1000 - 1999: 1909

1909-MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT HIGH





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and battery voltage greater than 10 volts.

- Set Condition:
The PCM detects that the Manifold Absolute Pressure Sensor input voltage is below the minimum acceptable value.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE

NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.

Turn the ignition on.
With the scan tool, read DTCs.
Record all DTC and applicable Freeze Frame information.
With the scan tool, clear DTCs.
Cycle the ignition off for at least one minute.
Start the engine and allow it to reach operating temperature.

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 fitting clothing. Failure to follow these instructions can result in personal or fatal injury.

With the scan tool, read DTCs.
Does this DTC reset?

Yes

- Go to 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking for an Intermittent DTC

2. MANIFOLD ABSOLUTE PRESSURE SENSOR WIRING AND CONNECTORS
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).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Inspect the Manifold Absolute Pressure Sensor for any condition that would result in an incorrect signal, such as damage, corrosion, or contamination.
Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test.Powertrain Verification Test.

No

- Go to 3

3. 5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE




Turn the ignition off.
Disconnect the Manifold Absolute Pressure Sensor connector.
Disconnect the Powertrain Control Module (PCM) connector.
Turn the ignition on.
Measure the voltage of the 5 Volt Supply circuit in the Manifold Absolute Pressure Sensor harness connector.
Is there any voltage present?

Yes

- Repair the 5 Volt Supply circuit for a short to voltage.
- Perform the PCM Verification Test.Powertrain Verification Test.

No

- Go to 4

4. MAP SIGNAL CIRCUIT SHORTED TO VOLTAGE




Measure the voltage of the MAP Signal circuit in the Manifold Absolute Pressure Sensor harness connector.
Is there any voltage present?

Yes

- Repair the MAP Signal circuit for a short to voltage.
- Perform the PCM Verification Test.Powertrain Verification Test.

No

- Go to 5

5. 5 VOLT SUPPLY CIRCUIT SHORTED TO THE MAP SIGNAL CIRCUIT




Turn the ignition off.
Measure the resistance between the 5 Volt Supply circuit and the MAP Signal circuit in the Manifold Absolute Pressure Sensor harness connector.
Is the resistance above 100 ohms?

Yes

- Go to 6

No

- Repair the 5 Volt Supply circuit for a short to the MAP Signal circuit.
- Perform the PCM Verification Test.Powertrain Verification Test.

6. MAP SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE




Measure the resistance of the MAP Signal circuit between the Manifold Absolute Pressure Sensor harness connector and the Powertrain Control Module (PCM) harness connector.
Is the resistance below 5.0 ohms?

Yes

- Go to 7

No

- Repair the MAP Signal circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test.

7. SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE




Measure the resistance of the Sensor Ground circuit between the Manifold Absolute Pressure Sensor harness connector and the Powertrain Control Module (PCM) harness connector.
Is the resistance below 5.0 ohms?

Yes

- Go to 8

No

- Repair the Sensor Ground circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test.

8. MANIFOLD ABSOLUTE PRESSURE SENSOR
Turn the ignition off.
Connect the Powertrain Control Module (PCM) harness connector.
Replace the Manifold Absolute Pressure Sensor.
Turn the ignition on.
With the scan tool, clear DTCs.
Cycle the ignition off for at least one minute.
Start the engine and allow it to reach operating temperature.

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 fitting clothing. Failure to follow these instructions can result in personal or fatal injury.

With the scan tool, read DTCs.
Does this DTC reset?

Yes

- Go to 9

No

- Test complete.
- Perform the PCM Verification Test.Powertrain Verification Test

9. POWERTRAIN CONTROL MODULE (PCM)
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).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test.Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM Verification Test.Powertrain Verification Test.