C7 and C9 On-Highway Engines Caterpillar

Sensor Supply - Test

Usage:

C7 C7S

System Operation Description:

Use this procedure to troubleshoot the following diagnostic codes:

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Table 1
Diagnostic Codes
J1939 Code	Description
100-10	Engine Oil Pressure : Abnormal Rate of Change
102-10	Engine Intake Manifold #1 Pressure : Abnormal Rate of Change
3509-3	Sensor Supply Voltage 1 : Voltage Above Normal
3509-4	Sensor Supply Voltage 1 : Voltage Below Normal
3510-3	Sensor Supply Voltage 2 : Voltage Above Normal
3510-4	Sensor Supply Voltage 2 : Voltage Below Normal

Background Information

Refer to Illustration 1 and Illustration 2. There are two sensor supplies inside the ECM. Each sensor supply provides 5 VDC to a different connector on the ECM.

Sensor supply 1 provides operating voltage for the engine sensors via the P2 connector. The engine sensors are divided into four groups. A terminal on the P2 connector provides 5 VDC for each group of sensors.

Sensor supply 2 provides operating voltage for sensors that are provided by the OEM via the P1 connector.

100-10 (J1939) Code - This code indicates that the 5 volt supply is missing from the harness connector for the oil pressure sensor. The engine must be running in order for this code to become active. During normal engine operation, the oil pressure fluctuates slightly. When the 5 volt supply is missing from the oil pressure sensor, the signal from the oil pressure sensor goes to a midrange value. The signal does not fluctuate. If the signal from the oil pressure sensor remains abnormally steady for more than 30 seconds, the Engine Control Module (ECM) activates this code. A snapshot is triggered. While this code is active, the ECM uses a default value for the oil pressure.

102-10 (J1939) Code - This code indicates that the 5 volt supply is missing from the harness connector for the intake manifold pressure sensor. The engine must be running in order for this code to become active. During normal engine operation, the intake manifold pressure fluctuates slightly. When the 5 volt supply is missing from the intake manifold pressure sensor, the signal from the intake manifold pressure sensor goes to a midrange value. The signal does not fluctuate. If the signal from the intake manifold pressure sensor remains abnormally steady for more than 30 seconds, the ECM activates this code. A snapshot is triggered. While this code is active, the ECM sets the value of the intake manifold pressure to 100 kPa (14.5 psi). As a result, engine power is reduced.

3509-3 (J1939) Code - This code indicates that the voltage of the P2 5 volt supply is above normal. During normal engine operation, the 5 volt supply should not exceed 5.16 VDC. If the 5 volt supply exceeds this value for more than one second, a snapshot is triggered.

3509-4 (J1939) Code - This code indicates that the voltage of the P2 5 volt supply is below normal. During normal engine operation, the 5 volt supply should not go below 4.84 VDC. If the 5 volt supply goes below this value for more than one second, a snapshot is triggered.

3510-3 (J1939) Code - This code indicates that the voltage of the P1 5 volt supply is above normal. During normal engine operation, the 5 volt supply should not exceed 5.16 VDC. If the 5 volt supply exceeds this value for more than one second, a snapshot is triggered. Engine power is reduced.

3510-4 (J1939) Code - This code indicates that the voltage of the P1 5 volt supply is below normal. During normal engine operation, the 5 volt supply should not go below 4.84 VDC. If the 5 volt supply goes below this value for more than one second, a snapshot is triggered. Engine power is reduced.

The following components can cause problems with the power supply:

Electrical connector or wiring
Sensor
ECM

The most likely cause of a problem is a problem with an electrical connector or wiring. The least likely cause is a problem with the ECM.

Diagnostics on the Caterpillar Electronic Technician (ET)

Wiggle Test - The wiggle test allows you to monitor the status of the power supply while you wiggle the wiring. This helps to identify faulty electrical connections.

The wiggle test cannot be used to troubleshoot -10 codes. For additional information regarding the wiggle test, refer to the documentation that accompanies your Cat ET software.

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Illustration 1	g02140418
Schematic diagram for sensor supply 1

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Illustration 2	g02139841
Schematic diagram for sensor supply 2

Test Step 1. Identify the Diagnostic Code

Identify the diagnostic code.

