5036810 JOHNSON COVER, Cylinder block

Illustration 1 g01273205
Information for the circuits for the round service tool connectors
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Information for the circuits for the OBD II service tool connectorTest Step 1. Inspect Electrical Connectors and WiringNote: Carefully following this procedure is a good way to identify an intermittent problem.
Perform a visual inspection of the wiring between the P1 connector and the service tool connector. Look for these problems:
Harness damage that is caused by chafing
Harness damage that is caused by excessive heat
Inspect the service tool connector:
Look for moisture on the wiring and on the connector.
Illustration 3 g01273259
Harness side of the service tool connectors
Pull on the wires that are associated with the data links. Pulling verifies that the wire is properly attached to the terminal and that the terminal is properly inserted into the connector.
Inspect the P1 connector:
Look for moisture on the wiring and on the connector.
Illustration 4 g01273266
Harness side of the P1 connector
Pull on the wires that are associated with the data links. Pulling verifies that the wire is properly crimped to the terminal and that the terminal is properly inserted into the connector.Expected Result:All connectors, pins, and sockets are coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The wiring and the connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the wiring or with a connector.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 coupled. Verify that the problem is resolved.STOPTest Step 2. Bypass the Wiring for the Data Link
Connect the 167-9225 Harness (SERVICE TOOL ADAPTER) to the J1 connector, to the 207-6845 Adapter Cable As , and to the vehicle battery.
Try to establish communication between Cat ET and the ECM.Expected Result:Cat ET and the ECM communicate.Results:
Yes - Cat ET and the ECM communicate when the bypass harness is installed. However, communication cannot be established via the vehicle wiring.Repair: If either data link is connected to the vehicle dashboard, disconnect the dashboard electrical connector that contains the wiring for the data link. Try to establish communication between Cat ET and the ECM.The problem is in the dashboard if disconnecting the dashboard allows Cat ET and the ECM to communicate. Refer to the original equipment manufacturer for assistance in repairing the problem.The dashboard is OK if the problem remains and the dashboard is disconnected. Proceed to the next Test Step. If either data link is not connected to the vehicle dashboard, proceed to Test Step 3.
No - Communication between Cat ET and the ECM is not established when the bypass harness is installed.Repair: Temporarily connect a test ECM. Refer to Troubleshooting, "Test ECM Mode". Verify that the problem is resolved.Connect the original ECM and verify that the problem returns. Replace the original ECM.STOPTest Step 3. Check the Wiring for the Data Links for a Short Circuit
Turn the keyswitch OFF.
Disconnect both the positive cable and the negative cable from the vehicle battery in order to avoid false readings.
Disconnect the P1 connector.
Measure the resistance between the following terminals:
P1-8 (ATA Data Link +) and P1-63 (-Battery)
P1-9 (ATA Data Link -) and P1-63 (-Battery)
P1-50 (J1939 Data Link +) and P1-63 (-Battery)
P1-34 (J1939 Data Link -) and P1-63 (-Battery)
Measure the resistance between the following terminals:
P1-8 (ATA Data Link +) and P1-52 (+Battery)
P1-9 (ATA Data Link -) and P1-52 (+Battery)
P1-50 (J1939 Data Link +) and P1-52 (+Battery)
P1-34 (J1939 Data Link -) and P1-52 (+Battery)Expected Result:Each measurement indicates an open circuit.Results:
Yes - Each measurement indicates an open circuit. The wiring for the data links does not have a short circuit. Proceed to Test Step 4.
No - At least one measurement is less than five Ohms. The wiring for a data link has a short circuit.Repair: Determine the cause of the short circuit. Repair the problem, when possible. Replace parts, if necessary. Verify that the problem is resolved. STOPTest Step 4. Check the Wiring for the Data Links for an Open Circuit
Connect a jumper wire between terminals P1-8 and P1-9.
At the service tool connector, measure the resistance between the terminals for the ATA data link.
Connect a jumper wire between terminals P1-34 and P1-50.
At the service tool connector, measure the resistance between the terminals for the J1939 data link.Expected Result:One of the resistance measurements is an open circuit.Results:
Yes - One of the resistance measurements is an open circuit.Repair: Remove the jumper wire from the P1 connector. Determine the cause of the open circuit. Repair the problem, when possible. Replace parts, if necessary. Verify that the problem is resolved. STOP
No - All of the resistance measurements indicate a short circuit.Repair: Remove the jumper wire from the P1 connector. Proceed to Test Step 5.Test Step 5. Check the Termination Resistors for the J1939 Data LinkNote: Perform this test step only if you are troubleshooting a problem with the J1939 data link. Otherwise, proceed to the next Test Step.