C7 and C9 Marine Engines Caterpillar

Use this procedure to troubleshoot any suspect problems with the injection actuation pressure sensor.

This procedure covers the 164-02 Injector Actuation Pressure signal erratic.

Note: This procedure can check the accuracy of the injection actuation pressure sensor against a pressure gauge.

The injection actuation pressure sensor measures the pressure of the oil in the high pressure oil manifold. The high pressure oil in the manifold is used to actuate the injectors and the high pressure oil is used to control the fuel injection pressure. The Electronic Control Module (ECM) uses the reading from the injection actuation pressure sensor in order to control the operation of the injection actuation pressure control valve.

Illustration 1	g01230041
Schematic for the injection actuation pressure sensor

Test Step 1. Check for Active Diagnostic Codes

1. Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to electronic troubleshooting Troubleshooting, "Electronic Service Tools".

2. Restore the electrical power to the ECM.

3. Observe the "Active Diagnostic" screen on Cat ET. Wait at least 30 seconds so that any codes may become active. Look for an active 164-02 diagnostic code.

   Note: If one of the following diagnostic codes is active, refer to the diagnostic functional test Troubleshooting, "Engine Pressure Sensor Open or Short Circuit - Test".

   • 164-03 Injector Actuation Pressure voltage high

   • 164-04 Injector Actuation Pressure voltage low

Expected Result:

The 164-02 diagnostic code is active.

Results:

• Active code - The 02 diagnostic code is active. Proceed to Test Step 3.

• No active code - The 02 diagnostic code is not active. Proceed to Test Step 2.

Test Step 2. Try to Start the Engine

Try to start the engine.

Expected Result:

The engine starts.

Results:

• OK - The engine starts. There are no active codes for the injection actuation pressure sensor and the engine starts.

  Repair: There may be an intermittent problem in a harness that is causing the code to be logged. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - The engine does not start.

  Repair: Refer to troubleshooting without a diagnostic code Troubleshooting, "Engine Cranks but Will Not Start".

  STOP

Test Step 3. Inspect the Electrical Connectors and the Wiring

1. Remove the electrical power from the ECM.

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Illustration 2	g01180781
Typical left side view (1) Injection actuation pressure sensor

2. Thoroughly inspect the J2/P2 ECM connectors. Thoroughly inspect the connector for the injection actuation pressure sensor. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

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Illustration 3	g01180788
P2 terminals that are associated with the injection actuation pressure sensor (P2-17) Return (P2-72) +5 VDC (P2-85) Injection Actuation pressure

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Illustration 4	g01123211
Harness connector for the injection actuation pressure sensor (A) Supply (B) Return (C) Signal

3. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the injection actuation pressure sensor.

4. Check the torque of the allen head screws for the ECM connectors. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

5. Check the harness and wiring for abrasion and for pinch points from the sensor back to the ECM.

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.

Results:

• OK - The connectors and wiring are OK. Proceed to Test Step 4.

• Not OK - There is a problem in the wiring and/or a connector.

  Repair: Repair the wiring and/or the connector. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the problem is resolved.

  STOP

Test Step 4. Check the Status of the Sensor

1. Restore the electrical power to the ECM.

2. Check the value of the "Injection Actuation Pressure" on Cat ET.

   Note: The following codes will cause the value of the "Injection Actuation Pressure" to revert to a default value.

   • 03 Injector Actuation Pressure voltage high

   • 04 Injector Actuation Pressure voltage low

Expected Result:

The value of the "Injection Actuation Pressure" is 0 kPa (0 psi).

Results:

• OK - The value of the "Injection Actuation Pressure" is 0 kPa (0 psi). Proceed to Test Step 6.

• Not OK - The value of the "Injection Actuation Pressure" is above 0 kPa (0 psi). Proceed to Test Step 5.

Test Step 5. Check the Voltage Supply to the Injection Actuation Pressure Sensor

1. Remove the electrical power from the ECM.

2. Disconnect the injection actuation harness connector.

3. Connect a 3-terminal breakout T to the injection actuation harness connector only.

4. Restore the electrical power to the ECM.

5. Measure the voltage between terminals A and B at the breakout T.

Expected Result:

The voltage reading is 5 ± 0.2 VDC.

Results:

• OK - The voltage is within the specified range. Proceed to Test Step 6.

• Not OK - The voltage is not within the specified range.

  Repair: Refer to the diagnostic functional test Troubleshooting, "Analog Sensor Supply Circuit - Test".

  STOP

Test Step 6. Compare the Sensor's Output to a Pressure Gauge

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact the skin.

1. Remove the electrical power from the ECM.

2. Install a 8T-0852 Pressure Gauge to an oil port on the side of the cylinder head or to the port on the top of the fuel transfer pump.

3. Start the engine.

4. Go to the "Injection Actuation Pressure Test" on the diagnostic menu of Cat ET.

5. Start the "Injection Actuation Pressure Test".

6. Refer to Table 1. Observe the value of the "Injection Actuation Pressure" on Cat ET. Vary the engine speed in order to obtain each "Injection Actuation Pressure" value that is listed in the Table. For each pressure value, observe the reading on the pressure gauge.
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   Table 1

   Comparison of Pressure Readings
   "Injection Actuation Pressure" Values on Cat ET	Range of Acceptable Pressure Values on the Pressure Gauge
   6000 kPa (870 psi)	4000-7800 kPa (580-1130 psi)
   10000 kPa (1450 psi)	8000-11800 kPa (1160-1710 psi)
   15000 kPa (2175 psi)	13000-16800 kPa (1885-2435 psi)
   23000 kPa (3336 psi)	21000-24800 kPa (3045-3595 psi)

Expected Result:

Each value on the pressure gauge is within the specification.

Results:

• OK - Each value on the pressure gauge is within the specification. The injection actuation pressure sensor and the ECM are working properly.

  Repair: The problem appears to be resolved. The original diagnostic code was probably caused by an intermittent problem in an electrical connector. If the code continues to be logged, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - At least one of the values on the pressure gauge is not within the specification.

  Repair: Install a new injection actuation pressure sensor and repeat the test.If the new sensor corrects the problem, leave the new sensor in place.If the new sensor does not correct the problem, the pressure gauge is faulty. Obtain a new pressure gauge and repeat the test.

  STOP