Results:

Logged -10 code. - Proceed to Test Step 3.
Logged 3509-3 or 3509-4 code - Proceed to Test Step 2.
Active 3509-3 code - Proceed to Test Step 4.
Active 3509-4 code - Proceed to Test Step 6.
Logged 3510-3 or 3510-4 code - Proceed to Test Step 10.
Active 3510-3 code - Proceed to Test Step 11.
Active 3510-4 code - Proceed to Test Step 14.

Test Step 2. Wiggle the Wiring and Look for Problems

Carefully following this procedure is a good way to identify the root cause of an intermittent problem.

Configure Cat ET for the wiggle test. Start the wiggle test.

Note: Problems with the circuit must exist for at least one second before a diagnostic code for the 5 volt supply becomes active.

Slowly wiggle all of the wiring and the connectors between the P2 connector and each sensor. Pay particular attention to the wiring near each connector. As you wiggle the wiring, observe the wiring and the connectors. Look for these problems:
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation

Expected Result:

A "5 Volt Supply" diagnostic code becomes active when the wiring is wiggled.

Results:

Yes - A "5 Volt Supply" diagnostic code becomes active when the wiring is wiggled.
Repair: Repair the wiring, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP
No - A "5 Volt Supply" diagnostic code does not become active when the wiring is wiggled.
Repair: There may be a problem with the P2 connector. Perform the following procedure:
1. Pull on each power wire at the back of the P2 connector in order to verify that the crimp is OK and that the socket is installed correctly.
1. Disconnect the J2/P2 connectors.
1. Carefully inspect the four P2 sockets that relate to the 5 volt supply. Each socket must be clean and dry. Clean the sockets, if necessary.
1. Insert a pin into each of the four P2 sockets that relate to the 5 volt supply. Verify that the socket grips the pin firmly. Repair any problems.
1. Connect the P2 connector. Verify that a diagnostic code for the 5 volt supply does not become active. Return the engine to service.
STOP

Test Step 3. Wiggle the Wiring and Look for Problems

Note: The wiggle test cannot be used to troubleshoot a -10 code.

Carefully following this procedure is a good way to identify the root cause of an intermittent problem.

Verify that the wire insertion side of the harness connector for the applicable sensor is clean.

Use 7X-1710 Multimeter Probes to connect a voltmeter between terminals 1 and 3 on the harness connector for the applicable sensor.

Slowly wiggle all of the wiring and the connectors between the P2 connector and the applicable sensor. Pay particular attention to the wiring near each connector. As you wiggle the wiring, observe the voltmeter, the wiring, and the connectors. Look for these problems:
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation

Expected Result:

The voltmeter reading fluctuates when the wiring is wiggled at a particular location.

Results:

Yes - The voltmeter reading fluctuates when the wiring is wiggled at a particular location.
Repair: Repair the wiring, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP
No - The voltmeter reading remains steady as the wiring is wiggled.
Repair: There may be a problem inside a connector. Perform the following procedure:
1. Pull on the power wire for the sensor at the back of the P2 connector in order to verify that the crimp is OK and that the socket is installed correctly.
1. Disconnect the P2 connector.
1. Carefully inspect the P2 socket that relates to the 5 volt supply for the applicable sensor. The socket must be clean and dry. Clean the socket, if necessary.
1. Insert a pin into the socket. Verify that the socket grips the pin firmly. Repair any problems.
1. Connect the P2 connector. Verify that the voltmeter indicates approximately 5 VDC.
1. Pull on the power wire at the back of the harness connector for the sensor in order to verify that the crimp is OK and that the socket is installed correctly. Repair any problems.
1. Disconnect the harness connector for the sensor. Insert a pin into socket 1. Verify that the socket grips the pin firmly.
1. Connect the harness connector to the sensor. Verify that the voltmeter indicates approximately 5 VDC.
1. Clear the logged -10 code. Return the engine to service.
STOP

Test Step 4. Isolate the Problem

Use a wire removal tool to remove each of the following terminals from the P2 connector. Wait for five seconds after you remove each terminal. This will allow time for the -3 code to clear.

P2-72
P2-80
P2-81
P2-82

Expected Result:

The -3 code disappears when a particular terminal is removed from the P2 connector.

