853705 2 Mercury CAP

Table 1
Diagnostic Codes Table
Code Code Description Conditions Notes
102-3 Boost Pressure Sensor: Voltage Above Normal Battery voltage is normal. Sensor supply voltage is normal. The intake air pressure sensor voltage is 4.9 v or higher for 2.8 seconds or more.
The system will use a default pressure of 101.3 kPa (14.7 psi) while this code is active.
Warning Level 2
102-4 Boost Pressure Sensor: Voltage Below Normal Battery voltage is normal. Sensor supply voltage is normal. The intake air pressure sensor voltage is .2V or lower for 2.8 seconds or more.
The system will use a default pressure of 101.3 kPa (14.7 psi) while this code is active.
Warning Level 2
108-3 Barometric Pressure Sensor: Voltage Above Normal Battery voltage is normal
Barometric pressure sensor voltage is 1.6 V or less for 2.8 seconds or more.
Warning Level 2
System defaults to 65 kPa (9.4 psi).
108-4 Barometric Pressure Sensor: Voltage Below Normal Battery voltage is normal
Barometric pressure sensor voltage is 4.4 V or more for 2.8 seconds or more.
Warning Level 2
System defaults to 65 kPa (9.4 psi).
132-3 MAF Sensor: Voltage Is Above Normal
Mass air flow sensor voltage is 4.9 V for 2.8 seconds or more
MAF sensor output defaults to .7 times of target value at normal condition
EGR stop
Intake throttle 100% open
Engine Derate
Warning Level 3
132-4 MAF Sensor: Voltage Is Below Normal
Mass air flow sensor voltage is .1 volts or less for 2.8 seconds or more.
MAF sensor output defaults to .7 times of target value at normal condition
EGR stop
Intake throttle 100% open
Engine Derate
Warning Level 3
157-2 Common Rail Pressure Sensor Signal Keeping Middle Range (Only applies to C3.8 Tier 4 Interim / Stage IIIB.) Engine Switch is ON
Engine speed is 850 rpm or more.
Target rail pressure is 32 MPa or more and actual rail pressure is 20 MPa or more.
Target Injection Quantity is 25 mm3/st. Average Target Pressure - Average Actual Presure is 5 MPa or more during 160 msec is within 0.01V (conversion to voltage). Must occur 3 times.
Engine derates 50 percent.
Speed limitation (acceleration limited 50%).
EGR stop.
Engine stopped 60 seconds later.
157-3 Rail Pressure Sensor: Voltage Above Normal Battery voltage is normal. Sensor supply voltage is normal
The voltage is 4.9 v or higher. Engine derates to 50 percent. Rail pressure is limited to less than 80 MPa. Engine stops after 60 seconds.
Warning Level 3
157-4 Rail Pressure Sensor: Voltage Below Normal Battery voltage is normal. Sensor supply voltage is normal
The voltage is .7 v or lower.
Engine derates to 50 percent.
Rail pressure is limited to less than 80 MPa.
Engine stops after 60 seconds.
Warning Level 3
3251-3 Differential Pressure Sensor: Voltage Above Normal NA
The voltage is 4.9V or more for more than 2.8 seconds. Engine is derated.
Warning Level 2
3251-4 Differential Pressure Sensor: Voltage Below Normal NA
The voltage is 0.1V or less for more than 2.8 seconds. Engine is derated.
Warning Level 2
523631-2 Invalid Intake MAF Data per Cylinder
Only applies to C3.8 Tier 4 Final / Stage IV Battery voltage is normal
IG switch signal (ECM: V13 & V33, DCU: 18 terminal) is continuously activated more than 2 seconds
Starter switch signal (ECM: V12 terminal) is not activated except within 2 seconds after starter stopped
CAN communication is normal between DCU and engine ECM Stop DEF injection
If intake MAF data per cylinder are invalid, the correct DEF injection cannot be performed due to the NOx gross weight cannot be calculated. Therefore the DEF injection is inhibited. Note: Diagnostic codes for a short circuit or an open circuit are most commonly caused by an engine harness routing issue near a connector. Refer to Special Instruction, REHS7774 for more information on installation of a jumper harness
Illustration 1 g03828662
Only applies to C3.8 Tier 4 Interim / Stage IIIB.
Illustration 2 g06170562
Table 2
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 necessary.
B. Turn the keyswitch to the ON position.
C. Look for a -3, or -4 active or logged codes:
Diagnostic code
Result: A -3 diagnostic code is active.
Proceed to Test Step 2.
Result: A -4 diagnostic code is active.
Proceed to Test Step 3.
Result: A 2458-2 or 3251-2 diagnostic code is active.
Proceed to Test Step 6.
2. Create a Short at the Sensor Connector
A. Use a jumper wire to create a short between the signal and ground terminals of the sensor connector.
B. Turn the keyswitch to the ON position.
C. Monitor the diagnostic codes on Cat ET. Check for an active -4 diagnostic code for the suspect sensor.
D. Turn the keyswitch to the OFF position.
Short created
Result: A -4 diagnostic code became active after creating the short at the sensor connector.
The wiring is OK. Replace the sensor.
Verify that the problem is resolved.
Result: A -4 diagnostic code does not become active for the suspect sensor.
Proceed to Test Step 4.
3. Create an Open at the Suspect Sensor Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the sensor connector of the suspect sensor with the active -4 diagnostic code.
C. Turn the keyswitch to the ON position.
D. Monitor the diagnostic codes on Cat ET. Check for an active -3 diagnostic code for the suspect sensor.
E. Turn the keyswitch to the OFF position.
Create a