Refer to Illustrations 1 and 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.
The most likely cause of a code for a sensor supply is a problem with an electrical connector or wiring.
Use this procedure to troubleshoot the following codes:
| Diagnostic Trouble Codes for Sensor Supply | ||
|---|---|---|
| J1939 Code | Description | Notes |
| 100-10 | Engine Oil Pressure : Abnormal Rate of Change | This code indicates that the output from the oil pressure sensor has been abnormally steady for more than 30 seconds. Usually, this condition occurs because the sensor is not receiving any supply voltage. During normal engine operation, the signal from the oil pressure sensor continuously fluctuates by a very small amount. When the 5 volt supply is missing from the sensor, the sensor's signal goes to a midrange value. The signal does not fluctuate. If the sensor's signal remains abnormally steady for more than 30 seconds, the Engine Control Module (ECM) activates this code. A snapshot is triggered. The ECM uses a default value for the output from the sensor. The engine must be running and the 5 volt supply must be OK in order for this code to become active. The most likely cause of this code is an open in the supply circuit for the sensor. |
| 102-10 | Engine Intake Manifold #1 Pressure : Abnormal Rate of Change | This code indicates that the output from the intake manifold pressure sensor has been abnormally steady for more than 30 seconds. Usually, this condition occurs because the sensor is not receiving any supply voltage. During normal engine operation, the signal from the intake manifold pressure sensor continuously fluctuates by a very small amount. When the 5 volt supply is missing from the sensor, the sensor's signal goes to a midrange value. The signal does not fluctuate. If the sensor's signal remains abnormally steady for more than 30 seconds, the ECM activates this code. A snapshot is triggered. The ECM sets the value of the intake manifold pressure to The engine must be running and the 5 volt supply must be OK in order for this code to become active. The most likely cause of this code is an open in the supply circuit for the sensor. |
| 3509-3 | Sensor Supply Voltage 1 : Voltage Above Normal | This code indicates that the voltage of sensor supply 1 is above normal. During normal engine operation, the supply voltage should not exceed 5.16 VDC. If the supply voltage exceeds this value for more than one second, a snapshot is triggered. Engine power is reduced. The code is activated. |
| 3509-4 | Sensor Supply Voltage 1 : Voltage Below Normal | This code indicates that the voltage of the 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 code is activated. |
| 3510-3 | Sensor Supply Voltage 2 : Voltage Above Normal | This code indicates that the voltage of sensor supply 2 is above normal. During normal engine operation, the supply voltage should not exceed 5.16 VDC. If the supply voltage exceeds this value for more than one second, a snapshot is triggered. Engine power is reduced. The code is activated. |
| 3510-4 | Sensor Supply Voltage 2 : Voltage Below Normal | This code indicates that the voltage of the 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 code is activated. |
| Follow the troubleshooting procedure in order to determine the root cause of these codes. | ||
| |
| Illustration 1 | g01953480 |
|
Schematic diagram for sensor supply 1 | |
| |
| Illustration 2 | g01324921 |
|
Schematic diagram for sensor supply 2 | |
Test Step 1. Identify the Diagnostic Code
- Establish communication between Cat ET and the ECM. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
- Identify the diagnostic code.
Results:
- Logged -3 code or -4 code - Proceed to Test Step 2.
- Logged -10 code. -
Repair: Repair the open circuit between the P2 connector and the appropriate sensor connector. Verify that the problem is resolved.
STOP
- Active 3509-3 code or 3509-4 code - There is a problem that relates to sensor supply 1. Proceed to Test Step 3.
- Active 3510-3 code or 3510-4 code - There is a problem that relates to sensor supply 2. Proceed to Test Step 5.
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.
- Verify that the engine is OFF and that the keyswitch is ON.
- Configure Cat ET to display the active diagnostic codes.
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 the wiring and the connectors between the appropriate ECM connector and each sensor. Pay particular attention to the wiring near each connector. Be sure to wiggle all of the wiring between the ECM connector and each sensor.
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
As you wiggle the wiring, monitor the active diagnostic screen on Cat ET. Look for the code to become active.
Expected Result:
A "5 Volt Supply" diagnostic code became active when the wiring was wiggled.
Results:
- Yes - A "5 Volt Supply" diagnostic code became active when the wiring was 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 did not become active when the wiring was wiggled.
Repair: There may be a problem inside a connector. Perform the following procedure:
- Disconnect the connectors for the sensors that relate to the diagnostic code. Carefully inspect the terminals in each connector for proper installation. Each terminal must be clean and dry. Clean the terminals, if necessary. Pull on each wire at the harness connector in order to verify that the crimp is OK and that the terminal is installed correctly. Repair any problems.
- Insert a pin into each socket. Verify that each socket grips the pin firmly. Repair any problems.
Note: Numerous diagnostic codes will become active when you disconnect the J2/P2 connectors. Ignore the additional codes and clear the codes when you are finished.
- Disconnect the appropriate ECM connector.
- Carefully inspect the sockets that relate to the 5 volt supply. Each socket must be clean and dry. Clean the sockets, if necessary.
- Pull on each wire at the harness connector in order to verify that the crimp is OK and that the terminal is installed correctly. Insert a pin into each socket. Verify that the socket grips the pin firmly. Repair any problems.
- Connect all connectors.
- Wiggle the wiring again. Verify that a diagnostic code for the 5 volt supply does not become active. Return the engine to service.
STOP
Test Step 3. Isolate the Problem
Use a wire removal tool to remove each of the following terminals from the P2 connector:
- P2-72 Sensors for the engine and the CGI system
- P2-80 Intake valve actuation pressure sensor
- P2-81 Sensors for the ARD and the exhaust temperature sensors
- P2-82 Sensors for the Diesel Particulate Filter (DPF)
Wait for at least five seconds after you remove each terminal in order for the code to disappear.
Expected Result:
The code disappears when a particular terminal is removed.
Results:
- The code disappears when a particular terminal is removed. - Note the terminal. Proceed to Test Step 4.
Test Step 4. Check the Sensors
- Refer to the appropriate schematic diagram. Identify the sensors that relate to the terminal that was identified in the previous test step.
- Disconnect each sensor. Wait for at least five seconds after you disconnect each sensor in order for the code to disappear.
Expected Result:
The code remains after all of the appropriate sensors are disconnected.
Results:
- Yes - The code remains after all of the appropriate sensors are disconnected. There is a problem with the wiring. There may be a problem with a connector.
Repair: Determine the cause of the wiring problem. Make the necessary repairs.
STOP
- No - The code disappears when a particular sensor is disconnected.
Repair: Connect the sensor and verify that the code returns. Inspect the connectors for the sensor. Repair any problems with the sensor connector. Replace the sensor, if necessary.
STOP
Test Step 5. Isolate the Problem
Disconnect the coolant level sensor. Look for the diagnostic code to disappear.
Expected Result:
The code remains after the coolant level sensor is disconnected.
Results:
- Yes - The code remains after the coolant level sensor is disconnected. There is a problem with the wiring. There may be a problem with a connector.
Repair: Determine the cause of the wiring problem. Make the necessary repairs.
STOP
- No - The code disappears when the coolant level sensor is disconnected.
Repair: Connect the sensor and verify that the code returns. Inspect the connectors for the sensor. Repair any problems with the sensor connector. Replace the sensor, if necessary.
STOP