Results:

Yes - The -3 code disappears when a particular terminal is removed from the P2 connector.
Repair: Perform the following procedure:
1. Inspect the terminal and the P2 connector. Look for moisture and for corrosion. Clean the components, if necessary.
1. Insert the terminal into the P2 connector. Look for the -3 code to return.
  If the -3 code does not return, the problem is resolved. Return the engine to service.
  If the code returns, continue with this procedure. The problem is in the wiring or the sensors that are connected to this terminal. Concentrate your troubleshooting on these components for the remainder of this procedure.
Install all of the terminals into the P2 connector. Proceed to Test Step 5.
No - The -3 code is still active after all four terminals are removed from the P2 connector.
Repair: Perform the following procedure:
1. Disconnect the P2 connector. Inspect the P2 and J2 connectors for moisture and for corrosion. Clean the connectors, if necessary.
1. Connect the P2 connector. Look for the diagnostic code again.
  If the -3 code is still active, continue with this procedure.
  If the -3 code is no longer active, install all four sockets into the P2 connector. Pull on each wire in order to verify that the sockets are installed correctly. Verify that the -3 code is no longer active. Clear the diagnostic codes. Return the engine to service.
1. Install a test ECM. Refer to Troubleshooting, "Test ECM Mode".
1. Verify that the test ECM solves the problem. Install the original ECM and verify that the problem returns. Replace the original ECM.
STOP

Test Step 5. Wiggle the Wiring and Look for Problems

Carefully following this procedure is a good way to identify the root cause of an intermittent problem.

Configure Cat ET for the wiggle test. Start the wiggle test.

Note: The circuit must be okay for at least one second in order for the active code to become inactive.

Slowly wiggle the wiring and the connectors between the P2 connector and each sensor that is connected to the terminal that was identified in the previous Test Step. Pay particular attention to the wiring near each connector. As you wiggle the wiring, observe the wiring and the connectors. Look for these problems:
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation

Expected Result:

The -3 diagnostic code becomes inactive when the wiring is wiggled.

Results:

Yes - The -3 diagnostic code becomes inactive when the wiring is wiggled. Alternatively, there is a problem with the wiring.
Repair: Repair the wiring, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP

Test Step 6. Isolate the Problem

Use a wire removal tool to remove each of the following terminals from the P2 connector. Wait for five seconds after you remove each terminal. This will allow time for the -4 code to clear.

P2-72
P2-80
P2-81
P2-82

Expected Result:

The -4 code disappears when a particular terminal is removed from the P2 connector.

Results:

Yes - The -4 code disappears when a particular terminal is removed from the P2 connector.
Repair: Perform the following procedure:
1. Inspect the terminal and the P2 connector. Look for moisture and for corrosion. Clean the components, if necessary.
1. Insert the terminal into the P2 connector. Look for the -4 code to return.
  If the -4 code does not return, the problem is resolved. Return the engine to service.
  If the code returns, continue with this procedure. The problem is in the wiring or the sensors that are connected to this terminal. Concentrate your troubleshooting on these components for the remainder of this procedure.
Install all of the terminals into the P2 connector. Proceed to Test Step 7.
No - The -4 code is still active after all four terminals are removed from the P2 connector.
Repair: Perform the following procedure:
1. Disconnect the P2 connector. Inspect the P2 and J2 connectors for moisture and for corrosion. Clean the connectors, if necessary.
1. Connect the P2 connector. Look for the diagnostic code again. If the -4 code is still active, proceed to the next Test Step.
  If the -4 code is no longer active, install all four sockets into the P2 connector. Pull on each wire in order to verify that the sockets are installed correctly. Verify that the -4 code is no longer active. Clear the diagnostic codes. Return the engine to service.
STOP

Test Step 7. Wiggle the Wiring and Look for Problems

Carefully following this procedure is a good way to identify the root cause of an intermittent problem.

Configure Cat ET for the wiggle test. Start the wiggle test.

Note: The circuit must be okay for at least one second in order for the active code to become inactive.

Slowly wiggle the wiring and the connectors between the P2 connector and each sensor that is connected to the terminal that was identified in the previous Test Step. Pay particular attention to the wiring near each connector. As you wiggle the wiring, observe the wiring and the connectors. Look for these problems:
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation

Expected Result:

The -4 diagnostic code becomes inactive when the wiring is wiggled.

