3126E On-highway Engine Caterpillar

Use this procedure to troubleshoot the system when the following diagnostic code is active:

• 164-02 Injection Actuation Pressure Signal Erratic (15)

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

The following background information is related to the following procedure:

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. Fuel injection pressure is based on inputs from the sensors. The inputs are used by the ECM for calculating the fuel injection pressure. The 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	g00862894
Location of the injection actuation pressure control valve

Illustration 2	g00725355
Schematic for the injection actuation pressure sensor

Illustration 3	g00725426
Locations for the ECM terminals on connector P2

Test Step 1. Check for Active Diagnostic Codes

1. Connect the Caterpillar Electronic Technician (Cat ET) to the data link connector.

2. Turn the key switch to the ON position.

   Note: If the 164-02 Injection Actuation Pressure Signal Erratic (15) is not active or logged, try to start the engine.

   Note: If 164-03 Injection Actuation Pressure Voltage High (15) or 164-04 Injection Actuation Pressure Voltage Low (15) is active, refer to Troubleshooting, "Engine Pressure Sensor Open or Short Circuit-Test".

Expected Result:

164-02 Injection Actuation Pressure Signal Erratic is active.

Results:

• Yes - The engine will not start. 164-02 Injection Actuation Pressure Signal Erratic is active. Proceed to Test Step 2.

• No - The engine will not start. 164-02 Injection Actuation Pressure Signal Erratic is not active. Proceed to Test Step 2.

• No - 164-02 is not active. The engine starts. The system is operating correctly at this time.STOP

Test Step 2. Disconnect the Injection Actuation Pressure Sensor and Start the Engine

1. Turn the key switch to the OFF position.

2. Disconnect the electrical connector J204/P204 for the injection actuation pressure sensor from the engine harness.

3. Try to start the engine.

Expected Result:

The engine starts.

Results:

• Yes - Proceed to Test Step 3.

• No -

  Repair: Reconnect the electrical connector J204/P204 for the injection actuation pressure sensor to the engine harness. Refer to Troubleshooting, "Engine Cranks but Will Not Start".

  STOP

Test Step 3. Inspect Electrical Connectors and Wiring

1. Thoroughly inspect the connector J204/P204 for the injection actuation pressure sensor and inspect the ECM engine harness connector J2/P2. Refer to Troubleshooting, "Electrical Connectors-Inspect" for details.

2. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the injection actuation pressure sensor (P2:61 and P2:62).

3. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

4. Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM.

Expected Result:

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

Results:

• OK - Proceed to Test Step 4.

• Not OK -

  Repair: Perform the following repair:Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.

  STOP

Test Step 4. Check the Status of the Sensor with the Engine OFF

1. Connect Cat ET to the data link connector.

2. Turn the key switch to the ON position.

3. Check the injection actuation pressure on the status screen of Cat ET.

   Note: The following codes will cause the injection actuation pressure sensor to default to 17500 kPa (2538 psi).

   • 164-03 Injection Actuation Pressure Voltage High (15)

   • 164-04 Injection Actuation Pressure Voltage Low (15)

   • 232-03 5 Volt Supply Voltage High (21)

   • 232-04 5 Volt Supply Voltage Low (21)

Expected Result:

The injection actuation pressure sensor indicates 0 kPa (0 psi).

Results:

• Yes - Proceed to Test Step 6.

• No - Proceed to Test Step 5.

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

1. Turn the key switch to the OFF position.

2. Disconnect the electrical connector J204/P204 for the injection actuation pressure sensor from the engine harness.

3. Connect a 3-terminal breakout T to the electrical connector J204 only.

4. Turn the key switch to the ON position.

5. Use a digital multimeter that is set on DC voltage. Measure the voltage supply from terminal A to terminal B at the breakout T.

Expected Result:

The voltage reading should be 4.5 VDC to 5.5 VDC.

Results:

• Yes - Proceed to Test Step 6.

• No -

  Repair: The voltage supply for the injection actuation pressure sensor is not correct. Refer to Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test".

  STOP

Test Step 6. Compare the Reading from the Injection Actuation Pressure Sensor to a Pressure Gauge Reading

Show/hide table

Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

1. Turn the key switch to the OFF position.

2. Install a 8T-0852 Pressure Gauge to an oil supply port on the high pressure oil rail that is located on the cylinder head.

3. Connect Cat ET to the data link connector.

4. Start the engine.

5. Go to the "Injection Actuation Pressure Test" on the Diagnostic Menu of Cat ET.

6. Start the test and monitor the reading from the injection actuation pressure sensor on Cat ET. Compare the pressure reading from Cat ET to the pressure reading on the 8T-0852 Pressure Gauge. Perform a comparison of the two different pressure indicators at varying engine rpm.

   Note: Use Table 1 for the approximate range for the injection actuation pressure sensor. Compare the 8T-0852 Pressure Gauge pressure reading to the pressure reading from the table.

   Show/hide table

   Table 1

   Pressure Reading from Service Tool	Range of the Pressure Gauge Reading
   6000 kPa	4000-7800 kPa (580-1130 psi)
   10000 kPa	8000-11800 kPa (1160-1710 psi)
   15000 kPa	13000-16800 kPa (1885-2435 psi)
   23000 kPa	21000-24800 kPa (3045-3595 psi)

Expected Result:

The reading that is displayed on Cat ET and the reading on the pressure gauge readings agree.

Results:

• Yes -

  Repair: The injection actuation pressure sensor and the ECM are working properly. Refer to Troubleshooting, "Troubleshooting without a Diagnostic Code".

  STOP

• No -

  Repair: Temporarily replace the injection actuation pressure sensor and repeat the test. Replace the injection actuation pressure sensor if this corrects the problem. If the new sensor is out of the acceptable range, then the pressure gauge is faulty.

  STOP