856178T 3 Mercury ECM

Table 1
Diagnostic Codes Table    
J1939 Code and Description     Conditions which Generate this Code     System Response    
91-8 Throttle Position Sensor abnormal frequency, pulse width, or period     The Electronic Control Module (ECM) detects an abnormal throttle signal for five seconds.     The code is logged.    The direct fuel control mode enables the engine to be controlled by an external governor. A signal converter must be installed on the engine in order to operate in direct fuel control mode. Ensure that the "Direct Fuel Control Mode" configuration parameter is programmed to "Enabled". The ECM will then be configured for a control strategy that supports the direct fuel control mode.The input to the signal converter must be a 0 to 200 mA signal. The signal is received from the external governor. The output signal from the signal converter is a Pulse Width Modulated signal (PWM) that is sent to the ECM.The output signal varies with the current to the signal converter. The ECM calculates the desired fuel from this PWM signal.The duty cycle for a valid signal is between 5 and 95 percent. If an invalid signal is received, the engine will automatically be set to a minimum fuel setting and the engine will shut down.The following ECM control strategies are not used in direct fuel control mode.
Low idle speed
Crank terminate speed
Cooldown speed
Illustration 1 g02212773
Typical exampleSchematic for the direct fuel control mode
Illustration 2 g02217154
Terminal locations at the P1 ECM connector (P1-5) Return (P1-66) Throttle signalTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the Engine Control Switch (ECS) to the OFF position. Turn the battery disconnect