5H41600TZ Mercruiser STERNDRIVE, Bravo-III XR Gas (2.00:1 Ratio) Dual Water Pick-Up

Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
524–3
Desired Engine Speed Sensor : Current Above Normal The Electronic Control Module (ECM) has detected a low amperage for the desired speed signal. The amperage is less than 2 mA for more than 5 seconds. The code is logged.
The alarm output is activated.
524–4
Desired Engine Speed Sensor : Current Below Normal The ECM has detected an excessive amperage in the circuit for the desired speed signal. The amperage has exceeded 22 mA for more than 5 seconds. The code is logged.
The alarm output is activated. Note: For this troubleshooting procedure, the "Desired Speed Input" configuration parameter must be set to "4 - 20 mA Input" in the "Service/Configuration" screen of the Cat Electronic Technician (ET). Do not select "PWM". The ECM cannot be configured to accept a Pulse Width Modulated signal (PWM) for speed control for the engine.The selection of the "4 - 20 mA Input" setting requires a 4 mA to 20 mA signal for regulation of the desired engine speed. Do not use this procedure if the "Desired Speed Input" is set to "0 to 5 VDC Input".When the desired speed input is correspondingly configured, the ECM controls the engine speed according to the 4 mA to 20 mA current.The value of the current corresponds to a range of desired engine speeds between minimum high idle and maximum high idle. The "Minimum Engine High Idle Speed" and the "Maximum Engine High Idle Speed" are set with the "Service/Configuration" screen of Cat ET. For more information, refer to Troubleshooting, "Configuration Parameters".When the idle/rated speed switch is in the RATED position, a current value of 4.0 mA corresponds to the programmed "Minimum Engine High Idle Speed". A current value of 20.0 mA corresponds to "Maximum Engine High Idle Speed". Desired speed input values within this range will vary the desired engine speed in a linear fashion between. The range will vary between "Minimum Engine High Idle Speed" and "Maximum Engine High Idle Speed".The most likely causes of a diagnostic code for this circuit are a poor connection or a problem in a wiring harness. The next likely cause is a problem with a component. The least likely cause is a problem with the ECM.
Illustration 1 g01727394
Schematic of the circuit for the 4 mA to 20 mA desired speed input
Illustration 2 g01697374
Locations of the junction boxes for the speed control circuit (left front engine view)
(1) ECM junction box
(2) Engine junction boxTest Step 1. Inspect the Electrical Connectors and the Wiring
Set the engine control to the OFF/RESET position. Remove the electrical power from the engine.
Illustration 3 g01727513
Location of the connectors at the ECM junction box that are for the speed control circuit
(3) J1/P1 ECM connectors at the ECM
(4) Control harness connectors
Illustration 4 g01727533
Location of the connectors at the engine junction box that are for the speed control circuit
(5) Engine interface connectors
Illustration 5 g01727537
Location of the potentiometer for the speed control at the engine display panel
(6) Speed potentiometer
Thoroughly inspect the condition of connectors (3), (4), and (5). Also, thoroughly inspect the electrical condition and the mechanical condition of speed control (6). Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 6 g01414564
Terminal locations at the P1 ECM connector that are associated with the speed control circuit
(P1-36) Desired speed (4-20 mA)
(P1-37) Return
Illustration 7 g01727553
Terminal locations at the control harness connector that are associated with the speed control circuit
(Terminal C) Desired speed (4-20 mA)
(Terminal P) Return
Illustration 8 g01727540
Terminal locations at the engine interface connectors that are associated with the speed control circuit
(Terminal 10) Desired speed (4-20 mA)
(Terminal 12) Return
Perform a 45 N (10 lb) pull test on each of the wires in the circuit for the speed control.
Check the torque of the allen head screws for each of the ECM connectors and of the customer connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points from the ECM junction box to the remote panel.Expected Result:All connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points.Results:
OK - The components are in good condition with proper connections. Proceed to Test Step 2.
Not OK - The components are not in good condition and/or at least one connection is improper.Repair: Perform the necessary repairs and/or replace parts, if necessary.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Cat