809080 Mercury LOCKWASHER

Table 1
Diagnostic Trouble Codes    
J1939 Codes    Description    
84-1     Wheel-Based Vehicle Speed : Low - Most Severe (3)    
84-2     Wheel-Based Vehicle Speed : Erratic, Intermittent, or Incorrect    
84-8     Wheel-Based Vehicle Speed : Abnormal Frequency, Pulse Width, or Period    
84-10     Wheel-Based Vehicle Speed : Abnormal Rate of Change    Refer to Troubleshooting, "Vehicle Speed - Calibrate" if the vehicle speed is being calibrated in ppm (pulses per mile) or PPKM (pulses per kilometer).The following background information is related to this procedure:The vehicle speed circuit consists of the vehicle speed source and associated wiring. The vehicle speed source is installed by the vehicle OEM. Usually, a sensor reads movement of the transmission output shaft from the teeth on a chopper wheel. The Engine Control Module (ECM) converts the signal from the vehicle speed source into vehicle speed for the following functions:
Cruise control
Fast idle
Idle speed control
Progressive shift
Speedometer
PTO operation
Vehicle speed limiting
Idle shutdown
Operation of the air inlet heater (if equipped)
Secure idle theft deterrent
Trip data
Maintenance dataTo begin troubleshooting a vehicle speed problem, the following information must be determined:The problem is electrical or the problem is a calibration problem.Electrical problems would be an erratic speed signal or no speed signal. A calibration problem would be a stable ECM speed that is still an inaccurate ECM speed. Another calibration problem would be a stable speedometer speed that is still an inaccurate speedometer speed.If the problem is related to vehicle speed calibration, refer to Troubleshooting, "Vehicle Speed - Calibrate" for calibrating the vehicle speed in PPKM (pulses per kilometer) or ppm (pulses per mile). The ECM speedometer output signal is set to 18,600 PPKM (30,000 ppm) for most configurations. For "GM Truck Manufacturer" configurations, the output of the speedometer is set to 2,485 PPKM (4,000 ppm). The ECM speedometer output signal cannot be changed. All speedometers that are driven by the ECM output (J1/P1 terminal 36 and terminal 37) must match the fixed output of the ECM for proper operation.The type of vehicle speed sensor that is installed on the vehicle must be determined.Both single coil magnetic sensors and dual coil magnetic sensors are commonly used. Some vehicles provide the vehicle speed through the transmission ECM.You must determine if the vehicle speedometer is driven from the ECM.The ECM can drive the speedometer through the connection to ECM connector J1-36 (speedometer positive) and/or J1-37 (speedometer negative). Note: The ECM may also drive the speedometer by a connection to the J1587 ATA Data Link, if the instrument cluster is capable of interpreting the signal.Vehicle Speed Circuit WiringThe vehicle speed signal is routed directly into the ECM at ECM vehicle harness connector J1/P1-32 (vehicle speed in positive) and J1/P1-33 (vehicle speed in negative). Speedometer ConnectionIf the vehicle speedometer is driven by the ECM output, the vehicle speedometer will be connected to the ECM vehicle harness connector J1/P1-36 and/or to J1/P1-37. Some speedometers require only one of the ECM signal lines to operate. Other speedometers may require both of the ECM signal lines to operate.Speedometer Special Test If the vehicle speedometer is driven by ECM output, the speedometer circuit can be checked by using the electronic service tool. The "55 mph VSP/Speedometer Test" will drive the speedometer to approximately 55 mph under the following conditions:
The "55 mph VSP/Speedometer Test" is activated.
The circuit is operating properly.
The speedometer is operating properly.Note: While the test is active, the odometer will increment mileage.Magnetic SensorsA magnetic pickup will have only two wires if the magnetic pickup is a single coil magnetic sensor. Also, a magnetic pickup will have four wires if the magnetic pickup is a dual coil magnetic sensor. The magnetic pickup sensor does not require a power connection or a ground connection. Vehicles with Electronic Vehicle Speed SourcesFor these vehicles, the vehicle speed signal is provided by an electronic source. The signal is received over a single wire that is connected to ECM vehicle harness connector J1/P1-32 (vehicle speed in positive). Do not make any other connection to this line. A speedometer is an example of a connection that should not be made to this line. For this type of signal, the ECM vehicle harness connector J1/P1-33 (vehicle speed in negative) must not be connected to the ECM in order to prevent introducing electrical noise into the circuit.For vehicle speed problems on trucks that are equipped with either of these vehicle speed sources, first inspect the wiring from the electronic source to the engine ECM for open circuits or for short circuits.The ECM can be configured to receive vehicle speed information from an electronic transmission control unit via the J1939 data link. The transmission must be capable of supporting the "J1939 ETC1 Broadcast Message (PGN 61,442 Bytes 2 & 3)". This message provides the speed of the transmission output shaft. This feature requires the hardware for the J1939 data link to be installed in the chassis of the vehicle. This also requires a transmission that is electronically controlled and capable of supporting the necessary J1939 protocol.When the engine is configured for the J1939 option, the circuit for the ECM vehicle speed input (terminals 32 and 33) will be ignored. The ECM uses the "Vehicle Speed Cal (J1939-Trans)" parameter value in order to calculate vehicle speed. The ECM uses the parameter value and the speed of the output shaft that is received over the J1939 data link to calculate the vehicle speed. The "Vehicle Speed Cal (J1939-Trans)" parameter is based on the revolutions per mile of the output shaft. There are several methods that can be used to arrive at this calibration value. Refer to Troubleshooting, "Vehicle Speed - Calibrate" for details.The ECM can be configured to receive vehicle speed information from the Anti-lock Brake System (ABS) via the J1939 data link. The ABS must be capable of supporting the "J1939 High Resolution Wheel Speed Broadcast Message (PGN 65, 134 Byte 5-8)", which provides wheel speed from the two rear wheels. The ABS will broadcast the assumed tire revolutions per mile.Regardless of the source that is