Powertrain Management (Heavy Duty L96)
DTC P0107 or P0108 (Heavy Duty L96)
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 provides 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 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 V to the sensor on a 5 V 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 to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 10 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.
Conditions for Running the DTC
P0107
This DTC runs continuously.
P0108
This DTC runs continuously.
Conditions for Setting the DTC
P0107
The ECM detects that the MAP sensor voltage is less than 0.15 V for greater than 4 s.
P0108
The ECM detects that the MAP sensor voltage is greater than 4.90 V for greater than 4 s.
Action Taken When the DTC Sets
DTCs P0107 and P0108 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0107 and P0108 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics (except L96) [1][2]Electrical DiagramsEngine Controls Schematics (L96) [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 - Mityvac
* J-35555 - Metal Mityvac
Circuit/System Verification
Note:
A skewed MAP sensor will also cause the first and second intake manifold models to disagree with the actual MAP sensor measurements. Use the scan tool and compare the MAP Sensor parameter to a known good vehicle under various operating conditions. The readings should be within 3 kPa of the known good vehicle.
1. If DTC P0641, P0651, P0697, or P06A3 are set, refer to DTC P0641, P0651, P0697, or P06A3 (ECM, L96) Powertrain Management (ECM, L96).
2. Ignition OFF for 90 s, determine the current vehicle testing altitude. Ignition ON, observe the scan tool BARO Sensor parameter. Compare the parameter to the Altitude Versus Barometric Pressure Altitude Versus Barometric Pressure table. The BARO sensor pressure parameter should be within the specified range indicated in the table.
3. Ignition ON, observe the scan tool MAP sensor parameter. Start the engine. The MAP Sensor parameter should change.
Circuit/System Testing
1. Verify the integrity of the air induction system by inspecting for the following conditions:
* Any damaged components
* Loose or improper installation
* Improperly routed vacuum hoses
* Any vacuum leak
* Any type of restriction
* MAP sensor seal that is missing or damaged
2. Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust Restricted Exhaust.
3. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Disconnect the MAP harness connector at the MAP sensor.
4. Test for less than 5 ohms between the low reference circuit terminal 2 and ground.
• If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
5. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.
• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
• If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
6. Verify the scan tool MAP Sensor parameter is less than 12 kPa.
• If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM.
7. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 1. Verify the scan tool MAP Sensor parameter is greater than 103 kPa.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
8. If all circuits test normal, test or replace the MAP 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. Using the following steps and referencing the table below will determine if the MAP sensor is skewed.
2. Ignition ON, engine OFF, observe the MAP sensor scan tool parameter.
3. Use the observed MAP Sensor Scan Tool parameter that is closest to a value that is indicated in the first column.
4. Using the J-23738-A - Mityvac or the J-35555 - Metal Mityvac to apply 5 in Hg of vacuum to the MAP sensor, the parameter in the first column should decrease by 17 kPa. The acceptable range is indicated in the second column.
5. Using the J-23738-A - Mityvac or the J-35555 - Metal Mityvac to apply 10 in Hg of vacuum to the MAP sensor, the parameter in the first column should decrease by 34 kPa. The acceptable range is indicated in the third column.
Erratic Signal Test
1. Ignition OFF, remove the MAP sensor.
2. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 and the corresponding terminal of the MAP sensor.
3. Install a jumper wire between the low reference terminal 2 of the MAP sensor and ground.
4. Install a jumper wire at terminal 3 of the MAP sensor.
5. Connect a DMM between the jumper wire from the terminal 3 of the MAP sensor and ground.
6. Ignition ON, with the J-23738-A - Mityvac or J-35555 - Metal Mityvac, slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 4.9-0.2 V without any spikes or dropouts.
• If the voltage is erratic, replace the MAP sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Manifold Absolute Pressure Sensor Replacement Service and Repair
* Control Module References Control Module References for ECM replacement, setup, and programming