Every OBD-II code in the P07xx-P09xx range is transmission-related. This is the complete reference — what each code means, common cause, and the fix. Bookmark this page; you will use it weekly.
Generic "transmission has a fault" code. Always paired with another P07xx code that tells you the specific issue. ACTION: scan for additional codes.
TCM detected something out of expected operating range. Could be sensor signal, solenoid resistance, or fluid pressure. ACTION: live data scan, check TCM mechanical and electrical inputs.
TCM internal electrical fault. May indicate TCM failure or wiring issue. ACTION: scan TCM voltage, check ground straps.
TFT sensor showing erratic or out-of-range temperature. ACTION: replace TFT sensor if resistance check fails.
TFT sensor reading too low (open circuit). ACTION: replace sensor or check wiring continuity.
TFT sensor reading too high (short to ground). ACTION: replace sensor.
Input shaft RPM signal missing or out of range. ACTION: replace input speed sensor.
Input sensor reading erratic. Often paired with low fluid or solenoid wear. ACTION: verify fluid, then sensor.
No signal from input speed sensor. Replace sensor.
Output shaft RPM signal missing. ACTION: replace output speed sensor.
Same as P0720 — sensor or wiring failure.
TCM calculated wrong ratio for 6th gear. Internal clutch slippage or sensor fault.
Generic ratio fault. Cross-reference with other codes.
Slippage in first gear. Could be clutch wear or sensor issue.
Slippage in second gear. Common on 4L60E and 4R75W.
Slippage in third gear.
Slippage in fourth gear. Common 4L80E direct drum failure.
Slippage in fifth gear on 5-speed or 6-speed.
Reverse gear slippage or 3-5 reverse drum failure (6L80).
Torque converter clutch circuit fault. ACTION: replace TCC solenoid first.
Torque converter clutch failing to engage. Most common cause: TCC solenoid stuck. Second most common: converter clutch glazed.
Torque converter clutch stuck engaged. Engine stalls at idle when in gear. ACTION: replace TCC solenoid.
Wiring fault to TCC solenoid. Check harness continuity.
TCC engaging and disengaging unpredictably. Solenoid wear or fluid pressure issue.
EPC solenoid not responding to PCM commands. ACTION: replace EPC.
Line pressure too low. EPC failure or pump wear.
Line pressure stuck at maximum. Replace EPC.
EPC wiring fault. Check harness.
Shift solenoid A failure. Common 4L60E / 4L80E / 6L80 code.
Solenoid A not engaging. Usually means no 1-2 shift or no 3-4 shift.
Solenoid A always energized. Wrong gear engagements.
Wiring or solenoid coil fault.
Intermittent solenoid signal.
Shift solenoid B failure. Often paired with P0750.
No 2-3 shift or no overdrive.
Stuck shift schedule.
Wiring or coil fault.
E solenoid wiring fault on 5-speed or 6-speed transmissions.
Second pressure control solenoid on 6-speed. Common 6L80 / 6R80 code.
Second pressure control solenoid out of range. 6L80 1-2-3-4 shift solenoid is the common cause.
Third PCS on 6-speed or 8-speed. 6L80, 8L90 line-pressure fault.
Pressure sensor out of range. Sensor failure or wiring.
Pressure sensor reading too low.
Calculated fluid pressure out of expected range. 68RFE common code.
Line pressure dropping below threshold. Pump or pressure regulator wear.
PCM detected internal slippage. Generally precedes a rebuild.
EPC control circuit voltage low. Wiring or PCM driver fault.
EPC control circuit voltage high.
Solenoid A control voltage low. Wiring fault.
Solenoid A control voltage high.
Solenoid B control voltage low.
Solenoid B out of expected operating range.
Third solenoid (6-speed+) control circuit low.
Manual valve position sensor fault. 4L60E / 4L80E specific.
TCC slipping more than allowed threshold. Converter or fluid pressure issue. Common 4L60E code.
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