Diagnostic Code List
Use the instrument cluster or use the Caterpillar Electronic Technician (Cat ET) to determine the diagnostic codes for the Transmission ECU. After determining the diagnostic codes, refer to the corresponding test procedure for more information. Perform the procedure that corresponds with the correct diagnostic code. The following table is a list of possible diagnostic codes for the ECU.
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| Diagnostic Trouble Codes For Transmission ECM (MID 81) | ||
|---|---|---|
| DTC | Description | Test Procedure |
| 120-1 | Torque Conv Oil Temp Sensor Data Valid But Below Normal Operational Range | Sensor Signal (Analog, Passive) - Test |
| 120-3 | Torque Conv Oil Temp Sensor Voltage Above Normal | Sensor Signal (Analog, Passive) - Test |
| 120-4 | Torque Conv Oil Temp Voltage Below Normal | Sensor Signal (Analog, Passive) - Test |
| 124-1 | Transmission Oil Level – Data Valid But Below Normal Operational Range | Sensor Signal (Analog, Passive) - Test |
| 124-3 | Transmission Oil Level - Voltage Above Normal | Sensor Signal (Analog, Passive) - Test |
| 124-4 | Transmission Oil Level - Voltage Below Normal | Sensor Signal (Analog, Passive) - Test |
| 126-16 | Transmission Oil Filter Plugged | |
| 127-3 | Transmission Oil Pressure: Voltage Above Normal | Sensor Signal (PWM) - Test |
| 127-4 | Transmission Oil Pressure: Voltage Below Normal | Sensor Signal (PWM) - Test |
| 161-2 | Torque Conv. Output Speed Sensor Erratic | Speed Sensor - Test |
| 161-8 | Torque Conv. Output Speed Sensor Abnormal PW, Freq, Period | Speed Sensor - Test |
| 168-1 | Electrical System Voltage Low | Electrical Power Supply - Test |
| 177-3 | Trans Oil Temp Sensor Voltage Above Normal | Sensor Signal (Analog, Passive) - Test |
| 177-4 | Trans Oil Temp Sensor Voltage Below Normal | Sensor Signal (Analog, Passive) - Test |
| 190-2 | Engine Speed Sensor Erratic | Speed Sensor - Test |
| 190-4 | Engine Speed Sensor: Voltage Below Normal | Speed Sensor - Test |
| 190-8 | Engine Speed Sensor Abnormal Signal | Speed Sensor - Test |
| 191-2 | Transmission Output Shaft Speed: Erratic, Intermittent, or Incorrect | Speed Sensor - Test |
| 191-4 | Transmission Output Shaft Speed: Voltage Below Normal | Speed Sensor - Test |
| 191-8 | Transmission Output Shaft Speed: Abnormal Frequency, Pulse Width, or Period | Speed Sensor - Test |
| 524-9 | Shifter Selector Abnormal Update Rate | Sensor Signal (PWM) - Test |
| 524-14 | Shifter Selector Erratic | Sensor Signal (PWM) - Test |
| 525-2 | Trans Gear Lever Sel. Sensor Erratic, Intermittent, Incorrect | Sensor Signal (PWM) - Test |
| 525-9 | Transmission Requested Gear: Abnormal Update Rate (Shifter Lost) | Cat Data Link - Test |
| 639-9 | J1939 Network #1: Abnormal Update Rate (No CAN Communication) | Cat Data Link - Test |
| 639-14 | J1939 Network #1: Special Instruction (Engine is not on the CAN Network) | Cat Data Link - Test |
| 678-3 | 8V Sensor Power Supply Voltage Above Normal | Electrical Power Supply - Test |
| 678-4 | 8V Sensor Power Supply Voltage Below Normal | Electrical Power Supply - Test |
| 682-2 | Lockup Disable Switch Incorrect | Switch Circuits - Test |
| 734-3 | Transmission Solenoid Clutch #1 Voltage Above Normal | Solenoid Valve - Test |
| 734-5 | Transmission Solenoid Clutch #1 Current Below Normal | Solenoid Valve - Test |
| 734-6 | Transmission Solenoid Clutch #1 Current Above Normal | Solenoid Valve - Test |
| 734-11 | Transmission Solenoid Clutch #1 Other Failure Mode (Coil Resistance?) | Solenoid Valve - Test |
| 735-3 | Transmission Solenoid Clutch #2 Voltage Above Normal | Solenoid Valve - Test |
| 735-4 | Transmission Solenoid Clutch #2 Current Below Normal | Solenoid Valve - Test |
| 735-5 | Transmission Solenoid Clutch #2 Current Above Normal | Solenoid Valve - Test |
| 735-11 | Transmission Solenoid Clutch #2 Other Failure Mode (Coil Resistance?) | Solenoid Valve - Test |
| 736-3 | Transmission Solenoid Clutch #3 Voltage Above Normal | Solenoid Valve - Test |
| 736-5 | Transmission Solenoid Clutch #3 Current Below Normal | Solenoid Valve - Test |
| 736-6 | Transmission Solenoid Clutch #3 Current Above Normal | Solenoid Valve - Test |
| 736-11 | Transmission Solenoid Clutch #3 Other Failure Mode (Coil Resistance?) | Solenoid Valve - Test |
