Use this procedure if the electronic service tool will not communicate with the Electronic Control Module (ECM) through the data link.
The following background information is related to this procedure:
The data link is the standard data link that is used by the ECM in order to communicate with the electronic service tool.
The ECM provides multiple connections for the data link. The technician must ensure that the correct connector is being tested.
The positive signal on the data link is from P2:21 to J23:D. The negative signal on the data link is from P2:20 to J23:E. Refer to Illustration 1.
The following information refers to the pin number. Ensure that the correct connector is used.
Communication
The electronic service tool may indicate the following error message:
The version of the ECM is not recognized and the integrity of the changed parameters and displayed data is not guaranteed.
This message will indicate that the version of the software that is in the electronic service tool is not the same version of the software that is in the ECM. Install the latest version of the software for the electronic service tool in order to rectify the fault.
Illustration 1 | g01589673 |
Schematic of the diagnostic connector and the ECM connector |
Illustration 2 | g01759897 |
Typical view of the P2 pin locations for the data link connectors (20) Data link - (21) Data link + |
Test Step 1. Inspect Electrical Connectors and Wiring
- Thoroughly inspect the following electrical connectors:
- P2/J2 ECM connector
- Pin D for the diagnostic connector
- Pin E for the diagnostic connector
- Connectors for the electronic service tool
Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
- P2/J2 ECM connector
- Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the data link.
- Check the screw for the ECM connectors for correct torque of 5.0 N·m (44 lb in).
- Check the harness for abrasion and pinch points from the wires that connect the diagnostic connector to the ECM.
Expected Result:
All connectors, pins and sockets should be completely coupled and/or inserted. The harness should be free of corrosion, abrasion and/or pinch points.
Results:
- OK - Proceed to Test Step 2.
- Not OK -
Repair: Perform the following repair:Repair the connectors and/or the harness, or replace the connectors and/or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are completely coupled.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
STOP
Test Step 2. Determine the Type of Fault in the Data Link
- Connect the electronic service tool to the diagnostic connector that is on the cabinet for the control panel.
- Turn the keyswitch to the ON position.
Expected Result:
The power lamp should illuminate on the communications adapter.
Results:
- OK - The communications adapter is currently receiving the correct voltage.
Repair: If you are redirected to this step from "Check the wiring of the Diagnostic Connector"and if a jumper wire has been installed between pin "A" on the diagnostic connector and the positive terminal on the battery and if a jumper wire has been installed between pin "B" on the diagnostic connector and the negative terminal on the battery, remove the jumper wires and then repair the harness. If the harness cannot be repaired, replace the harness.
Proceed to Test Step 5.
- Not OK - The communications adapter is not receiving the correct voltage. Proceed to Test Step 3.
Test Step 3. Check the Wiring of the Diagnostic Connector
Illustration 3 | g01241517 |
Typical view of the diagnostic connector from the wire side (A) Switched battery + (B) Battery ground (GND) (D) Data link + (E) Data link - |
- If the communications adapter is connected to the diagnostic connector on the cabinet for the control panel, ensure that pin "A" and pin "B" are connected to the power connections in the control panel.
Expected Result:
The pins are wired.
Results:
- OK - The harness is fully wired. Proceed to Test Step 4.
- Not OK - The power connections for the diagnostic connector are not wired.
Repair: Fabricate a jumper wire in order to connect pin "A" of the diagnostic connector to the battery+ bus and pin "B" to the battery - bus.
Proceed to Test Step 2.
Test Step 4. Check the Battery Voltage at the Diagnostic Connector
- Turn the keyswitch to the ON position.
- Use a multimeter in order to measure the voltage from pin A (+battery) and pin B (ground) of the diagnostic connector.
Expected Result:
The voltage is between 11.0 Volts DC and 13.5 Volts DC for a 12 Volt system or the voltage is between 22.0 Volts DC and 27.0 Volts DC for a 24 Volt system.
Results:
- OK - The diagnostic connector is currently receiving the correct voltage. Proceed to Test Step 5.
- Not OK - The diagnostic connector is not receiving the correct voltage.
Repair: Refer to Troubleshooting, "Engine Wiring Information"..
Proceed to Test Step 2.
Test Step 5. Check the Data Link Connections
- Turn the keyswitch to the OFF position.
- Disconnect the communications adapter from the diagnostic connector.
- Disconnect P2 from connector J2. Check the resistance between P2:21 and diagnostic pin "D".
- Check the resistance between P2:20 and diagnostic pin "E".
Expected Result:
The resistance that is measured is less than 10 Ohms.
Results:
- OK - The resistance is less than 10 Ohms. Proceed to Test Step 6.
- Not OK - The resistance is greater than 10 Ohms.
Repair: Perform the following repair:Repair the connectors and/or the harness, or replace the connectors and/or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are completely coupled.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
STOP
Test Step 6. Change the Electronic Service Tool Components
- If another electronic engine is available, connect the electronic service tool to the other engine. Ensure that the same cables are used.
- Turn the keyswitch to the ON position. Determine if the electronic service tool operates correctly on the other engine.
- If another engine is not available, obtain a replacement communications adapter and a replacement set of cables. Ensure that the set of cables for the electronic service tool are a complete set.
- Install the replacement communications adapter and the set of cables for the electronic service tool and connect to the diagnostic connector.
- Turn the keyswitch to the ON position.
- If changing the communications adapter or the cables allows the electronic service tool to operate correctly, use the following procedure:
- Replace the components from the new set of cables with components from the oldset of cables. Replace one component at a time.
- Apply power to the electronic service tool after each of the components is replaced. Use this method to find the faulty component.
- If changing the cables does not allow the electronic service tool to operate correctly, connect another electronic service tool.
- Turn the keyswitch to the ON position.
Expected Result:
Result 1 The original electronic service tool works on another engine.
Result 2 A different electronic service tool works on the original engine while the engine is being tested.
Results:
- Result 1 - Proceed to Test Step 7.
- Result 2 -
Repair: Send the faulty electronic service tool for repairs.
STOP
Test Step 7. Connect an Electronic Service Tool and the ECM to another Battery
- Connect the battery wires from the bypass harness of the electronic service tool to a different battery that is not on the engine.
Batteries give off flammable fumes which can explode. To avoid injury or death, do not strike a match, cause a spark, or smoke in the vicinity of a battery. |
NOTICE |
---|
Do not connect the bypass harness to the battery until the in-line fuse has been removed from the Battery+ line. If the fuse is not removed before connection to the battery, a spark may result. |
Note: Refer to Troubleshooting, "Electronic Service Tools" for details of the bypass harness.
Illustration 4 | g01589844 |
Schematic of the bypass harness connector |
Illustration 5 | g01589898 |
Typical view of the pin locations on connector P1 for the power connections (1) Battery ground (GND) (2) Battery ground (GND) (3) Battery ground (GND) (7) Battery + (8) Battery + (9) Battery ground (GND) (10) Battery ground (GND) (15) Battery + (16) Battery + (40) Keyswitch |
Illustration 6 | g01589924 |
Typical view of the pin locations on connector P2 for the diagnostic and data link connectors (20) Data link - (21) Data link + (22) J1939 (CAN) shield (23) J1939 (CAN) - (24) J1939 (CAN) + |
Expected Result:
The electronic service tool is operating correctly.
Results:
- OK -
Repair: Refer to Troubleshooting, "Engine Wiring Information".
STOP
- Not OK -
Repair: Perform the following repair:
- Make sure that the latest flash file for the application is installed in the ECM. Refer to Troubleshooting, "Flash Programming".
- Use the electronic service tool to check for active diagnostic codes.
- If a diagnostic code is still active, contact the Technical Communicator at a Caterpillar dealer.
Note: This consultation can greatly reduce the repair time.
- If the Technical Communicator recommends the use of a test ECM, install a test ECM. Refer to Troubleshooting, "Replacing the ECM".
- Use the electronic service tool to verify that the fault is eliminated.
- If the fault is eliminated with the test ECM, reconnect the suspect ECM. Verify that the active diagnostic code returns.
- If the active diagnostic code returns with the suspect ECM, replace the ECM.
- Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repairs have eliminated the fault.
STOP