FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Chevy Truck >> 2013 >> Express 4500 V8-6.6L DSL Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0108

P0108




DTC P0107 or P0108

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptors

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

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

Diagnostic Fault Information






Typical Scan Tool Data






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 V to the sensor on the 5 V reference circuit. The ECM supplies a ground on the 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.

Conditions for Running the DTC

* The engine is running for more than 5 s.

* The engine speed is greater than 600 RPM.

* The battery voltage is more than 11 V.

* DTC P0107 and P0108 run continuously when the above enabling conditions are met.

Conditions for Setting the DTC

P0107

The ECM detects that the MAP sensor pressure is less than 45 kPa (7 psi) for 5 s.

P0108

The ECM detects that the MAP sensor pressure is greater than 300 kPa (44 psi) for greater than 5 s.

Action Taken When the DTC Sets

* DTCs P0107 and P0108 are Type B DTCs.

* DPF Regeneration is inhibited.

* The ECM commands Reduced Engine Power mode.

* A message center or an indicator may display Reduced Engine Power.

Conditions for Clearing the DTC

DTCs P0107 and P0108 are Type B DTCs.

Diagnostic Aids

* A wide open throttle (WOT) acceleration from a stop should cause the MAP Sensor parameter on the scan tool to increase rapidly.

* If a shared 5 V reference circuit is shorted to ground or shorted to a voltage, other 5 V reference circuits may be affected.

Reference Information

Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information

Special Tools

J-23738-A - Vacuum Pump

For equivalent regional tools, refer to Special Tools Tools and Equipment.

Circuit/System Verification

1. Verify that DTC P0651 is not set.

• If the DTC sets
If set, refer to DTC P0641, P0651, P0697, P06A3, P06D2, or P06D6 P0641.

• If the DTC does not set

2. If you were sent here from DTC P0068, P0121, or P1101; refer to Circuit/System Testing.

3. Ignition ON.

4. Determine the testing altitude. Verify the scan tool MAP Sensor parameters are within the range specified in the Altitude Versus Barometric Pressure Altitude Versus Barometric Pressure table.

• If the MAP Sensor pressure is not in range
Refer to Circuit/System Testing.

• If the MAP Sensor pressure is within range

5. Engine idling.

6. Slowly increase the engine speed to 2,000 RPM by commanding the throttle valve to open. Then allow the engine speed to return to a stable idle. Verify the scan tool MAP Sensor parameter smoothly increments to a higher value at 2,000 RPM and then returns to near BARO at idle speed.

• If the parameter is not as specified or does not change smoothly
Refer to Circuit/System Testing.

• If the parameter is as specified and does change smoothly

7. 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 data.

8. Verify a DTC does not set.

• If the DTC sets
Refer to Circuit/System Testing.

• If the DTC does not set

9. All OK.

Circuit/System Testing

Note:

* You must perform the Circuit/System Verification before proceeding with the Circuit/System Testing.

* You must perform the Diagnostic Repair Verification after completing the Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the B74 Manifold Absolute Pressure sensor.

2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 2 ohms between the low reference circuit terminal 2 and ground.

• If 2 ohms or greater

1. Ignition OFF, disconnect the X3 harness connector at the K20 Engine Control Module.

2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K20 Engine Control Module.

• If less than 2 ohms

3. Ignition ON.

4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.

• If less than 4.8 V

1. Ignition OFF, disconnect the X3 harness connector at the K20 Engine Control Module.

2. Test for infinite resistance between the 5 V reference circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the 5 V reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K20 Engine Control Module.

Note: If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.

• If greater than 5.2 V

1. Ignition OFF, disconnect the X3 harness connector at the K20 Engine Control Module.

2. Ignition ON, test for less than 1 V between the 5 V reference circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V, replace the K20 Engine Control Module.

