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Drivetrain & Transmission fault codes

Codes off the automated manual or automatic: clutch position and actuator faults, shift solenoids, range and splitter problems, driveline and output-shaft speed mismatch, retarder faults, and transmission oil temperature. A truck that won't take a gear on a grade is telling you about it here.

All 61 drivetrain & transmission SPN/FMI and OBD codes in the knowledge base are listed below — each with what it means, how serious it is, the most-likely causes, and what to check first.

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Drivetrain & Transmission codes (61)

SPN 160 · FMI 2Serious

Main shaft speed erratic

SPN 161 · FMI 2Serious

Input shaft speed erratic

SPN 162 · FMI 2Serious

Transmission output retarder speed erratic

SPN 177 · FMI 0Serious

Trans oil temperature very high

SPN 177 · FMI 3Serious

Trans oil temperature voltage high

SPN 177 · FMI 4Serious

Trans oil temperature voltage low

SPN 190 · FMI 9Serious

Engine speed signal abnormal update rate

SPN 191 · FMI 2Serious

Transmission output shaft speed erratic

SPN 191 · FMI 8Serious

Output shaft speed abnormal

SPN 191 · FMI 9Serious

Output shaft speed not updating (J1939)

SPN 560 · FMI 14Informational

Transmission requests clutch open

SPN 749 · FMI 7Serious

Gear selection failure

SPN 751 · FMI 7Serious

Countershaft brake — not responding

SPN 753 · FMI 2Serious

Range shift signal erratic

SPN 787 · FMI 7Serious

Shift finger not moving to commanded position

SPN 788 · FMI 5Serious

Clutch actuator open circuit

SPN 788 · FMI 6Serious

Clutch actuator short to ground

SPN 788 · FMI 7Serious

Clutch actuator not responding mechanically

SPN 793 · FMI 11Serious

Shift lever — root cause unknown

SPN 795 · FMI 7Serious

Inertia brake not responding

SPN 896 · FMI 7Serious

Transmission range valve not responding

SPN 898 · FMI 2Serious

Gear selector lever erratic

SPN 923 · FMI 2Serious

Reverse switch erratic

SPN 924 · FMI 2Serious

Drive position switch erratic

SPN 1762 · FMI 3Serious

Trans oil pressure voltage high

SPN 1762 · FMI 4Serious

Trans oil pressure voltage low

SPN 2919 · FMI 2Serious

Transmission output retarder position erratic

SPN 2920 · FMI 7Serious

Retarder not responding

P0700Serious

Transmission Control System Malfunction

P0706Serious

Transmission Range Sensor Circuit Range

P0711Serious

Transmission fluid temp sensor erratic

P0712Serious

Trans fluid temp — voltage low

P0713Serious

Trans fluid temp — voltage high

P0715Serious

Input/turbine speed sensor circuit erratic

P0716Serious

Input/turbine speed sensor — range/performance

P0717Serious

Input/turbine speed sensor — no signal

P0720Serious

Output speed sensor circuit erratic

P0721Serious

Output speed sensor — range/performance

P0722Serious

Output speed sensor — no signal

P0730Serious

Incorrect gear ratio

P0731Serious

1st gear ratio incorrect

P0732Serious

2nd gear ratio incorrect

P0733Serious

3rd gear ratio incorrect

P0734Serious

4th gear ratio incorrect

P0735Serious

5th gear ratio incorrect

P0736Serious

Reverse gear ratio incorrect

P0740Serious

Torque converter clutch solenoid circuit

P0741Serious

TCC stuck off

P0742Serious

TCC stuck on

P0748Serious

Pressure control solenoid A circuit

P0750Serious

Shift Solenoid A Malfunction

P0751Serious

Shift solenoid A performance

P0755Serious

Shift Solenoid B Malfunction

P0760Serious

Shift Solenoid C Malfunction

P0846Serious

Trans fluid pressure sensor B circuit

P0847Serious

Trans pressure sensor B — voltage low

P0848Serious

Trans pressure sensor B — voltage high

P0960Serious

Line pressure control solenoid circuit

P0962Serious

Pressure control solenoid A — voltage low

P0963Serious

Pressure control solenoid A — voltage high

P2761Serious

TCC pressure control solenoid circuit

Other systems

Aftertreatment & Emissions

100 codes

Engine

58 codes

Brakes, ABS & Stability

41 codes

Fuel System

39 codes

Electrical, Charging & Network

30 codes

Cooling, lubrication, HVAC and chassis/cab codes are listed on the fault code lookup, along with the search box that covers every code.

General diagnostic guidance for heavy-duty diesel equipment (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.