3126B Engine for Caterpillar Built Machines Caterpillar

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

Use this procedure to troubleshoot the 164-02 Injector Actuation Pressure signal erratic that is active.

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

The injection actuation pressure sensor detects the pressure of the oil in the high pressure oil manifold. The signal from the injection actuation pressure sensor is supplied to the Electronic Control Module (ECM). The ECM uses the signal from the injection actuation pressure sensor to calculate the control signal for the injection actuation pressure control valve.

Illustration 1	g01182972

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 Troubleshooting, "Electronic Service Tool".

2. Turn the keyswitch to the ON position.

   Note:

3. Observe the "Active Diagnostic" screen on Cat ET. Wait at least 15 seconds so that any codes may become active. Look for an active 164-02 diagnostic code.

   Note: If a 164-03 Injector Actuation Pressure voltage high or a 164-04 Injector Actuation Pressure voltage low is active, refer to Troubleshooting, "Engine Pressure Sensor Open or Short Circuit - Test".

Expected Result:

The 164-02 diagnostic code is active.

Results:

• Active code - The 164-02 diagnostic code is active. Proceed to Test Step 3.

• No active code - The 164-02 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 Troubleshooting, "Electrical Inspectors - Inspect".

  STOP

• Not OK - The engine does not start.

  Repair: Refer to Troubleshooting, "Engine Cranks but Will Not Start".

  STOP

Test Step 3. Inspect the Electrical Connectors and the Wiring

1. Turn the keyswitch to the OFF position.

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Illustration 2	g01182300
Left side engine view (typical component locations) (1) Injection Actuation Pressure Control Valve (IAPCV) (2) Injection actuation pressure sensor (3) J2/P2 ECM connector (4) Pressure port for high pressure oil supply (5) Low pressure oil line

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Illustration 3	g01161363
Left side engine view (typical example) (1) J500/P500 Injection actuation pressure control valve connector (2) Injection actuation pressure sensor (3) J2/P2 ECM connector

Note: There are two possible locations for the injection actuation pressure sensor. Refer to Illustrations 2and 3.

2. Thoroughly inspect the connectors for sensors (1) and (2). Also, thoroughly inspect connectors (3). Refer to Troubleshooting, "Electrical Connectors - Inspect".

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Illustration 4	g01183027
P2 terminals that are associated with the injection actuation pressure sensor (P2-2) +5 VDC (P2-3) Return (P2-27) Injection actuation pressure sensor

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Illustration 5	g01159881
Connectors for the injection actuation pressure sensor (A) +5 V 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 Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

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. Turn the keyswitch to the ON position.

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

   Note: If a 164-03 code is active or a 164-04 code is active, the status for the injection actuation pressure will default to 17500 kPa (2538 psi).

Expected Result:

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

Results:

• OK - The status for the injection actuation pressure is 0 kPa (0 psi). Proceed to Test Step 6.

• Not OK - The status for 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. Turn the keyswitch to the OFF position.

2. Disconnect the injection actuation pressure sensor at the harness connector.

3. Turn the keyswitch to the ON position.

4. Measure the voltage between terminals A and B on the harness side of the connectors for the injection actuation pressure sensor.

Expected Result:

The voltage reading is 5.0 ± 0.2 VDC.

Results:

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

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

  Repair: Refer to 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. Turn the keyswitch to the OFF position.

2. Install a 8T-0852 Pressure Gauge in one of the unused oil ports in the high pressure oil rail on the left side of the cylinder head.

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

   Pressure Reading from Service Tool	Range of Readings from 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 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