87125-ZV0-A21 Honda SEE PART DETAILS - PRI; MARK, SPARE CLIP (E) (Honda Code 4646220).

Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
590-9 Engine Control Module : Abnormal Update Rate The Electronic Control Module (ECM) has not received the last ten messages that were expected from the optional display panel over the Cat Data Link. The code is logged.
The alarm output is activated.
The shutdown output is activated.
The engine is shut down. The Cat Data Link is used to provide communication between the following components:
Master ECM
Slave ECM
Advisor Monitor Display
Service tool
Customer installed componentsThe ECM and the Advisor module communicate with Caterpillar Electronic Technician (ET) via the Cat Data Link. The Cat Data Link consists of two wires that are a twisted pair.The most likely cause of a diagnostic code for the Cat Data Link is an open circuit or a short circuit. Connector terminals that are not fully seated in the connector body can create an open circuit condition. Do not interchange the polarity of the wires for the data link in a connector. The Cat Data Link will not operate if the polarity of the wires are interchanged in a connector.Communications over the Cat Data Link will fail if a module is not receiving power. Failed communication can happen if there is a problem with the power supply wiring for the module. Refer to the appropriate circuit test in this manual in order to check for power at the module before troubleshooting the data link.Communications over the Cat Data Link can fail with the following conditions: a module is programmed with the wrong flash file, a module has not been programmed with a flash file. The following modules utilize flash programming to update the module software:
Master ECM
Slave ECM
Advisor Monitor DisplayVerify that all modules have been programmed with the most current flash file.Harness Code for the Slave ECMThe harness inside the terminal box for the slave ECM incorporates a jumper wire that sets the harness code for the slave ECM. The harness code is set by a jumper wire across terminals J3-29 and J3-60. The ECM detects the jumper wire and a unique identification code is used by the ECM to communicate over the data link. This jumper allows the ECM to be identified as the slave ECM while the ECM communicates to other modules over the data link. The harness code is necessary for the different modules to communicate over the Cat Data Link. If the connection for the harness code jumper wire fails, Cat ET will display "Duplicate Type on data link. Unable to Service".
Illustration 1 g03082237
Typical schematic for the Cat Data Link
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the engine control switch to the OFF/RESET position. Remove the electrical power from the engine.
Illustration 2 g01697374
Locations of the junction boxes for the Cat Data Link (left front engine view)
(1) ECM junction box
(2) Engine junction box
Illustration 3 g01732873
Location of the service tool connector at the advisor monitor display
(3) Service tool connector
Illustration 4 g01732874
Location of the connectors at the ECM junction box for the Cat Data Link (left front engine view)
(4) J1/P1 ECM connectors for the ECM
(5) Control harness connectors
(6) Service tool connector
Illustration 5 g01732875
Location of the connectors at the engine junction box that are for the Cat Data Link (left side engine view)
(7) Engine interface connectors for the harness to the ECM
(8) Interconnect harness connectors for the harness to the advisor monitor display
Thoroughly inspect connectors (3 through 8). Inspect the twisted pair wiring that is in the harness between each of the modules. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 6 g01418140
Terminal locations at the P1 ECM connector that are for the Cat Data Link
(P1-8) Cat Data Link +
(P1-9) Cat Data Link −
Illustration 7 g01732876
Terminal locations on the control harness connector at the ECM junction box for the Cat Data Link
(Terminal A) Cat Data Link +
(Terminal B) Cat Data Link −
Illustration 8 g01733115
Terminal locations on the engine interface connector at the ECM junction box for the Cat Data Link
(Terminal 13) Cat Data Link +
(Terminal 14) Cat Data Link −
Illustration 9 g01733116