Circuit Description
The engine oil pressure sensor is a solid state transducer. The engine oil pressure sensor sends oil pressure information to the PCM. The PCM then transmits the oil pressure information to the IPC via serial data (CKT 1807).
Engine oil pressure is displayed on the scan tool in volts. A low voltage reading indicates low oil pressure. As the oil pressure increases, the voltage level also increases. The normal range of the engine oil level sensor signal voltage is 0.5 volts at 0 kPa (0 psi) to 4.5 volts at 883 kPa (128 psi).
Diagnostic Aids
For diagnosis of the instrument panel, refer to the Instrument Panel System Check in Electrical Diagnosis section 8A-81.
Check for the following conditions:
| • | Poor connection at the PCM or the engine oil pressure sensor. |
| Inspect harness connectors for the following conditions: |
| - | Backed out terminals. |
| - | Improper mating. |
| - | Broken locks. |
| - | Improperly formed or damaged terminals. |
| - | Poor terminal to wire connection. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. |
| • | Instrument panel cluster. |
| The Engine Oil Pressure Sensor diagnostic table is intended to isolate electrical faults that affect the engine oil pressure sensor, the PCM, and related circuits. If a problem with engine oil pressure can not be isolated using the Engine Oil Pressure Sensor diagnostic table, refer to the Instrument Cluster System Check in Electrical Diagnosis. |
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
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Normal engine oil pressure sensor signal voltage is between 0.5 volt at 0 kPa (0 PSI) and 4.5 volts at 883 kPa (128 PSI). If engine oil pressure sensor voltage is within range, determine the cause of incorrect oil pressure. Refer to Engine Mechanical Diagnosis in Engine General Information.
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If the engine oil pressure signal voltage stays high with the engine oil pressure sensor electrical connector disconnected, the signal circuit is shorted to voltage or the PCM is malfunctioning.
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This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
|
Important: Ensure that the engine oil level on the oil level indicator is correct.
Does the scan tool indicate EOP Sensor voltage less than the specified value? | 0.4 V | |||||||||
Does the scan tool indicate EOP Sensor voltage greater than the specified value? | 4.0 V | |||||||||
Disconnect the engine oil pressure sensor while observing EOP Sensor on the scan tool. Does the scan tool indicate EOP Sensor voltage at the specified value? | 0 V | |||||||||
5 |
Does the scan tool indicate EOP Sensor voltage near the specified value? | 5 V | ||||||||
6 | Using a J 39200 Digital Multimeter, measure voltage between the 5 volt reference A circuit and the sensor ground circuit at the engine oil pressure sensor harness connector. Is voltage near the specified value? | 5 V | ||||||||
7 | Check for a poor 5 volt reference A circuit terminal connection at the PCM. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | ||||||||
8 | Check for an open in the 5 volt reference A circuit. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | ||||||||
9 | Check the engine oil pressure signal circuit for a poor terminal connection at the PCM. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | ||||||||
10 | Check the engine oil pressure signal circuit between the engine oil pressure sensor connector and the PCM for an open or short to ground. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | ||||||||
11 | Check the engine oil pressure signal circuit between the engine oil pressure sensor connector and the PCM for a short to voltage. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | ||||||||
12 | Check for a short to voltage on the 5 volt reference A circuit. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | ||||||||
13 | Check for a poor sensor ground circuit terminal connection at the PCM. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | ||||||||
14 | Check for a poor sensor ground circuit terminal connection at the engine oil pressure sensor connector. Was a problem found? | -- | ||||||||
15 | Check for an open in the sensor ground circuit. Refer to Troubleshooting Procedures in Electrical Diagnosis. Was a problem found? | -- | ||||||||
16 | Check the following circuits for a poor connection at the engine oil pressure sensor. Refer to Troubleshooting Procedures in Electrical Diagnosis.
Was a problem found? | -- | ||||||||
17 | Replace the malfunctioning harness connector terminal. Refer to Repair Procedures in Electrical Diagnosis. Is action complete? | -- | -- | |||||||
18 | Locate and repair open/short circuit in wiring harness as necessary. Refer to Repair Procedures in Electrical Diagnosis. Is action complete? | -- | -- | |||||||
19 |
Is oil pressure measured with a gauge near the oil pressure that was observed on the IPC? | -- | Refer to Engine Mechanical Diagnosis in Engine General Information Section 6 | |||||||
20 |
Was a problem found? | -- | ||||||||
21 | Replace the engine oil pressure sensor. Refer to Engine Oil Pressure Sensor . Is action complete? | -- | -- | |||||||
Replace the PCM. Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is action complete? | -- | -- | ||||||||
23 |
Does the scan tool indicate EOP Sensor voltage near the specified value? | 0.5V | ||||||||
24 |
Does the scan tool indicate EOP Sensor voltage greater than the specified value? | 4.4V | System OK |
