Circuit Description
VIN K
The manifold absolute pressure (MAP) sensor responds to changes in the intake manifold pressure. The PCM supplies a 5-volt reference and a ground for the MAP sensor. The MAP sensor provides a signal to the powertrain control module (PCM) relative to the pressure changes in the manifold. The MAP sensor signal voltage to the PCM varies from less than 2 volts at idle, or a low MAP and a high vacuum, to more than 4 volts with the key ON, and with the engine not running or at wide-open throttle, and a high manifold absolute pressure and a low vacuum. The PCM monitors the MAP signals for voltages outside the normal range of the MAP sensor. If the PCM detects a MAP signal voltage that is excessively high, DTC P0108 will set.
VIN 1
The MAP sensor responds to changes in the intake manifold pressure. The PCM supplies a 5-volt reference and a ground for the MAP sensor. The MAP sensor provides a signal to the PCM relative to the pressure changes in the manifold. With the key ON, and with the engine not running, the MAP sensor signal voltage to the PCM varies between 1.5 volts and 2.5 volts. With the engine running, the MAP sensor voltage to the PCM varies from less than 2 volts at idle, or a low manifold absolute pressure and a high vacuum, to more than 4 volts at wide-open throttle, or a high manifold absolute pressure and a low vacuum. The PCM monitors the MAP signals for voltage outside the normal range of the MAP sensor. If the PCM detects a MAP signal voltage that is excessively high, DTC P0108 will set.
Conditions for Running the DTC
| • | No throttle position (TP) sensor DTCs are present. |
| • | The engine has been running an interval that is determined by the start-up coolant temperature. The time ranges from 2 minutes at less than -30° C (-22° F) to 0.5 second at more than 30°C (86°F). |
| • | The idle speed is steady. |
| • | The throttle position is less than 2 percent. |
| • | The engine speed is less than 900 RPM. |
Conditions for Setting the DTC
| • | The MAP sensor signal voltage is more than 4.2 volts. |
| • | The above conditions are present for more than 200 3X reference periods, or 67 crankshaft revolutions. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
Inspect for the following conditions:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 |
Important: If DTC P1635 5 Volt Reference Circuit is set, perform that diagnostic first.
Is the voltage more than the specified value? | 4.2 V | ||
3 |
Does the DTC reset? | -- | Go to Diagnostic Aids | |
4 |
Is the voltage at the specified value? | 0 V | ||
5 | Inspect for a plugged or leaking vacuum supply to the MAP sensor. Did you find and correct the condition? | -- | ||
6 | Test the ground circuit of the MAP sensor for continuity. Refer to Circuit Testing in Wiring Systems. If you find a problem repair the condition as necessary. Did you find and correct the condition? | -- | ||
7 | Test the signal circuit of the MAP sensor for a short to voltage or for a short to the 5-volt reference A circuit. Repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
8 | Inspect the ground circuit of the MAP sensor at the MAP sensor for faulty connections at the harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
9 | Inspect the ground circuit of the MAP sensor at the PCM for a faulty connection at the harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
10 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the replacement? | -- | -- | |
11 |
Important: You must program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | -- | |
12 |
Does the DTC reset? | -- | System OK |
