P0108
P0108-MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT HIGH
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Manifold Absolute Pressure (MAP) Sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. The MAP Sensor reading gives the Powertrain Control Module (PCM) an indication of the current air pressure within the Intake Manifold. The PCM uses this information to help calculate fuel delivery. The MAP Sensor functions as a typical three wire sensor. The PCM supplies 5 volts to the MAP Sensor on a 5 volt reference circuit and provides a ground on a low reference circuit. The MAP Sensor provides a voltage signal to the PCM on a signal circuit relative to the pressure changes. The PCM receives the Barometric Pressure (BARO) Sensor reading from the MAP Sensor with the ignition on, before the engine is cranking or running.
- When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
- Set Condition:
The Powertrain Control Module (PCM) detects that the Manifold Absolute Pressure (MAP) Sensor input voltage is above the maximum acceptable threshold. One trip fault. If the vehicle is equipped with the stop/start feature, the system will be disabled when this DTC is active.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
Diagnostic Test
1. DTC IS ACTIVE
1. Start the engine and allow it to idle.
WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
2. With the scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.
2. CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the MAP Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (F856) 5-Volt Supply circuit at the Manifold Absolute Pressure Sensor harness connector.
Is the voltage above 5.2 volts?
Yes
- Repair the (F856) 5-Volt Supply circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 3
3. CHECK THE (K1) MAP SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Measure the voltage of the (K1) MAP Signal circuit at the MAP Sensor harness connector.
Is the voltage above 5.2 volts?
Yes
- Repair the (K1) MAP Signal circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 4
4. CHECK FOR THE (K1) MAP SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance between the (K1) MAP Signal circuit and the (F856) 5-Volt Supply at the MAP Sensor harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 5
No
- Repair the (K1) MAP Signal circuit for a short to the (F856) 5 Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
5. CHECK THE (K1) MAP SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K1) MAP Signal between the MAP Sensor harness connector and the PCM C2 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 6
No
- Repair the (K1) MAP Signal for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
6. CHECK THE (K900) SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K900) Sensor Ground circuit between the MAP Sensor harness connector and the PCM C2 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 7
No
- Repair the (K900) Sensor Ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
7. MAP SENSOR
1. Reconnect the PCM C2 harness connector.
2. Connect a jumper between the (K900) Sensor Ground circuit and the (K1) MAP Signal circuit at the MAP Sensor harness connector.
3. Turn the ignition on.
4. With the scan tool, read the MAP Sensor signal voltage.
Is the voltage below 1.0 volt with the jumper in place?
Yes
- Replace the MAP Sensor. Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 8
8. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Manifold Absolute Pressure Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform the Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Replace and program the Powertrain Control Module (PCM). Powertrain Control Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.