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P1185






P1185-GENERAL PRESSURE SENSOR CORRELATION

For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
With the ignition on.

- Set Condition:
The Powertrain Control Module (PCM) compares the Throttle Inlet Pressure Sensor, MAP Sensor and BARO Sensor values. If two sensors are within a specific range of each other and another is not, the value outside of the specified range is declared irrational. Two trip fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. DTC IS ACTIVE

NOTE: Diagnose and repair any Throttle Inlet Pressure or MAP Sensor DTCs before proceeding with this test.

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

1. Start the engine and allow it to reach normal 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 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 CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. Intermittent Condition Test.

2. CHECKING THE MAP SENSOR
1. Perform the diagnostic procedure for CHECKING THE MAP SENSOR OPERATION. Checking The MAP Sensor Operation.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. CHECKING THE BAROMETRIC PRESSURE SENSOR

NOTE: The Barometric Pressure Sensor is internal to the PCM.

NOTE: The Barometric Pressure should be approximately equal to the actual barometric pressure. If necessary, compare the Barometric Pressure value of the tested vehicle to the value of a known good vehicle of a similar make and model.

1. Compare the Barometric Pressure of the tested vehicle to the value of a known good vehicle of a similar make and model.

Is the Barometric Pressure value of the tested vehicle equal to the value of the know good vehicle (plus or minus 2%)?

Yes

- Go To 4

No

- Go To 17

4. CHECK THE (F856) 5 VOLT SUPPLY CIRCUIT VOLTAGE
1. Turn the ignition off.
2. Disconnect the Throttle Inlet Pressure Sensor harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (F856) 5 Volt Supply circuit at the Throttle Inlet Pressure Sensor harness connector.

NOTE: The voltage should be 5.0 Volts (plus or minus 0.1 of a Volt).

Is the voltage displayed as described above?

Yes

- Go To 5

No

- Go To 12

5. CHECK FOR THE (F856) 5 VOLT SUPPLY CIRCUIT SHORTED TO THE (K37) TIP SIGNAL CIRCUIT
1. Disconnect the Powertrain Control Module (PCM) harness connectors.
2. Measure the resistance between the (F856) 5 Volt Supply circuit and the (K37) TIP Signal circuit at the Throttle Inlet Pressure Sensor harness connector.

Is the resistance above 100 Ohms?

Yes

- Go To 6

No

- Repair the (F856) 5 Volt Supply circuit for a short to the (K37) TIP Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. CHECK THE (K37) TIP SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition on.
2. Measure the voltage of the (K37) TIP Signal circuit at the Throttle Inlet Pressure Sensor harness connector.

Is there any voltage present?

Yes

- Repair the (K37) TIP Signal circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 7

7. Check The (K37) TIP SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Measure the resistance between ground and the (K37) TIP Signal circuit at the Throttle Inlet Pressure Sensor harness connector.

Is the resistance above 100 Ohms?

Yes

- Go To 8

No

- Repair the (K37) TIP Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

8. CHECK FOR THE (K37) TIP SIGNAL CIRCUIT SHORTED TO THE (K900) TIP RETURN CIRCUIT
1. Measure the resistance between the (K37) TIP Signal circuit and the (K900) TIP Return circuit at the Throttle Inlet Pressure Sensor harness connector.

Is the resistance above 100 Ohms?

Yes

- Go To 9

No

- Repair the (K37) TIP Signal circuit for a short to the (K900) TIP Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

9. CHECK THE (K37) TIP SIGNAL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE

NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact.

1. Measure the resistance of the (K37) TIP Signal circuit between the Throttle Inlet Pressure Sensor harness connector and the Powertrain Control Module (PCM) harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 10

No

- Repair the (K37) TIP Signal circuit for an open circuit or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

10. CHECK THE (K900) TIP RETURN CIRCUIT FOR AN OPEN OR HIGH RESISTANCE

NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact.

1. Measure the resistance of the (K900) TIP Return circuit between the Throttle Inlet Pressure Sensor harness connector and the Powertrain Control Module (PCM) harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 11

No

- Repair the (K900) TIP Return for an open circuit or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

11. CHECK THE THROTTLE INLET PRESSURE SENSOR SIGNAL VOLTAGE
1. Turn the ignition off.
2. Connect the Powertrain Control Module (PCM) harness connectors.
3. Connect a jumper wire between the (K900) TIP Return circuit and the (K37) TIP Signal circuit at the Throttle Inlet Pressure Sensor harness connector.
4. Turn the ignition on.
5. With the scan tool, read the Throttle Inlet Pressure Sensor signal voltage.

NOTE: The voltage should be 0.0 Volts (plus or minus 0.1 of a Volt) with the jumper wire in place.

Is the voltage on the scan tool displayed as described above?

Yes

- Go To 16

No

- Go To 17

12. CHECK THE (F856) 5 VOLT SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (F856) 5 Volt Supply circuit at the Throttle Inlet Pressure Sensor harness connector.\

Is there any voltage present?

Yes

- Repair the (F856) 5 Volt Supply circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 13

13. CHECK THE (F856) 5 VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Measure the resistance between ground and the (F856) 5 Volt Supply circuit at the Throttle Inlet Pressure Sensor harness connector.

Is the resistance above 100 Ohms?

Yes

- Go To 14

No

- Repair the (F856) 5 Volt Supply circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

14. CHECK FOR THE (F856) 5 VOLT SUPPLY CIRCUIT SHORTED TO THE (K900) TIP RETURN CIRCUIT
1. Measure the resistance between the (F856) 5 Volt Supply circuit and the (K900) TIP Return circuit at the Throttle Inlet Pressure Sensor harness connector.

Is the resistance above 100 Ohms?

Yes

- Go To 15

No

- Repair the (F856) 5 Volt Supply circuit for a short to the (K900) TIP Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

15. CHECK THE (F856) 5 VOLT SUPPLY CIRCUIT FOR AN OPEN OR HIGH RESISTANCE

NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact.

1. Measure the resistance of the (F856) 5 Volt Supply circuit between the Throttle Inlet Pressure Sensor harness connector and the Powertrain Control Module (PCM) harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 17

No

- Repair the (F856) 5 Volt Supply circuit for an open circuit or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

16. THROTTLE INLET PRESSURE SENSOR
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Inlet 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. Verify that there is good pin to terminal contact in the related connectors.
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 any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace the Throttle Inlet Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

17. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP Sensor and the Powertrain Control Module (PCM) and between the Throttle Inlet 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 any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace the Powertrain Control Module (PCM).
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

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