| 737-3 | Transmission Solenoid Clutch #4 Voltage Above Normal | Solenoid Valve - Test |
| 737-5 | Transmission Solenoid Clutch #4 Current Below Normal | Solenoid Valve - Test |
| 737-6 | Transmission Solenoid Clutch #4 Current Above Normal | Solenoid Valve - Test |
| 737-11 | Transmission Solenoid Clutch #4 Other Failure Mode (Coil Resistance?) | Solenoid Valve - Test |
| 738-3 | Transmission Solenoid Clutch #5 Voltage Above Normal | Solenoid Valve - Test |
| 738-5 | Transmission Solenoid Clutch #5 Current Below Normal | Solenoid Valve - Test |
| 738-6 | Transmission Solenoid Clutch #5 Current Above Normal | Solenoid Valve - Test |
| 738-11 | Transmission Solenoid Clutch #5 Other Failure Mode (Coil Resistance?) | Solenoid Valve - Test |
| 739-3 | Transmission Solenoid Clutch #6 Voltage Above Normal | Solenoid Valve - Test |
| 739-5 | Transmission Solenoid Clutch #6 Current Below Normal | Solenoid Valve - Test |
| 739-6 | Transmission Solenoid Clutch #6 Current Above Normal | Solenoid Valve - Test |
| 739-11 | Transmission Solenoid Clutch #6 Other Failure Mode (Coil Resistance?) | Solenoid Valve - Test |
| 740-3 | Transmission Lockup Clutch Solenoid Voltage Above Normal | Solenoid Valve - Test |
| 740-5 | Transmission Lockup Clutch Solenoid Current Below Normal | Solenoid Valve - Test |
| 740-6 | Transmission Lockup Clutch Solenoid Current Above Normal | Solenoid Valve - Test |
| 740-11 | Transmission Lockup Clutch Solenoid Other Failure Mode (Coil Resistance?) | Solenoid Valve - Test |
| 788-13 | Transmission Clutch Actuator: Out of Calibration (Run Fill Calibration and Engage Calibration) | Solenoid Valve - Test |
| 1675-5 | Starter Motor Relay Current Below Normal | Relay - Test |
| 1675-6 | Starter Motor Relay Current Above Normal | Relay - Test |
| 2908-3 | Starter Motor Relay Current Above Normal | Relay - Test |
| 2908-5 | Transmission Boost Pressure Valve Actuator (eMRV): Current Below Normal (High Side J1-67) | Solenoid Valve - Test |
| 2908-6 | Transmission Boost Pressure Valve Actuator (eMRV): Current Above Normal (High Side J1-67) | Solenoid Valve - Test |
| 2908-11 | Transmission Boost Pressure Valve Actuator (eMRV): Other Failure Mode (Coil Resistance?) (High Side J1-67) | Solenoid Valve - Test |
| 3823-3 | Transmission Boost Pressure Valve Actuator: Current Above Normal | Solenoid Valve - Test |
| 3823-4 | Transmission Torque Converter Oil Outlet Temperature: Voltage Above Normal | Sensor Signal (Analog, Passive) - Test |
| 3825-2 | Transmission Torque Converter Oil Outlet Temperature: Voltage Below Normal | Sensor Signal (Analog, Passive) - Test |
| 3825-2 | Transmission Output Speed 2: Erratic, Intermittent, or Incorrect | Speed Sensor - Test |
| 3825-2 | Transmission Output Speed 2: Voltage Below Normal | Speed Sensor - Test |
| 3825-8 | Transmission Output Speed 2: Abnormal Frequency, Pulse Width, or Period | Speed Sensor - Test |
| 4051-3 | PTO #1 Voltage Above Normal | Electrical Power Supply - Test |
| 4051-5 | PTO #1 Current Below Normal | Electrical Power Supply - Test |
| 4051-6 | PTO #1 Current Above Normal | Electrical Power Supply - Test |
| 4053-3 | PTO #2 Voltage Above Normal | Electrical Power Supply - Test |
| 4053-5 | PTO #2 Current Below Normal | Electrical Power Supply - Test |
| 4053-6 | PTO #2 Current Above Normal | Electrical Power Supply - Test |
| 4217-6 | Transmission Shift Modulation Solenoid Valve (eMRV): Current Above Normal (Low Side/Driver Return) | Solenoid Valve - Test |
| 6911-2 | Transmission Internal Component #1 Speed: Erratic, Intermittent, or Incorrect | Speed Sensor - Test |
| 6911-4 | Transmission Internal Component #1 Speed: Voltage Below Normal | Speed Sensor - Test |
| 6911-8 | Transmission Internal Component #1 Speed: Abnormal Frequency, Pulse Width, or Period | Speed Sensor - Test |
| 6912-2 | Transmission Internal Component #2 Speed: Erratic, Intermittent, or Incorrect | Speed Sensor - Test |
| 6912-4 | Transmission Internal Component #2 Speed: Voltage Below Normal | Speed Sensor - Test |
| 6912-8 | Transmission Internal Component #2 Speed: Abnormal Frequency, Pulse Width, or Period | Speed Sensor - Test |
Caterpillar Information System:
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CX38-P892 Well Servicing Transmission Transmission Does Not Automatically Shift Back Into Gear
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