• If between 4.8-5.2 V

5. Verify the scan tool MAP Sensor voltage parameter is less than 0.2 V.

• If 0.2 V or greater

1. Ignition OFF, disconnect the X3 harness connector at the K20 Engine Control Module.

2. Ignition ON, test for less than 1 V between the signal circuit terminal 3 and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V, replace the K20 Engine Control Module.

• If less than 0.2 V

6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 1.

7. Verify the scan tool MAP Sensor voltage parameter is greater than 4.5 V.

• If 4.5 V or less

1. Ignition OFF, disconnect the X3 harness connector at the K20 Engine Control Module.

2. Test for infinite resistance between the signal circuit terminal 3 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open or high resistance in the circuit.

• If less than 2 ohms, replace the K20 Engine Control Module.

• If greater than 4.5 V

8. Test or replace the B74 Manifold Absolute Pressure sensor.

Component Testing

Note: You must perform the Circuit/System Testing in order to verify the integrity of the MAP sensor circuits before proceeding with the Component Testing.

Skewed Sensor Test

1. Ignition OFF, remove the B74 Manifold Absolute Pressure sensor from the engine. Connect the harness to the sensor, if disconnected.

2. Ignition ON, observe and note the scan tool MAP Sensor parameter value.

3. Using the first column of the table below, find the table value that is closest to the observed MAP Sensor parameter value.
THEN

4. Connect the EN 23738-A - Mityvac to the sensor.

5. Ignition ON, observe and note the scan tool MAP Sensor parameter value, when performing the following step.

Note: When -17 kPa (5.0 in Hg) vacuum is applied, the MAP Sensor parameter value should change by -17 kPa (-2.5 psi) ±5%.

6. Apply -17 kPa (5.0 inHg) of vacuum to the B74 Manifold Absolute Pressure sensor, with the EN 23738-A - Mityvac. Verify the parameter is within the range of the table's second column, for the table value used in step 3.

• If not within the acceptable range
Replace the B74 Manifold Absolute Pressure sensor.

• If within the acceptable range

7. Ignition ON, observe and note the scan tool MAP Sensor parameter value, when performing the following step.

Note: When -34 kPa (10.0 in Hg) vacuum is applied, the MAP sensor parameter value should change by -34 kPa (-10.0 psi) ±5%.

8. Apply -34 kPa (10.0 inHg) of vacuum to the B74 Manifold Absolute Pressure sensor, with the EN 23738-A - Mityvac, observe and note the scan tool MAP Sensor parameter value. Verify the parameter is within the range of the table's third column, for the table value used in step 3.

• If not within the acceptable range
Replace the B74 Manifold Absolute Pressure sensor.

• If within the acceptable range

9. All OK.






Erratic Signal Test

1. Ignition OFF, remove the B74 Manifold Absolute Pressure sensor and disconnect the harness.

2. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 of the sensor and the sensor harness.

3. Install a jumper wire between the low reference circuit terminal 2 of the sensor and ground.

4. Install a jumper wire to the signal circuit terminal 3 of the sensor.

5. Connect a DMM between the jumper wire and ground.

6. Ignition ON, observe the DC voltage on the DMM. Slowly apply vacuum to the sensor with the EN 23738-A - Mityvac. Verify the voltage changes, without any spikes or dropouts, between 4.9-0.2 V.

• If not between 4.9-0.2 V or has spikes or dropouts
Replace the B74 Manifold Absolute Pressure sensor.

• If between 4.9-0.2 V and there are no spikes or dropouts

7. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Manifold Absolute Pressure Sensor Replacement Service and Repair

* Perform the scan tool Diesel Particulate Filter (DPF) Regeneration Enable Diesel Particulate Filter (DPF) Regeneration Enable procedure if the scan tool DPF Soot Mass is less than 30 g. If the scan tool DPF Soot Mass is greater than 30 g, perform the Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration.

* Control Module References Control Module References for ECM replacement, programming, and setup

pro multis Credits:Operation CHARM About Operation CHARM