa

Go to Step 13

Go to Step 11

Test the 5-volt reference circuit between the engine control module (ECM) and the MAP sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 12

Test the 5-volt reference circuit between the ECM and the MAP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 12

Test the MAP sensor signal circuit between the ECM and the MAP sensor for the following conditions:

•	A short to ground

•

An open

•	High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 12

Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 14

Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement .

Did you complete the replacement?

Go to Step 15

Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 15

Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 16

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

System OK