Bad transmission solenoid symptoms include delayed or erratic shifting, the transmission skipping gears or getting stuck in one gear, harsh shifts, and a check engine light with a solenoid code such as P0750. Solenoids are electrically operated valves that the transmission computer uses to direct fluid and select gears, so a weak or failed solenoid, its wiring or dirty fluid can all upset shifting.
What transmission solenoids do
- Shift solenoids open and close fluid passages in the valve body to apply the clutches for each gear.
- Pressure control solenoids set line pressure, which affects how firm each shift feels.
- The torque converter clutch (TCC) solenoid controls lockup of the torque converter at cruise.
Common symptoms
- Delayed or erratic shifts: gears change late, early or unpredictably.
- Stuck in gear or limp mode: the computer holds a single gear to protect the transmission.
- Skipping gears or refusing to downshift.
- Harsh or slipping shifts from incorrect line pressure.
- Lockup problems: shudder at cruise, or stalling when stopping if the converter will not unlock.
- Check engine light with transmission codes.
Solenoid codes
| Code | Meaning |
|---|---|
| P0750, P0755, P0760, P0765, P0770 | Shift solenoid A, B, C, D or E malfunction |
| P0740 | Torque converter clutch circuit |
Exact definitions vary by manufacturer, so look up the code for your vehicle. A code points to the circuit, which includes wiring and connectors, not always the solenoid itself.
What causes solenoid problems
- Low or contaminated fluid: debris and varnish make solenoids stick. Check the level and transmission fluid color first.
- Wiring and connectors: corrosion, chafed wires or a loose connector, often where the harness enters the case.
- Worn solenoids: coils fail electrically or valves wear.
- Control module faults: a failing transmission control module can mimic solenoid trouble. On some modern transmissions the solenoids and control module are built together inside the case.
Diagnosis and repair
- Scan for codes and note any that repeat.
- Check fluid level and condition, and service the fluid if it is due.
- Inspect the harness and connectors, and test solenoid resistance against the specification.
- Replace the faulty solenoid or solenoid pack; on many transmissions they are reached by removing the pan.
If shifting problems come with slipping, burnt fluid or metal in the pan, the transmission may have internal damage; see transmission slipping: signs and causes. When a replacement makes more sense, find your unit by code on our transmissions page; what transmission do I have? helps you identify it.
More guides: 4L60E shift solenoid chart · 68RFE solenoid pack · transmission solenoid pack · car jerks when shifting · valve body problems · transmission line pressure · bad TCM symptoms · bad transmission speed sensor symptoms.
Trouble codes: P0750 Shift Solenoid A · P0740 Torque Converter Clutch Circuit · P0700 Transmission Control System · P0753 Shift Solenoid A Electrical · P0776 Pressure Control Solenoid B · P0796 Pressure Control Solenoid C · P0751 Shift Solenoid A Stuck Off · P0756 Shift Solenoid B Stuck Off · P0758 Shift Solenoid B Electrical · P0743 TCC Circuit Electrical · P0755 Shift Solenoid B · P0757 Shift Solenoid B Stuck On · P0760 Shift Solenoid C · P0763 Shift Solenoid C Electrical · P0765 Shift Solenoid D · P0768 Shift Solenoid D Electrical · P0770 Shift Solenoid E · P0773 Shift Solenoid E Electrical · P0745 Pressure Control Solenoid A · P0746 Pressure Control Solenoid A Performance · P0747 Pressure Control Solenoid A Stuck On · P0777 Pressure Control Solenoid B Stuck On · P0778 Pressure Control Solenoid B Electrical · P0797 Pressure Control Solenoid C Stuck On · all OBD2 codes.
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