Results:

Yes - The -4 diagnostic code becomes inactive when the wiring is wiggled.
Repair: Repair the wiring, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP
No - The -4 diagnostic code remains active when the wiring is wiggled. Proceed to Test Step 8.

Test Step 8. Check the Sensors

Disconnect a 5 volt sensor. Wait for five seconds. Look for the -4 code to disappear.

Repeat the previous step for each sensor.

Expected Result:

When a particular sensor is disconnected, the -4 code disappears.

Results:

Yes - When a particular sensor is disconnected, the -4 code disappears.
Repair: Perform the following procedure:
1. Carefully inspect the sensor connector and the harness connector for the sensor. Look for these problems:
  - Moisture on the connectors or the wiring
  - Damage that is caused by excessive heat
  - Damage that is caused by chafing
  - Damaged insulation
  Repair any problems. Replace parts, if necessary. Connect the sensor. Replace the sensor if you connect the sensor and the -4 code returns. Verify that the problem is resolved.
STOP
No - All of the applicable sensors are disconnected. The -4 code is still active. Proceed to Test Step 9.

Test Step 9. Check the P2 Connector

Note: Numerous diagnostic codes will become active when you disconnect the P2 connector. Ignore the additional codes and clear the codes when you are finished.

Disconnect the P2 connector.

Carefully inspect the four P2 sockets that relate to the 5 volt supply. Each socket must be clean and dry. Clean the sockets, if necessary.

Insert a pin into each socket that relates to the 5 volt supply. Verify that each socket grips the pin firmly. Repair any problems.

Look for the active code to disappear while the P2 connector is disconnected.

Expected Result:

The active code disappears while the P2 connector is disconnected.

Results:

Yes - The active code disappears while the P2 connector is disconnected. The harness is causing the active diagnostic code.
Repair: Connect the P2 connector and verify that the code returns.Repair the harness. Replace parts, if necessary. Verify that the problem is resolved.
STOP
No - The code remains active while the P2 connector is disconnected.
Repair: Temporarily install a test ECM. Refer to Troubleshooting, "Test ECM Mode". Verify that the test ECM solves the problem. Replace the original ECM. Verify that the problem is resolved.
STOP

Test Step 10. Wiggle the Wiring and Look for Problems

Carefully following this procedure is a good way to identify the root cause of an intermittent problem.

Configure Cat ET for the wiggle test. Start the wiggle test.

Note: Problems with the circuit must exist for at least one second before a diagnostic code for the 5 volt supply becomes active.

Slowly wiggle all of the wiring and the connectors between the P1 connector and the coolant level sensor. Pay particular attention to the wiring near each connector. As you wiggle the wiring, observe the wiring and the connectors. Look for these problems:
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation

Expected Result:

A "5 Volt Supply" diagnostic code becomes active when the wiring is wiggled.

Results:

Yes - A "5 Volt Supply" diagnostic code becomes active when the wiring is wiggled.
Repair: Repair the wiring, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP
No - A "5 Volt Supply" diagnostic code does not become active when the wiring is wiggled.
Repair: There may be a problem with the P1 connector. Perform the following procedure:
1. Turn the keyswitch to the OFF position.
1. Pull on the power wire at the back of the P1 connector in order to verify that the crimp is OK and that the socket is installed correctly.
1. Disconnect the J1/P1 connectors.
1. Carefully inspect socket P1-2. The socket must be clean and dry. Clean the socket, if necessary.
1. Insert a pin into socket P1-2. Verify that the socket grips the pin firmly. Repair any problems.
1. Connect the P1 connector. Turn the keyswitch to the ON position.
1. Verify that a diagnostic code for the 5 volt supply does not become active. Return the engine to service.
STOP

Test Step 11. Wiggle the Wiring and Look for Problems

Carefully following this procedure is a good way to identify the root cause of an intermittent problem.

Configure Cat ET for the wiggle test. Start the wiggle test.

Note: The circuit must be okay for at least one second in order for the active code to become inactive.

