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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD (LPG) 🢒 DTC 🢒 DTC P0107

Circuit Description

The manifold absolute pressure (MAP) sensor is a pressure sensor. The powertrain control module (PCM) supplies about 5 volts on the MAP sensor reference voltage circuit. The PCM also supplies a ground circuit to the MAP sensor. When the manifold vacuum is low, the MAP signal voltage rises to near 4.5 volts. As the manifold vacuum increases, the MAP signal voltage drops to around 1 volt. The PCM and the Alternative Fuels ECM monitor the MAP signal circuit voltage and determine the vacuum within the intake manifold.

Certain vehicle models will also use the MAP sensor in order to determine the barometric pressure (BARO) when the ignition switch is turned ON and the engine is NOT cranked. This BARO reading may also be updated whenever the engine is operated at wide open throttle (WOT).

This DTC sets when the MAP sensor signal voltage is below the normal operating range of the sensor.

Conditions for Running the DTC
    • The engine is operating on alternative fuel.
    • The engine speed is greater than 500 RPM.
    • DTCs P0121, P0122, or P0123 are not set.
    • The TP angle is less than 4 percent when engine speed is less than 1,200 RPM.
        or
        The TP angle is greater than 20 percent when engine speed is greater than 1,300 RPM.

Conditions for Setting the DTC

The Alternative Fuel ECM monitors a MAP sensor signal voltage of less than 0.098 volts for at least 4 seconds continuously.

Action Taken When the DTC Sets
    • The Alternative Fuel ECM will switch-over to gasoline fuel operation.
    • The Alternative Fuel ECM will not attempt alternative fuel operation until the next key cycle.
    • A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History.
    • The Alternative Fuels ECM will illuminate the MIL and store the DTC as History after 2 consecutive drive trips that the diagnostic runs and fails.
    • The Alternative Fuels ECM will record operating conditions at the time the DTC sets. This information will be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

    • The Last Test Failed status will clear when the DTC runs and passes.
    • The Alternative Fuels ECM will turn OFF the MIL after 3 consecutive drive trips that the DTC runs and passes.
    • The History status will clear after 40 consecutive WARM-UP cycles with NO failures of ANY DTC.
    • All DTC Information can be cleared with a scan tool.

Test Description

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

  1. This step determines if the condition is present.

    2.

  2. This step determines if the condition affects the PCM.

    3.

  3. This step determines if the MAP sensor is the cause of the condition.

    4.

  4. This step determines if the 5-volt reference circuit is the cause of the condition. 4.8 volts is the minimum output that the PCM should supply on the 5-volt reference circuit.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)

2

  1. Turn OFF the ignition for 30 seconds.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, establish communication with the Alternative Fuels ECM.
  4. Observe and record the MAP Sensor data parameters.
  5. Compare the MAP sensor data display with the MAP sensor values from a known good vehicle.

Do both vehicles display the same MAP sensor data values?

--

Go to Intermittent Conditions

Go to Step 3

3

  1. With a scan tool, establish communication with the PCM.
  2. Observe the MAP Sensor data parameter.

Does the MAP sensor data parameter indicate MAP voltage less than the specified value?

0.2 V

Go to Step 4

Go to Step 10

4

  1. Disconnect the MAP sensor connector.
  2. Jumper the 5-volt reference circuit terminal to the MAP signal circuit terminal using a fused jumper.
  3. Observe the MAP Sensor data parameter.

Does the MAP sensor data parameter indicate MAP voltage greater than the specified value?

4.8 V

Go to Step 12

Go to Step 5

5

  1. Remove the jumper.
  2. Connect the J 39200 DMM between the 5-volt reference circuit terminal and a good ground.
  3. Measure the voltage on the 5-volt reference circuit.

Is the voltage less than the value specified?

4.8 V

Go to Step 8

Go to Step 6

6
  1. Inspect the MAP sensor signal circuit for an open or high resistance between the sensor connector and the PCM.
  2. Inspect for proper terminal contact at both the PCM connector and the MAP sensor connector.
  3. Repair wiring or terminal contact as necessary. Refer to Wiring Repairs or Connector Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 7

7
  1. Inspect the MAP sensor signal circuit for a short to engine ground or to the sensor ground circuit.
  2. Disconnect the Alternative Fuels ECM connector containing the MAP sensor signal circuit in order to determine if the ECM is the cause of the short.
  3. Repair wiring as necessary. Refer to Wiring Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 13

8
  1. Inspect the 5-volt reference circuit for an open or high resistance condition between the sensor connector and the PCM connector terminal.
  2. Inspect for proper terminal contact at both the PCM connector and the MAP sensor connector.
  3. Repair wiring or terminal contact as necessary. Refer to Wiring Repairs or Connector Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 9

9
  1. Inspect all 5-volt reference circuits for a short to ground. Some 5-volt reference circuits are shared within the PCM. The short may be located on either of the 5-volt reference circuits that the PCM provides.
  2. Disconnect the Alternative Fuels ECM connector that contains the 5-volt reference circuit in order to determine if the Alternative Fuels ECM is the cause of the short.
  3. Disconnect the other sensors that are connected to the PCM 5-volt reference circuits in order to determine if a sensor is the cause of the short.
  4. Repair wiring or replace components as necessary.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 13

10

Test the MAP sensor signal circuit for an open between the Alternative Fuels ECM and the splice. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

11

Inspect for proper terminal contact at the harness connector of the Alternative Fuels ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the C/K Pickup Service Manual.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 14

12

Replace the MAP Sensor. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls in the C/K Pickup Service Manual.

Did you complete the replacement?

--

Go to Step 15

--

13

Important: KL6 models require a switchover to gasoline with a scan tool in order to perform the Crankshaft Position Variation Learn Procedure.

KL8 models do not require the Crankshaft Position Variation Learn Procedure.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls in the C/K Pickup Service Manual.

Did you complete the replacement?

--

Go to Step 15

--

14

Replace the Alternative Fuels ECM. Refer to Alternative Fuels Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 15

--

15
  1. Use the scan tool in order to clear the DTCs from the following control modules:
    2. • Alternative Fuels ECM
    • PCM
  2. Turn OFF the ignition for 30 seconds.
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 16

Go to Step 2

16

With a scan tool, select Capture Info in order to observe the stored information.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK