77065 Mercury SCREW, STARTER MOTOR COVER (2")

Table 1
Diagnostic Codes Table
Code Code Description Conditions Present Response
102-3 Boost Pressure Sensor: Voltage Above Normal (turbocharged versions only) Open circuit or +B short circuit of sensor/harness. Failure of sensor.
Battery voltage is normal. Sensor supply voltage VCC# is normal.
Voltage of boost pressure is 4.9V or above for 3 seconds or more.
System defaults to 65 kPa (9.43 psi).
Warning Level 2
102-4 Boost Pressure Sensor: Voltage Below Normal (turbocharged versions only) Ground short circuit of sensor/harness. Failure of sensor.
Battery voltage is normal. Sensor supply voltage VCC# is normal.
Voltage of boost pressure sensor is 0.2V or below for 3 seconds or more.
System defaults to 65 kPa (9.43 psi).
Warning Level 2
108-3 Barometric Pressure Sensor Error (High Side) Sensor/ECU internal circuit short to +B
Battery voltage is normal
Barometric pressure sensor voltage is 4.850V or more for 3 seconds or more.
Warning Level 2
System defaults to 65 kPa (9.43 psi).
108-4 Barometric Pressure Sensor Error (Low Side) Sensor/ECU internal circuit short to ground.
Battery voltage is normal
Barometric pressure sensor voltage is 0.2V or less for 3 seconds or more.
Warning Level 2
System defaults to 65 kPa (9.43 psi).
132-3 MAF Sensor: Voltage Above Normal Battery voltage is normal
Engine speed is between 800 rpm and 3000 rpm
Target intake mass air flow is 350 or less and it continues for 3 seconds.
Sensor supply voltage is normal.
Mass air flow sensor voltage is 4.9V or more at normal operation for 3 seconds of more. Sensor output is 0.7 times of target value at normal condition.
Engine derates 25%
EGR stops
Intake throttle fully open
Warning Level 3
132-4 MAF Sensor: Voltage Below Normal Battery voltage is normal.
Starter switch signal is not activated.
Sensor supply voltage is normal.
Mass air flow sensor voltage is 0.1 V or less. for 3 seconds or more.
157-3 Rail Pressure Sensor: Voltage Above Normal Battery voltage is normal.
Sensor supply voltage
Voltage of rail pressure sensor is 3.235 V or above. Engine derates 50%
Accelerator limitation: 50%
EGR stops
Intake throttle fully open
Engine forcibly stopped 60 seconds later
157-4 Rail Pressure Sensor: Voltage Below Normal Battery voltage is normal.
Sensor supply voltage is normal.
Voltage of rail pressure sensor is 0.065 V or less.
3251-3 Differential Pressure Sensor: Voltage Above Normal Battery voltage is normal.
Sensor supply voltage is normal.
Starter switch signal is not activated DPF differential pressure sensor voltage is 4.8 V or more for 3 seconds or more. 0 kPa is default value.
Engine derates 25%
Warning Level 2
3251-4 Differential Pressure Sensor: Voltage Below Normal Battery voltage is normal.
Sensor supply voltage is normal.
Starter switch signal is not activated
DPF differential pressure sensor voltage is 0.2 V or less for 3 seconds or more. Note: The -3 codes are open circuit or +B short circuit. The -4 codes are a ground short circuit . These are almost always a harness issue.
Illustration 1 g06111331
Mass air flow sensor
Illustration 2 g06111333
Differential pressure sensor
Illustration 3 g06111336
Rail pressure sensor
Illustration 4 g06111340
Boost pressure sensor
Table 2
Pressure and Voltage Specifications
Engine State DPF Differential Pressure Signal Intake Air Pressure Sensor
Pressure Boost Pressure Sensor Rail Pressure Sensor
Key Switch On Approx .7 V Approx 100 kPa (14.5 psi) Approx 1.0 V Approx 1 V
Engine Running NA 100 to 180 kPa (14.5 to 26.1 psi) 1.0 to 2.2V 1.65 to 1.80 V
No Load Max Speed NA NA NA 2.50-2.85 V
Accelerating (from LI to HI) NA NA NA 2.5-3.3 V
Table 3
Troubleshooting Test Steps Values Results
1. Check for Diagnostic Codes
A. Establish communication between Caterpillar Electronic Technician (ET) and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if