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Home >> Hummer >> 2006 >> H1 V8-6.6L DSL Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0108

P0108



DTC P0108

DTC DESCRIPTORS

DTC P0107
DTC P0107 Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage

DTC P0108
DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage

DIAGNOSTIC FAULT INFORMATION






IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

TYPICAL SCAN TOOL DATA

MAP Sensor, KPa:




MAP Sensor, Volts:






CIRCUIT/SYSTEM DESCRIPTION
The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by turbocharger output, engine speed, accelerator pedal input, 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 engine control module (ECM) supplies a regulated 5 volts to the sensor on a 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 lowest pressure that can exist in the intake manifold is equal to the BARO. This occurs when the vehicle is operating at idle or when the ignition is ON, while the engine is OFF. The ECM uses the MAP sensor to aid in diagnosis of the turbocharger performance. The highest manifold pressures occur when the turbocharger output is high. Manifold pressure can range from 58 kPa (8 psi) when pressure are low, to more than 240 kPa (34 psi) when pressures are high, depending on the BARO. The MAP sensor has a range of 33-255 kPa (4-36 psi).

CONDITIONS FOR RUNNING THE DTC
- The engine is running for more than 1 second.
- The engine speed is between 500-2,500 RPM.
- The ignition 1 voltage is more than 11 volts.
- The above conditions are met for more than 2 second.
- DTC P0107 and P0108 run continuously within the enabling conditions.

CONDITIONS FOR SETTING THE DTC

P0107
The MAP voltage is less than 0.2 volt for 2 seconds.

P0108
The ECM detects that the MAP voltage is more than 4.1 volts for more than 2 seconds.

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.

SPECIAL TOOLS REQUIRED
J 36169-A Fused Jumper Wire

CIRCUIT/SYSTEM VERIFICATION
1. If DTCs P0698 or P0699 are set, diagnose those codes first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle.

IMPORTANT: If you cannot duplicate the condition, 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.

2. Verify the integrity of the air induction system by inspecting for the following conditions:
- Damaged components
- Loose or improper installation
3. Turn ON the ignition, with the engine OFF, and use a scan tool to observe the MAP and BARO parameters.
- If the MAP and BARO sensor parameters do not match continue with this diagnostic.
4. Verify that any electrical aftermarket devices are properly connected and grounded. Refer to Checking Aftermarket Accessories.

CIRCUIT/SYSTEM TESTING

P0107
1. With the ignition ON, the engine OFF, and the MAP sensor disconnected, use a DMM and measure for a voltage range of 4.8-5.1 volts between the MAP sensor 5-volt reference circuit and a good ground.
- If the voltage is less than 4.8 volts, then test the 5-volt reference circuit for an open, high resistance, or short to ground.
2. Connect a 3-amp J 36169-A between the 5-volt reference voltage circuit of the MAP sensor and the signal circuit of the MAP sensor. With a scan tool, observe the MAP Sensor parameter for a value of more than 250 kPa or 4.8 volts.
- If the MAP Sensor parameter is not more than 250 kPa or 4.8 volts, test the signal circuit for an open, a short to ground or a faulty ECM.
- If the MAP Sensor parameter is more than 250 kPa or 4.8 volts, replace the MAP sensor.

P0108
1. With the ignition ON, the engine OFF, and the MAP sensor disconnected, use a DMM and measure for a voltage of less than 0.4 volt between the MAP sensor signal circuit and a good ground.
- If the voltage is more than 0.4 volt, test the signal circuit for a short to voltage or a faulty ECM.
2. Turn OFF the ignition, and all electrical accessories. Allow 60 seconds for the control module to power down before proceeding and before taking a resistance measurement. Measure the resistance of the low reference circuit at the MAP sensor connector with a DMM connected to a good ground.
- If the resistance is more than 2 ohms, then test the circuit for a high resistance or a faulty ECM.
- If the MAP sensor circuits test normal, then replace the MAP sensor.

IMPORTANT: The DMM and test leads must be calibrated to 0 ohms in order to prevent misdiagnosis. Use the DMM to perform this test. Refer to the DMM User Manual for the calibration procedure.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Manifold Absolute Pressure (MAP) Sensor Replacement
- Control Module References for ECM replacement, setup, and programming
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