885165 Mercruiser SENSOR, Temperature and Pressure

Table 1
Diagnostic Trouble Codes
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
639-9 247-9 J1939 Network #1 : Abnormal Update Rate Another controller has incorrectly stopped transmitting a J1939 speed request (TSC1) or another controller has incorrectly started transmitting a J1939 speed request.
The ECM will log the diagnostic code.
The engine will not start.
1196-2 1639-2 Anti-theft Component Status States : Erratic, Intermittent, or Incorrect The Electronic Control Module (ECM) detects poor communications with the Machine Security System (MSS).
The engine warning lamp will come on and the ECM will log the diagnostic code.
The engine will not start.
1196-9 1639-9 Anti-theft Component Status States : Special Instruction The Electronic Control Module (ECM) detects a loss of communications with the Machine Security System (MSS).
The warning lamp will come on and the ECM will log the diagnostic code.
The engine will not start.
- 246-9 Proprietary CAN Data Link abnormal update rate The proprietary CAN data link cannot communicate correctly.
- 296-9 Transmission Control abnormal update rate The transmission control ECM cannot communicate correctly over the CAN data link with the engine ECM.
- 588-9 Monitor System Display abnormal update rate The engine ECM cannot communicate correctly over the CAN data link with the cab display panel.
- 1603-9 Machine Control Module abnormal update rate The machine control ECM cannot communicate correctly with the engine ECM over the CAN data link.
Follow the troubleshooting procedure to identify the root cause of the fault. Note: Refer to Troubleshooting, "Sensors and Electrical Connectors"for the locations of the components listed in this procedure.The following background information is related to this procedure:The CAN data link is also known as the J1939 data links. A data link is an industry standard for sending data between different devices in the same application.High speed data is transferred via the data link. The data link cannot be accurately tested without complicated equipment. The data link requires a resistance of 60 Ohms between the two wires to transmit the data correctly. This resistance is made up of two 120 Ohm resistors. The two resistors are known as "Terminating Resistors". The terminating resistors should be at opposite ends of a data link circuit. If this resistance is not present, then the data will be intermittent or unreadable.Note: The wiring for a J1939 data link is a shielded twisted pair cable. If the wiring is damaged, the replacement type must be shielded twisted pair cable.
Illustration 1 g03393003
Typical example of the schematic for the CAN data link
Illustration 2 g03393012
View of the pin locations for the CAN data link on the P1 connector
(20) CAN data link positive
(21) CAN data link negative
(22) CAN Shield
Illustration 3 g03393018
View of the pin locations for the CAN data link on the P2 connector
(22) CAN Shield
(23) CAN data link negative
(24) CAN data link positive
Table 2
Troubleshooting Test Steps Values Results
1. Use the "System Communication Status to Check the Status of the Other Devices on the Suspect CAN Data Link"
A. In the electronic service tool, click on the "Diagnostics" tab on the tool bar.
B. Select the "System Communication Status" option from the drop-down list.
Component Identified
Result: One or more of the devices on the suspect data link is not visible on the electronic service tool.
Repair: Thoroughly inspect the electrical connectors for the suspect devices
Refer to Troubleshooting, "Electrical Connectors - Inspect".
Check the power supply to the suspect devices.
If necessary, refer to Troubleshooting, "Electrical Power Supply - Test".
If the fault has been resolved, return the engine to service.
If the fault is still present, proceed to Test Step 2.
Result: All devices are visible on the electronic service tool.
Proceed to Test Step 2.
2. Check the Data Link Terminating Resistance
A. Disconnect the P1 connector from the ECM.
B. Measure the resistance between P1:20 and P1:21.
Between 50 Ohms and 70 Ohms
Result: The resistance is less than 50 Ohms - there is a short circuit in the harness.
Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all the seals are correctly in place and ensure that the connectors are correctly connected.
Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
Result: The resistance is between 110 and 130 Ohms - one of the terminating resistors may have failed.
Repair: Locate the two terminating resistors and remove the two terminating resistors from the harness. Depending on the application, one or both of the terminating resistors may be located in other ECMs on the data link.
Measure the resistance of the two terminating resistors.
If one of the terminating resistors is incorrect, replace the faulty terminating resistor.
If the two terminating resistors are between 110 and 130 Ohms, proceed to Test Step 4.
Result: The resistance is greater than 150 Ohms.
Proceed to Test Step 3.
Result: The resistance is between 50 and 70 Ohms
The resistance is correct. The fault may be in the connection to other devices on the data link.
Proceed to Test Step 3.
3. Check the Data Link Wiring
A. Disconnect each of the connectors that connect other devices on the data link.
B. Use a multimeter to measure the resistance between P1:20 and each of the CAN+ pins on other devices on the CAN data link.
C. Use a multimeter to measure the resistance between P1:20 and pin (G) on the diagnostic connector.
D. Use a multimeter to measure the resistance between P1:21 and each of the CAN- pins on other devices on the CAN data link.
E. Use a multimeter to measure the resistance between P1:21 and pin (F) on the diagnostic connector.
Less than