5036677 JOHNSON DECAL, "BOMBARDIER"

Illustration 1 g01065665
Duty cycles that are low, medium, and high
The Electronic Control Module (ECM) supplies 8.0 0.8 VDC to each PWM sensor.Note: Excessive pressure can generate false "noisy signal" diagnostic codes.If the actual air inlet pressure is greater than approximately 338 kPa (49 psi), a diagnostic code will be generated. Although there is not a problem with the sensor, the code will be generated.If the actual engine coolant pressure is greater than approximately 444 kPa (64 psi), a 109-8 Engine Coolant Outlet Pressure Sensor noisy signal diagnostic code will be generated. Although there is not a problem with the sensor, the code will be generated.If a diagnostic code is generated, measure the absolute pressure with a pressure gauge before you troubleshoot the sensor. If the pressure is actually too high, reduce the pressure in order to avoid activation of false diagnostic codes.Logged diagnostic codes provide a historical record. Before you begin this procedure, print the logged codes to a file.This troubleshooting procedure may generate additional diagnostic codes. Keep your mind on correcting the cause of the original diagnostic code. Clear the diagnostic codes after the problem is resolved.
Illustration 2 g01325372
Schematic for the PWM sensors
Test Step 1. Inspect the Electrical Connectors and Wiring
Remove the electrical power from the engine. Note: For the following steps, refer to Troubleshooting, "Electrical Connectors - Inspect".
Thoroughly inspect the following connectors:
J1/P1 connectors
J2/P2 connectors
J7/P7 connectors
The connectors for each PWM sensor
Check the torque of the allen head screw for the ECM connectors.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the PWM sensors.
Check the harness and wiring for abrasion and for pinch points from each of the PWM sensors to the ECM. Expected Result:The 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 "8 Volt DC Supply" Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Switch the 35 amp circuit breaker ON. Set the engine control to the STOP mode.
Observe the "Active Diagnostic" screen on Cat ET. Allow a minimum of thirty seconds for any codes to activate. Look for these codes:
41-3 8 Volt DC Supply : Voltage Above Normal
41-4 8 Volt DC Supply : Voltage Below NormalExpected Result:There are no active diagnostic codes for the 8 volt supply.Results:
No codes - There are no active diagnostic codes for the 8 volt supply. Proceed to Test Step 3.
Active code - There is an active diagnostic code for the 8 volt supply. This procedure will not work when this type of code is active.Repair: Refer to Troubleshooting, "Sensor Supply - Test".STOPTest Step 3. Check for Active Diagnostic Codes for the PWM Sensors
Turn on the "Active Diagnostic" screen on Cat ET. Determine if any of these diagnostic codes are active:
106-3 Air Inlet Pressure Sensor : Voltage Above Normal
106-4 Air Inlet Pressure Sensor : Voltage Below Normal
109-3 Engine Coolant Outlet Pressure Sensor : Voltage Above Normal
109-8 Engine Coolant Outlet Pressure Sensor : Abnormal Frequency, Pulse Width, or PeriodExpected Result:One of the above codes is active.Results:
Yes - At least one of the above diagnostic codes is active. Proceed to Test Step 4.
No - None of the above codes are active.Repair: If any of the above codes are logged and the engine is not running properly, refer to Troubleshooting, "Symptom Troubleshooting".If the engine is running properly at this time, there may be an intermittent problem in the harness that is causing the codes to be logged. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOPTest Step 4. Verify the Supply Voltage to the Sensor
Set the engine control to the OFF/RESET mode.
Disconnect the suspect sensor.
Set the engine control to the STOP mode.
Illustration 3 g00896288
Harness connector for the PWM sensors
(A) 8 volt supply
(B) Return
At the harness connector for the suspect sensor, measure the voltage between terminals (A) and (B). Expected Result:The voltage is between 7.6 VDC and 8.4 VDC.Results:
OK - The voltage is within the specification. The correct voltage is present at the sensor connector. Proceed to Test Step 5.
Not OK - The voltage is not within the specification. The correct voltage is not present at the sensor connector. The correct voltage must be present at the sensor connector in order to continue this procedure.Repair: Verify that the wiring and/or connectors are OK. Repair any faulty wiring and/or connectors, when possible. Replace any faulty wiring and/or connectors, if necessary. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOPTest Step 5. Verify that +Battery Voltage is Not Present in the Signal Wire
Illustration 4 g00896299
Harness connector for the PWM sensors
(B) Return
(C) Signal
At the harness connector for the suspect sensor, measure the voltage between terminal (B) and terminal (C). Expected Result:The voltage is between 7.0 VDC and 8.0 VDC.Results:
OK - The voltage is between 7.0 VDC and 8.0 VDC. The battery voltage is not present in the signal wire. Proceed to Test Step 6.
Not OK - The voltage is approximately equal to the battery voltage. The signal wire is probably shorted to the battery between the sensor and the ECM.Repair: Repair the harness, when possible. Replace the harness, if necessary.STOP
Not OK - The voltage is approximately 0 volts. The signal wire is probably shorted to ground between the sensor and the ECM.Repair: Repair the harness, when possible. Replace the harness, if necessary.STOP