Slowly wiggle the wiring and the connectors between the P1 connector and the coolant level sensor. Pay particular attention to the wiring near each connector. As you wiggle the wiring, observe the wiring and the connectors. Look for these problems:
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation

Expected Result:

The -3 diagnostic code becomes inactive when the wiring is wiggled.

Results:

Yes - The -3 diagnostic code becomes inactive when the wiring is wiggled.
Repair: Repair the wiring, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP
No - The -3 diagnostic code remains active as the wiring is wiggled. Proceed to Test Step 12.

Test Step 12. Isolate the Problem

Use a wire removal tool to remove terminal 2 from the P1 connector. Wait for five seconds after you remove the terminal. This will allow time for the -3 code to clear.

Expected Result:

The -3 code disappears when terminal 2 is removed from the P1 connector.

Results:

Yes - The -3 code disappears when a particular terminal is removed from the P1 connector.
Repair: Perform the following procedure:
1. Inspect the terminal and the P1 connector. Look for moisture and for corrosion. Clean the components, if necessary.
1. Insert the terminal into the P1 connector. Look for the -3 code to return.
  If the -3 code does not return, the problem is resolved. Return the engine to service.
  If the -3 code returns, repair the P1 connector. Verify that the problem is resolved.
STOP
No - The -3 code is still active after the terminal is removed from the P1 connector.
Repair: Temporarily install a test ECM. Refer to Troubleshooting, "Test ECM Mode". Verify that the test ECM solves the problem. Replace the original ECM. Verify that the problem is resolved.
STOP

Test Step 13. Wiggle the Wiring and Look for Problems

Carefully following this procedure is a good way to identify the root cause of an intermittent problem.

Configure Cat ET for the wiggle test. Start the wiggle test.

Note: The circuit must be okay for at least one second in order for a -4 diagnostic code to become inactive.

Slowly wiggle the wiring and the connectors between the P1 connector and the coolant level sensor. Pay particular attention to the wiring near each connector. As you wiggle the wiring, observe the wiring and the connectors. Look for these problems:
- Loose connectors or damaged connectors
- Moisture on the connectors or the wiring
- Damage that is caused by excessive heat
- Damage that is caused by chafing
- Improper routing of wiring
- Damaged insulation

Expected Result:

The -4 diagnostic code becomes inactive when the wiring is wiggled.

Results:

Yes - The -4 diagnostic code becomes inactive when the wiring is wiggled.
Repair: Repair the wiring, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP
No - The -4 diagnostic code remains active when the wiring is wiggled. Proceed to Test Step 14.

Test Step 14. Check the Sensor

Disconnect the coolant level sensor. Wait for five seconds. Look for the -4 code to disappear.

Expected Result:

When the coolant level sensor is disconnected, the -4 code disappears.

Results:

Yes - When the coolant level sensor is disconnected, the -4 code disappears.
Repair: Perform the following procedure:
1. Carefully inspect the sensor connector and the harness connector for the sensor. Look for these problems:
  - Moisture on the connectors or the wiring
  - Damage that is caused by excessive heat
  - Damage that is caused by chafing
  - Damaged insulation
  Repair any problems. Replace parts, if necessary. Connect the sensor. Replace the sensor if you connect the sensor and the -4 code returns. Verify that the problem is resolved.
STOP
No - The sensor is disconnected. The -4 code is still active. Proceed to Test Step 15.

Test Step 15. Check the P1 Connector

Remove terminal 2 from the P1 connector.

Carefully inspect terminal P1-2. The socket must be clean and dry. Clean the socket, if necessary.

Insert a pin into the socket. Verify that the socket grips the pin firmly. Repair any problems.

Look for the active code to disappear while terminal 2 is removed from the P1 connector.

Expected Result:

The active code disappears while terminal 2 is removed from the P1 connector.

Results:

Yes - The active code disappears while the terminal is removed. The harness is causing the active diagnostic code.
Repair: Install the socket into the connector and verify that the code returns.Repair the harness. Replace parts, if necessary. Verify that the problem is resolved.
STOP
No - The code remains active while the terminal is removed from the connector.
Repair: Temporarily install a test ECM. Refer to Troubleshooting, "Test ECM Mode". Verify that the test ECM solves the problem. Replace the original ECM. Verify that the problem is resolved.
STOP